KEGG ID: 04520
KEGG Diagram for Adherens junction
There are 70 IPI Records from this pathway found in Rattus norvegicus.
Location of Adherens junction proteins on Rat Genome
| IPI Record | Position |
|---|---|
| 1: Acp1 | 6:48782802-48798831 |
| 2: Actb | 12:12047070-12050051 |
| 3: Actg1 | 10:109773489-109777655 |
| 4: Actn1 | 6:103110009-103282917 |
| 5: Actn2_predicted | 17:68670924-68773261 |
| 6: Actn3 | 1:207475569-207492267 |
| 7: Actn4 | 1:84000723-84073767 |
| 8: Acvr1b | 7:139937993-139958724 |
| 9: Acvr1c | 3:40027228-40102299 |
| 10: Af6 | 1:48827689-48911351 |
| 11: Baiap2 | 10:109351262-109418859 |
| 12: Catna1 | 18:27629915-27769375 |
| 13: Cdc42 | 5:156106131-156143040 |
| 14: Cdh1 | 19:36442693-36512091 |
| 15: Crebbp | 10:11598680-11724122 |
| 16: Csnk2a1 | 3:142588572-142609301 |
| 17: Csnk2a2_predicted | 19:10015349-10049896 |
| 18: Csnk2b | 20:3764565-3768982 |
| 19: Ctnna2_predicted | 4:110776309-111694975 |
| 20: Ctnnb1 | 8:125978161-125987670 |
| 21: Ctnnd1_predicted | 3:67809064-67860234 |
| 22: Egfr | 14:97617358-97788213 |
| 23: Erbb2 | 10:87219085-87242919 |
| 24: Farp2_predicted | 9:92807930-92907102 |
| 25: Fgfr1 | 16:70869944-70924029 |
| 26: Fyn | 20:43501853-43695567 |
| 27: Igf1r | 1:122704987-122989472 |
| 28: Insr | 12:2957511-3086795 |
| 29: IPI00765011 | :- |
| 30: IPI00766566 | :- |
| 31: Iqgap1_predicted | 1:136553443-136644285 |
| 32: Lef1 | 2:228550263-228689323 |
| 33: LMO7 | 15:85792940-85928469 |
| 34: Map3k7_predicted | 5:48252637-48308832 |
| 35: Mapk1 | 11:85968732-86030389 |
| 36: Mapk3 | 1:185935044-185941249 |
| 37: Met | 4:43134183-43211357 |
| 38: Pard3 | 19:57016001-57601905 |
| 39: Ptpn1 | 3:159070431-159119162 |
| 40: Ptpn6 | 4:160843701-160856821 |
| 41: Ptprb_predicted | 7:55615163-55711352 |
| 42: Ptprj | 3:74796435-74935394 |
| 43: Ptprm | 9:105785707-106503104 |
| 44: Pvrl1 | 8:46739494-46798633 |
| 45: Pvrl2 | 1:79021827-79059686 |
| 46: Pvrl3_predicted | 11:55843791-55940545 |
| 47: Rac1 | 12:11380314-11400531 |
| 48: Rac2 | 7:116520066-116532482 |
| 49: RGD1559455_predicted | 20:24686070-25040014 |
| 50: RGD1559826_predicted | 13:87276201-87293415 |
| 51: RGD1561602_predicted | 10:64681467-64804864 |
| 52: RGD1562230_predicted | 20:25900952-26268772 |
| 53: Rhoa | :- |
| 54: Smad2 | 18:73180290-73241713 |
| 55: Smad3 | 8:67803909-67952056 |
| 56: Smad4 | 18:70432832-70461485 |
| 57: Snai1 | 3:158676980-158681471 |
| 58: Snai2 | :- |
| 59: Src | 3:148157256-148170524 |
| 60: Ssx2ip | 2:244604360-244638522 |
| 61: Tcf3_predicted | 4:106128505-106149235 |
| 62: Tcf7_predicted | 10:37687192-37716600 |
| 63: Tgfbr1 | 5:63976868-64034058 |
| 64: Tgfbr2 | 8:120593595-120680453 |
| 65: Tjp1_predicted | 1:119686175-119750533 |
| 66: Vcl_predicted | 15:3480195-3654131 |
| 67: Wasf1 | :- |
| 68: Wasf2 | 5:151930684-151948306 |
| 69: Was_predicted | X:26434165-26444819 |
| 70: Yes1 | 9:112516842-112563988 |
There are 70 IPI Records from this pathway found in Mus musculus.
Location of Adherens junction proteins on Mouse Genome
| IPI Record | Position |
|---|---|
| 1: Acp1 | 12:31479708-31497634 |
| 2: Actb | 5:143168256-143171864 |
| 3: Actg1 | 11:120161781-120164582 |
| 4: Actn1 | 12:81086385-81179156 |
| 5: Actn2 | 13:12323759-12395065 |
| 6: Actn3 | 19:4861223-4877884 |
| 7: Actn4 | 7:28602011-28671040 |
| 8: Acvr1b | 15:101002159-101040635 |
| 9: Acvr1c | 2:58087208-58140193 |
| 10: Baiap2 | 11:119758853-119822869 |
| 11: Cdc42 | 4:136591778-136629755 |
| 12: Cdh1 | 8:109492497-109559375 |
| 13: Crebbp | 16:3999276-4128632 |
| 14: Csnk2a1 | 2:151918326-151973281 |
| 15: Csnk2a2 | 8:98337108-98377956 |
| 16: Csnk2b | 17:34724251-34729503 |
| 17: Ctnna1 | 18:35244863-35380747 |
| 18: Ctnna2 | 6:76812059-77775094 |
| 19: Ctnna3 | 10:62899394-64398190 |
| 20: Ctnnb1 | 9:120782173-120809205 |
| 21: Ctnnd1 | 2:84401622-84451514 |
| 22: Egfr | 11:16652206-16813912 |
| 23: Erbb2 | 11:98228574-98253806 |
| 24: Farp2 | 1:95358974-95452378 |
| 25: Fert2 | 17:63581484-63824640 |
| 26: Fgfr1 | 8:26997826-27039466 |
| 27: Fyn | 10:39059219-39254797 |
| 28: Igf1r | 7:67826372-68100293 |
| 29: Insr | 8:3155401-3279128 |
| 30: Iqgap1 | 7:80586294-80676807 |
| 31: Lef1 | 3:131099626-131213476 |
| 32: Lmo7 | 14:100725118-100821293 |
| 33: Map3k7 | 4:32292729-32349408 |
| 34: Mapk1 | 16:16896945-16961016 |
| 35: Mapk3 | 7:126550780-126556964 |
| 36: Met | 6:17441241-17521823 |
| 37: Nlk | 11:78383361-78513568 |
| 38: Pard3 | 8:129950335-130496920 |
| 39: Ptpn1 | 2:167623614-167668115 |
| 40: Ptpn6 | 6:124686727-124698484 |
| 41: Ptprb | 10:115679633-115785122 |
| 42: Ptprf | 4:117707733-117775378 |
| 43: Ptprj | 2:90233731-90381407 |
| 44: Ptprm | 17:66571893-67259402 |
| 45: Pvrl1 | 9:43495571-43558456 |
| 46: Pvrl2 | 7:18875186-18908047 |
| 47: Pvrl3 | 16:46314342-46416301 |
| 48: Pvrl4 | 1:173207030-173225256 |
| 49: Rac1 | 5:143761100-143783654 |
| 50: Rac2 | 15:78386424-78400038 |
| 51: Rac3 | 11:120537558-120540059 |
| 52: Rhoa | 9:108164298-108196026 |
| 53: Smad2 | 18:76367274-76431096 |
| 54: Smad3 | 9:63444773-63556000 |
| 55: Smad4 | :- |
| 56: Snai1 | 2:167229432-167234019 |
| 57: Snai2 | 16:14619437-14622963 |
| 58: Sorbs1 | 19:40348360-40451928 |
| 59: Src | 2:157115730-157163279 |
| 60: Ssx2ip | 3:146342041-146377521 |
| 61: Tcf3 | 6:72555889-72718465 |
| 62: Tcf7 | 11:52096027-52126602 |
| 63: Tcf7l2 | 19:55795070-55986503 |
| 64: Tgfbr1 | 4:47374405-47436024 |
| 65: Tgfbr2 | 9:115932995-116023987 |
| 66: Tjp1 | 7:65175115-65250189 |
| 67: Vcl | 14:19717950-19822228 |
| 68: Was | X:7238425-7247411 |
| 69: Wasf1 | 10:40571988-40626982 |
| 70: Wasf2 | 4:132402654-132471805 |
| 71: Wasf3 | 5:146689240-146774650 |
| 72: Wasl | 6:24563813-24614998 |
| 73: Yes1 | 5:32887814-32963638 |
There are 70 IPI Records from this pathway found in Homo sapiens.
Location of Adherens junction proteins on Human Genome
| IPI Record | Position |
|---|---|
| 1: ACP1 | 2:254869-268283 |
| 2: ACTB | 7:5533313-5535814 |
| 3: ACTN1 | 14:68410793-68515747 |
| 4: ACTN2 | 1:234916431-234994554 |
| 5: ACTN3 | 11:66070967-66087373 |
| 6: ACTN4 | 19:43830167-43913010 |
| 7: ACVR1B | 12:50494095-50677124 |
| 8: ACVR1C | 2:158097152-158193645 |
| 9: BAIAP2 | 17:76623557-76705827 |
| 10: CDC42 | 1:22235157-22292024 |
| 11: CDH1 | 16:67328696-67426943 |
| 12: CREBBP | 16:3716572-3870723 |
| 13: CSNK2A1 | 20:411340-472482 |
| 14: CSNK2A2 | 16:56749320-56789283 |
| 15: CTNNA1 | 5:138117006-138298619 |
| 16: CTNNA2 | 2:79732191-80729415 |
| 17: CTNNA3 | 10:67349725-69125933 |
| 18: CTNNB1 | 3:41216004-41256938 |
| 19: CTNND1 | 11:57236618-57343226 |
| 20: EGFR | 7:55054219-55242524 |
| 21: EP300 | 22:39817736-39905472 |
| 22: ERBB2 | 17:35104766-35138441 |
| 23: FARP2 | 2:241944384-242082928 |
| 24: FER | 5:108111422-108560441 |
| 25: FGFR1 | 8:38389406-38445296 |
| 26: FYN | 6:112088228-112301348 |
| 27: IGF1R | 15:97010302-97319034 |
| 28: INSR | 19:7067049-7245045 |
| 29: IQGAP1 | 15:88732477-88846479 |
| 30: LEF1 | 4:109188150-109309027 |
| 31: LMO7 | 13:75092571-75343063 |
| 32: MAP3K7 | 6:91280013-91353485 |
| 33: MAPK1 | 22:20446873-20551730 |
| 34: MAPK3 | 16:30032951-30042116 |
| 35: MET | 7:116099695-116223632 |
| 36: MLLT4 | 6:167970520-168115552 |
| 37: NLK | 17:23393309-23547529 |
| 38: PARD3 | 10:34438495-35144255 |
| 39: PTPN1 | 20:48560294-48634706 |
| 40: PTPN6 | 12:6930763-6940740 |
| 41: PTPRB | 12:69201231-69317469 |
| 42: PTPRF | 1:43769134-43861924 |
| 43: PTPRJ | 11:47958689-48146246 |
| 44: PTPRM | 18:7557817-8396160 |
| 45: PVRL1 | 11:119014018-119104645 |
| 46: PVRL2 | 19:50041390-50083476 |
| 47: PVRL3 | 3:112273555-112395063 |
| 48: PVRL4 | 1:159307409-159326013 |
| 49: RAC1 | 7:6380651-6410120 |
| 50: RAC2 | 22:35951238-35970241 |
| 51: RAC3 | 17:77582821-77585366 |
| 52: RHOA | 3:49371585-49424530 |
| 53: SMAD2 | 18:43618435-43711221 |
| 54: SMAD3 | 15:65145249-65274586 |
| 55: SMAD4 | 18:46810611-46860142 |
| 56: SNAI1 | 20:48032934-48038825 |
| 57: SNAI2 | 8:49992802-49996541 |
| 58: SORBS1 | 10:97061520-97311161 |
| 59: SRC | 20:35406502-35467239 |
| 60: SSX2IP | 1:84881978-84928816 |
| 61: TCF7 | 5:133478301-133511826 |
| 62: TCF7L1 | 2:85214245-85391012 |
| 63: TCF7L2 | 10:114700201-114917427 |
| 64: TGFBR1 | 9:100907233-100956406 |
| 65: TGFBR2 | 3:30622998-30710635 |
| 66: TJP1 | 15:27779656-27902010 |
| 67: VCL | 10:75427878-75549924 |
| 68: WAS | X:48427112-48434762 |
| 69: WASF1 | 6:110528382-110607819 |
| 70: WASF2 | 1:27603317-27689256 |
| 71: WASF3 | 13:26029840-26161085 |
| 72: WASL | 7:123109237-123176352 |
| 73: YES1 | 18:711747-802547 |
J Cell Physiol. 2009 Nov 19;
Sperry RB, Bishop NH, Bramwell JJ, Brodeur MN, Carter MJ, Fowler BT, Lewis ZB, Maxfield SD, Staley DM, Vellinga RM, Hansen MD
Development is punctuated by morphogenetic rearrangements of epithelial tissues, including detachment of motile cells during epithelial-mesenchymal transition (EMT). Dramatic actin rearrangements occur as cell-cell junctions are dismantled and cells become independently motile during EMT. Characterizing dynamic actin rearrangements and identifying actin machinery driving these rearrangements is essential for understanding basic mechanisms of cell-cell junction remodeling. Using immunofluorescence and live cell imaging of scattering MDCK cells we examine dynamic actin rearrangement events during EMT and demonstrate that zyxin-VASP complexes mediate linkage of dynamic medial actin networks to Adherens junction (AJ) membranes. A functional analysis of zyxin in EMT reveals its role in regulating disruption of actin membrane linkages at cell-cell junctions, altering cells' ability to fully detach and migrate independently during EMT. Expression of a constitutively active zyxin mutant results in persistent actin-membrane linkages and cell migration without loss of cell-cell adhesion. We propose zyxin functions in morphogenetic rearrangements, maintaining collective migration by transducing individual cells' movements through AJs, thus preventing the dissociation of individual migratory cells. J. Cell. Physiol. (c) 2009 Wiley-Liss, Inc.
PLoS One. 2009; 4(11): e7833
Finlayson AE, Freeman KW
Invasion through the extracellular matrix (ECM) is important for wound healing, immunological responses and metastasis. We established an invasion-based cell motility screen using Boyden chambers overlaid with Matrigel to select for pro-invasive genes. By this method we identified antisense to MARCKS related protein (MRP), whose family member MARCKS is a target of miR-21, a microRNA involved in tumor growth, invasion and metastasis in multiple human cancers. We confirmed that targeted knockdown of MRP, in both EpRas mammary epithelial cells and PC3 prostate cancer cells, promoted in vitro cell migration that was blocked by trifluoperazine. Additionally, we observed increased immunofluoresence of E-cadherin, beta-catenin and APC at sites of cell-cell contact in EpRas cells with MRP knockdown suggesting formation of Adherens junctions. By wound healing assay we observed that reduced MRP supported collective cell migration, a type of cell movement where Adherens junctions are maintained. However, destabilized Adherens junctions, like those seen in EpRas cells, are frequently important for oncogenic signaling. Consequently, knockdown of MRP in EpRas caused loss of tumorigenesis in vivo, and reduced Wnt3a induced TCF reporter signaling in vitro. Together our data suggest that reducing MRP expression promotes formation of Adherens junctions in EpRas cells, allowing collective cell migration, but interferes with oncogenic beta-catenin signaling and tumorigenesis.
J Biochem. 2009 Nov 16;
Ozaki C, Obata S, Yamanaka H, Tominaga S, Suzuki ST
The accumulation of classical cadherins is essential for their function, but the mechanism is poorly understood. Hence, we investigated the accumulation of E- and N-cadherin and the formation of cell junctions in epithelial cells. Immunostaining revealed a scattered dot-like accumulation of E- and N-cadherin throughout the lateral membrane in MDCK II and other epithelial cells. Mutant E-cadherin lacking the ss-catenin binding site accumulated granularly at cell-cell contact sites and showed weak cell aggregation activity in cadherin-deficient epithelial cells, MIA PaCa2 cells. Mutant E-cadherin lacking the p120-catenin binding site exhibited scattered punctate accumulation and strong cell adhesion activity in MIA PaCa2 cells. Electron microscopy demonstrated that MIA PaCa2 transfectants of E-cadherin containing ss-catenin binding site formed Adherens junction, whereas E-cadherin lacking the binding site did not. Mutant N-cadherins showed accumulation properties similar to those of corresponding mutant E-cadherins. Moreover, wild type and mutant N-cadherin lacking the p120-catenin binding site showed subapical accumulation in polarized DLD-1 cells, whereas mutant N-cadherin lacking ss-catenin binding site did not. These results indicate that the extracellular domains of E- and N-cadherin determines the basic localization pattern, whereas the cytoplasmic domains modulate it thereby affects the cell adhesion activity, subapical accumulation, and the formation of Adherens junction.
J Exp Med. 2009 Nov 16;
Knezevic N, Tauseef M, Thennes T, Mehta D
The inflammatory mediator thrombin proteolytically activates protease-activated receptor (PAR1) eliciting a transient, but reversible increase in vascular permeability. PAR1-induced dissociation of Galpha subunit from heterotrimeric Gq and G12/G13 proteins is known to signal the increase in endothelial permeability. However, the role of released Gbetagamma is unknown. We now show that impairment of Gbetagamma function does not affect the permeability increase induced by PAR1, but prevents reannealing of Adherens junctions (AJ), thereby persistently elevating endothelial permeability. We observed that in the naive endothelium Gbeta1, the predominant Gbeta isoform is sequestered by receptor for activated C kinase 1 (RACK1). Thrombin induced dissociation of Gbeta1 from RACK1, resulting in Gbeta1 interaction with Fyn and focal adhesion kinase (FAK) required for FAK activation. RACK1 depletion triggered Gbeta1 activation of FAK and endothelial barrier recovery, whereas Fyn knockdown interrupted with Gbeta1-induced barrier recovery indicating RACK1 negatively regulates Gbeta1-Fyn signaling. Activated FAK associated with AJ and stimulated AJ reassembly in a Fyn-dependent manner. Fyn deletion prevented FAK activation and augmented lung vascular permeability increase induced by PAR1 agonist. Rescuing FAK activation in fyn(-/-) mice attenuated the rise in lung vascular permeability. Our results demonstrate that Gbeta1-mediated Fyn activation integrates FAK with AJ, preventing persistent endothelial barrier leakiness.
Neuron. 2009 Nov 12; 64(3): 320-7
Matter C, Pribadi M, Liu X, Trachtenberg JT
Delta-catenin is a brain-specific member of the Adherens junction complex that localizes to the postsynaptic and dendritic compartments. This protein is likely critical for normal cognitive function; its hemizygous loss is linked to the severe mental retardation syndrome Cri-du-Chat and it directly interacts with presenilin-1 (PS1), the protein most frequently mutated in familial Alzheimer's disease. Here we examine dendritic structure and cortical function in vivo in mice lacking delta-catenin. We find that in cerebral cortex of 5-week-old mice, dendritic complexity, spine density, and cortical responsiveness are similar between mutant and littermate controls; thereafter, mutant mice experience progressive dendritic retraction, a reduction in spine density and stability, and concomitant reductions in cortical responsiveness. Our results indicate that delta-catenin regulates the maintenance of dendrites and dendritic spines in mature cortex but does not appear to be necessary for the initial establishment of these structures during development.
Genetic and protein changes of E-cadherin in meningiomas.
J Cancer Res Clin Oncol. 2009 Nov 12;
Pećina-Šlaus N, Nikuševa Martić T, Deak AJ, Zeljko M, Hrašćan R, Tomas D, Musani V
PURPOSE: The molecular mechanisms and candidate genes involved in development of meningiomas still needs investigation and elucidation. METHODS: In the present study 60 meningiomas were analyzed regarding changes of tumor suppressor gene E-cadherin (CDH1), a component of Adherens junction and an indirect modulator of the wnt signaling. Gene instability was tested by polymerase chain reaction/loss of heterozygosity (LOH) method. Protein expression was analyzed by immunohistochemistry. RESULTS: The results of our analysis showed altogether 32% of samples with LOH of the CDH1 gene. Interestingly, another type of genomic instability was detected; replication error-positive samples (RER+). Three out of 28 heterozygous samples were RER+ (11%). The instability is the result of impaired cellular mismatch repair. Fibrous and angiomatous cases showed higher percent of genetic changes, 67 and 75%, respectively. Immunostaining showed that overall 73% of samples had downregulation of E-cadherin expression. Intense downregulation of E-cadherin was noticed in tumors with grades II and III. Five out of nine samples with LOH were accompanied with the downregulation of E-cadherin protein expression (56%). One RER+ sample had lower expression of E-cadherin. We noticed that 36.4% of samples with lower E-cadherin expression had beta-catenin located in the nucleus. Also, 75% of samples with genomic instabilities had beta-catenin in the nucleus. Our findings demonstrated that there is significant association between the genetic changes of CDH1 and the nuclear localization of beta-catenin protein (chi(2) = 5.25, df = 1, P < 0.022). Beta-catenin was progressively upregulated from meningothelial to atypical, while 60% of anaplastic showed upregulation and nuclear localization of the protein. CONCLUSIONS: Our results suggest that genetic instabilities of the E-cadherin gene have a role in meningioma development and progression. Detected microsatellite instability indicates that mismatch repair may also be targeted in meningioma.
G Ital Dermatol Venereol. 2009 Dec; 144(6): 689-700
Jensen JM, Proksch E
The skin provides an effective barrier between the organism and the environment, preventing the invasion of pathogens and fending off chemical and physical assaults, as well as the unregulated loss of water and solutes. In this review we provide an overview of several components of the physical barrier, as well as how barrier function is regulated and altered in association with dermatoses. The physical barrier localized primarily in the stratum corneum (SC) and consists of protein-enriched cells (corneocytes with cornified envelope and cytoskeletal elements, as well as corneodesmosomes) and lipid-enriched intercellular domains. The nucleated epidermis, with its tight, gap and Adherens junctions, additional desmosomes and cytoskeletal elements, also contributes to the barrier. Lipids are synthesized in the keratinocytes during epidermal differentiation and are then extruded into the extracellular domains, where they form lipid-enriched extracellular layers. The cornified cell envelope, a robust protein/lipid polymer structure, is located below the cytoplasmic membrane on the exterior of the corneocytes. Ceramides A and B, forming the backbone for the subsequent addition of free ceramides, free fatty acids and cholesterol in the SC, are covalently bound to cornified envelope proteins. Filaggrin is cross-linked to the cornified envelope and aggregates keratin filaments into macrofibrils. Cytokines, cAMP and calcium influence the formation and maintenance of barrier function. Changes in lipid composition and epidermal differentiation lead to a disturbed skin barrier, which allows the entry of environmental allergens, immunological reaction and inflammation in atopic dermatitis. A disturbed skin barrier is an important component in the pathogenesis of contact dermatitis, ichthyosis, psoriasis, and atopic dermatitis.
De novo synthesis of {beta}-catenin via H-Ras and MEK regulates airway smooth muscle growth.
FASEB J. 2009 Nov 11;
Gosens R, Baarsma HA, Heijink IH, Oenema TA, Halayko AJ, Meurs H, Schmidt M
beta-Catenin is a component of Adherens junctions that also acts as a transcriptional coactivator when expressed in the nucleus. Growth factors are believed to regulate the nuclear expression of beta-catenin via inactivation of glycogen synthase kinase 3 (GSK-3) by phosphorylation, resulting in increased beta-catenin protein stability. Here, we report on a novel pathway that regulates the expression and nuclear presence of beta-catenin. In proliferating human airway smooth muscle cells, we observed increased expression of beta-catenin, which was required for proliferation. Interestingly, increased beta-catenin expression was accompanied by an increase in beta-catenin mRNA and was independent of beta-catenin liberation from the plasma membrane, suggesting a role for de novo synthesis. This was confirmed using actinomycin D and cycloheximide, which abrogated the induction and nuclear localization of beta-catenin protein. GSK-3 inhibition using SB216763 failed to regulate beta-catenin mRNA. However, expression of dominant negative H-Ras or pharmacological inhibition of MEK reduced serum and TGF-beta-induced beta-catenin mRNA and protein. Collectively, these data indicate that beta-catenin is an important signaling intermediate in airway smooth muscle growth and that its cellular accumulation and nuclear localization require de novo protein synthesis effected, in part, via H-Ras and MEK.-Gosens, R., Baarsma, H. A., Heijink, I. H., Oenema, T. A., Halayko, A. J., Meurs, H., Schmidt, M. De novo synthesis of beta-catenin via H-Ras and MEK regulates airway smooth muscle growth.
Cadherin-2 controls directional chain migration of cerebellar granule neurons.
PLoS Biol. 2009 Nov; 7(11): e1000240
Rieger S, Senghaas N, Walch A, Köster RW
Long distance migration of differentiating granule cells from the cerebellar upper rhombic lip has been reported in many vertebrates. However, the knowledge about the subcellular dynamics and molecular mechanisms regulating directional neuronal migration in vivo is just beginning to emerge. Here we show by time-lapse imaging in live zebrafish (Danio rerio) embryos that cerebellar granule cells migrate in chain-like structures in a homotypic glia-independent manner. Temporal rescue of zebrafish Cadherin-2 mutants reveals a direct role for this adhesion molecule in mediating chain formation and coherent migratory behavior of granule cells. In addition, Cadherin-2 maintains the orientation of cell polarization in direction of migration, whereas in Cadherin-2 mutant granule cells the site of leading edge formation and centrosome positioning is randomized. Thus, the lack of adhesion leads to impaired directional migration with a mispositioning of Cadherin-2 deficient granule cells as a consequence. Furthermore, these cells fail to differentiate properly into mature granule neurons. In vivo imaging of Cadherin-2 localization revealed the dynamics of this adhesion molecule during cell locomotion. Cadherin-2 concentrates transiently at the front of granule cells during the initiation of individual migratory steps by intramembraneous transport. The presence of Cadherin-2 in the leading edge corresponds to the observed centrosome orientation in direction of migration. Our results indicate that Cadherin-2 plays a key role during zebrafish granule cell migration by continuously coordinating cell-cell contacts and cell polarity through the remodeling of Adherens junctions. As Cadherin-containing Adherens junctions have been shown to be connected via microtubule fibers with the centrosome, our results offer an explanation for the mechanism of leading edge and centrosome positioning during nucleokinetic migration of many vertebrate neuronal populations.
J Proteome Res. 2009 Nov 9;
Woodcock SA, Jones RC, Edmondson RD, Malliri A
The Rac-specific GEF (guanine-nucleotide exchange factor) Tiam1 has important functions in multiple cellular processes including proliferation, apoptosis and Adherens junction maintenance. Here we describe a modified tandem affinity purification (TAP) technique that we have applied to specifically enrich Tiam1-containing protein complexes from mammalian cells. Using this technique in conjunction with LC-MS/MS mass spectrometry, we have identified additional Tiam1-interacting proteins not seen with the standard technique, and have identified multiple 14-3-3 family members as Tiam1 interactors. We confirm the Tiam1/14-3-3 protein interaction by GST-pulldown and coimmunoprecipitation experiments, show that it is phosphorylation-dependent, and that they colocalize in cells. The interaction is largely dependent on the N-terminal region of Tiam1; within this region, there are four putative phospho-serine-containing 14-3-3 binding motifs, and we confirm that two of them (Ser172 and Ser231) are phosphorylated in cells using mass spectrometry. Moreover, we show that phosphorylation at three of these motifs (containing Ser60, Ser172 and Ser231) is required for the binding of 14-3-3 proteins to this region of Tiam1. We show that phosphorylation of these sites does not affect Tiam1 activity; significantly however, we demonstrate that phosphorylation of the Ser60-containing motif is required for the degradation of Tiam1. Thus, we have established and proven methodology that allows the identification of additional protein-protein interactions in mammalian cells, resulting in the discovery of a novel mechanism of regulating Tiam1 stability.
The Structure of Tight junctions in Mouse Submandibular Gland.
Anat Rec (Hoboken). 2009 Nov 6;
Kikuchi K, Kawedia J, Menon AG, Hand AR
Salivary gland cells are joined by junctional complexes consisting of a tight junction (TJ), zonula Adherens and one or more desmosomes. TJs regulate paracellular permeability, maintain separate apical and basolateral membrane domains, and serve as signaling centers. We examined TJs of mouse submandibular glands (SMG) in thin sections and freeze-fracture replicas. TJs between acinar cells and between intercalated duct cells had 2-6 parallel strands on the protoplasmic fracture face, with occasional branches, interconnections and free ends, and corresponding grooves on the extracellular face. Granular duct cell TJs had 2-30 strands, a depth of =0.5 mum, and occasional loops extending further basally. Where 3 or 4 cells met, the TJs extended basally =1 mum and consisted of 2 parallel boundary strands into which the apical strands inserted. Quantitative analyses showed significant differences in TJ complexity, measured by fractal geometry, and strand number of acinar compared to granular duct cells, and a greater number of strands in male compared to female granular ducts. Pilocarpine stimulation increased TJ strand number in female acinar cells, and increased complexity of male granular duct cell TJs. As the salivary gland water channel aquaporin 5 (AQP5) has been proposed to functionally interact with TJs to regulate salivary fluid composition, we also studied glands from AQP5 knock-out mice. In males lacking AQP5, granular duct TJs were more complex than those of wild-type mice, and exhibited more strands following pilocarpine stimulation. The results demonstrate specific gender, cell type and genetic differences in TJ structure and response to stimulation. Anat Rec, 2009. (c) 2009 Wiley-Liss, Inc.
Sec3-containing Exocyst Complex Is Required for Desmosome Assembly in Mammalian Epithelial Cells.
Mol Biol Cell. 2009 Nov 4;
Andersen NJ, Yeaman C
Monitoring Editor: Patrick J. Brennwald The Exocyst is a conserved multi-subunit complex involved in the docking of post-Golgi transport vesicles to sites of membrane remodeling during cellular processes such as polarization, migration and division. In mammalian epithelial cells, Exocyst complexes are recruited to nascent sites of cell-cell contact in response to E-cadherin-mediated adhesive interactions, and this event is an important early step in the assembly of intercellular junctions. Sec3 has been hypothesized to function as a spatial landmark for the development of polarity in budding yeast, but its role in epithelial cells has not been investigated. Here we provide evidence in support of a function for a Sec3-containing Exocyst complex in the assembly or maintenance of desmosomes, adhesive junctions that link intermediate filament networks to sites of strong intercellular adhesion. We show that Sec3 associates with a subset of Exocyst complexes that are enriched at desmosomes. Moreover, we found that membrane recruitment of Sec3 is dependent on cadherin-mediated adhesion, but occurs later than that of the known Exocyst components Sec6 and Sec8 that are recruited to Adherens junctions. RNAi-mediated suppression of Sec3 expression led to specific impairment of both the morphology and function of desmosomes, without noticeable effect on Adherens junctions. These results suggest that two different exocyst complexes may function in basal-lateral membrane trafficking, and will enable us to better understand how exocytosis is spatially organized during development of epithelial plasma membrane domains.
J Cell Sci. 2009 Dec 1; 122(Pt 23): 4319-4329
Miyata M, Ogita H, Komura H, Nakata S, Okamoto R, Ozaki M, Majima T, Matsuzawa N, Kawano S, Minami A, Waseda M, Fujita N, Mizutani K, Rikitake Y, Takai Y
Afadin is an actin-filament-binding protein that binds to nectin, an immunoglobulin-like cell-cell adhesion molecule, and plays an important role in the formation of Adherens junctions. Here, we show that afadin, which did not bind to nectin and was localized at the leading edge of moving cells, has another role: enhancement of the directional, but not random, cell movement. When NIH3T3 cells were stimulated with platelet-derived growth factor (PDGF), afadin colocalized with PDGF receptor, alphavbeta3 integrin and nectin-like molecule-5 at the leading edge and facilitated the formation of leading-edge structures and directional cell movement in the direction of PDGF stimulation. However, these phenotypes were markedly perturbed by knockdown of afadin, and were dependent on the binding of afadin to active Rap1. Binding of Rap1 to afadin was necessary for the recruitment of afadin and the tyrosine phosphatase SHP-2 to the leading edge. SHP-2 was previously reported to tightly regulate the activation of PDGF receptor and its downstream signaling pathway for the formation of the leading edge. These results indicate that afadin has a novel role in PDGF-induced directional cell movement, presumably in cooperation with active Rap1 and SHP-2.
Am J Physiol Lung Cell Mol Physiol. 2009 Oct 30;
Zhao YD, Ohkawara H, Vogel SM, Malik AB, Zhao YY
Since thrombin activation of endothelial cells (ECs) is well known to increase endothelial permeability by disassembly of Adherens junctions (AJs) and actino-myosin contractility mechanism involving myosin light chain (MLC) phosphorylation, we investigated the effects of bone marrow-derived progenitor cells (BMPCs) on the thrombin-induced endothelial permeability response. We observed that addition of BMPCs to endothelial monolayers at a fixed ratio prevented the thrombin-induced decrease in transendothelial electrical resistance, a measure of AJ integrity, and increased mouse pulmonary microvessel filtration coefficient, a measure of transvascular liquid permeability. The barrier protection was coupled to increased VE-cadherin expression and increased Cdc42 activity in ECs. Using siRNA to deplete Cdc42 in ECs, we demonstrated a key role of Cdc42 in signaling the BMPC-induced endothelial barrier protection. Endothelial integrity induced by BMPCs was also secondary to inhibition of MLC phosphorylation in ECs. Thus, BMPCs interacting with ECs prevent thrombin-induced endothelial hyper-permeability by a mechanism involving AJ barrier annealing, inhibition of MLC phosphorylation, and activation of Cdc42. Key words: Adherens junctions, VE-cadherin, myosin light chain, Cdc42.
Endothelial IQGAP1 Regulates Efficient Lymphocyte Transendothelial Migration.
Eur J Immunol. 2009 Oct 28;
Nakhaei-Nejad M, Zhang QX, Murray AG
Leukocyte movement from the blood to the tissues is a fundamental process in acute and chronic inflammatory diseases. While the role of endothelial cells (EC) to recruit leukocytes to sites of inflammation is well known, the mechanisms that control remodeling of EC shape and adhesive contacts during leukocyte transendothelial migration (TEM) are not completely understood. We studied the role of IQGAP1, an adaptor protein that binds to F-actin and microtubules (MT) at interendothelial junctions, during lymphocyte TEM. EC IQGAP1 knockdown decreases MT tethered to the Adherens junction (AJ), and decreases lymphocyte TEM to approximately 70% (p<0.05) vs. control. Similarly, loss of AJ-associated MT induced by brief nocodazole (ND) treatment decreases lymphocyte TEM to approximately 65% of control (p<0.01). Confocal microscopy imaging indicates that EC IQGAP1 knockdown and MT depolymerization both result in lymphocyte accumulation above the VE-cadherin junctions and reduces the fraction of adherent lymphocytes that complete diapedesis across interendothelial cell junctions. However, we observe no change in VE-cadherin gap formation underlying adherent lymphocytes among control, IQGAP1 knockdown, or MT deploymerized EC monolayers. These data indicate that IQGAP1 contributes to MT stability at endothelial junctions. Further, IQGAP1 is involved in junction remodeling required for efficient lymphocyte diapedesis, independent of VE-cadherin gap formation.
Pediatr Surg Int. 2009 Oct 24;
Doi T, Puri P, Bannigan J, Thompson J
PURPOSE: Administration of cadmium (Cd) causes omphalocele in the chick embryo. The earliest histological changes in the chick Cd model are the breakdown of Adherens junctions (AJs). Calreticulin (CRT) plays a key role in Ca(2+) signaling and cell adhesion. Ca(2+) signaling in the Cd chick model is known to be altered. The calcium-dependent adhesion molecule, E-cadherin, and its associate, beta-catenin, are key components of AJs regulated by CRT. CRT knockouts display omphalocele. We hypothesized that CRT, E-cadherin and beta-catenin are downregulated during early embryogenesis in the Cd chick model. METHODS: After 60 h (H) incubation, chicks were harvested 1H, 4H, and 8H post treatment with saline or Cd and divided into controls and Cd. RT-PCR was performed to evaluate mRNA levels of CRT, E-cadherin and beta-catenin in the Cd chick model. RESULTS: The mRNA levels of CRT were significantly decreased in the Cd group at 1H compared to controls (p < 0.05). The mRNA levels of E-cadherin and beta-catenin were significantly decreased at 4H in the Cd group compared to controls (p < 0.05). There were no significant differences at 8H. CONCLUSION: Downregulation of CRT, E-cadherin and beta-catenin genes may cause omphalocele in the Cd chick model by disrupting CRT-mediated Ca(2+) signaling and AJs.
Rab11 helps maintain apical crumbs and Adherens junctions in the Drosophila embryonic ectoderm.
PLoS One. 2009; 4(10): e7634
Roeth JF, Sawyer JK, Wilner DA, Peifer M
BACKGROUND: Tissue morphogenesis and organogenesis require that cells retain stable cell-cell adhesion while changing shape and moving. One mechanism to accommodate this plasticity in cell adhesion involves regulated trafficking of junctional proteins. METHODOLOGY/PRINCIPAL FINDINGS: Here we explored trafficking of junctional proteins in two well-characterized model epithelia, the Drosophila embryonic ectoderm and amnioserosa. We find that DE-cadherin, the transmembrane protein of Adherens junctions, is actively trafficked through putative vesicles, and appears to travel through both Rab5-positive and Rab11-positive structures. We manipulated the functions of Rab11 and Rab5 to examine the effects on junctional stability and morphogenesis. Reducing Rab11 function, either using a dominant negative construct or loss of function alleles, disrupts integrity of the ectoderm and leads to loss of Adherens junctions. Strikingly, the apical junctional regulator Crumbs is lost before AJs are destabilized, while the basolateral protein Dlg remains cortical. Altering Rab5 function had less dramatic effects, not disrupting Adherens junction integrity but affecting dorsal closure. CONCLUSIONS/SIGNIFICANCE: We contrast our results with what others saw when disrupting other trafficking regulators, and when disrupting Rab function in other tissues; together these data suggest distinct mechanisms regulate junctional stability and plasticity in different tissues.
Cross-talk between tight and anchoring junctions-lesson from the testis.
Adv Exp Med Biol. 2008; 636: 234-54
Yan HH, Mruk DD, Lee WM, Cheng CY
Spermatogenesis takes place in the seminiferous tubules in adult testes such as rats, in which developing germ cells must traverse the seminiferous epithelium while spermatogonia (2n, diploid) undergo mitotic and meiotic divisions, and differentiate into elongated spermatids (1n, haploid). It is conceivable that this event involves extensive junction restructuring particularly at the blood-testis barrier (BTB, a structure that segregates the seminiferous epithelium into the basal and the adluminal compartments) that occurs at stages VII-VIII of the seminiferous epithelial cycle. As such, cross-talk between tight (TJ) and anchoring junctions [e.g., basal ectoplasmic specialization (basal ES), Adherens junction (AJ), desmosome-like junction (DJ)] at the BTB must occur to coordinate the transient opening of the BTB to facilitate preleptotene spermatocyte migration. Interestingly, while there are extensively restructuring at the BTB during the epithelial cycle, the immunological barrier function of the BTB must be maintained without disruption even transiently. Recent studies using the androgen suppression and Adjudin models have shown that anchoring junction restructuring that leads to germ cell loss from the seminiferous epithelium also promotes the production of AJ (e.g., basal ES) proteins (such as N-cadherins, catenins) at the BTB site. We postulate the testis is using a similar mechanism during spermatogenesis at stage VIII of the epithelial cycle that these induced basal ES proteins, likely form a "patch" surrounding the BTB, transiently maintain the BTB integrity while TJ is "opened", such as induced by TGF-b3 or TNFa, to facilitate preleptotene spermatocyte migration. However, in other stages of the epithelial cycle other than VII and VIII when the BTB remains "closed" (for approximately 10 days), anchoring junctions (e.g., AJ, DJ, and apical ES) restructuring continues to facilitate germ cell movement. Interestingly, the mechanism(s) that governs this communication between TJ and anchoring junction (e.g., basal ES and AJ) in the testis has remained obscure until recently. Herein, we provide a critical review based on the recently available data regarding the cross-talk between TJ and anchoring junction to allow simultaneous maintenance of the BTB and germ cell movement across the seminiferous epithelium.
Nitric oxide and cyclic nucleotides: their roles in junction dynamics and spermatogenesis.
Adv Exp Med Biol. 2008; 636: 172-85
Lee NP, Cheng CY
Spermatogenesis is a highly complicated process in which functional spermatozoa (haploid, 1n) are generated from primitive mitotic spermatogonia (diploid, 2n). This process involves the differentiation and transformation of several types of germ cells as spermatocytes and spermatids undergo meiosis and differentiation. Due to its sophistication and complexity, testis possesses intrinsic mechanisms to modulate and regulate different stages of germ cell development under the intimate and indirect cooperation with Sertoli and Leydig cells, respectively. Furthermore, developing germ cells must translocate from the basal to the apical (adluminal) compartment of the seminiferous epithelium. Thus, extensive junction restructuring must occur to assist germ cell movement. Within the seminiferous tubules, three principal types of junctions are found namely anchoring junctions, tight junctions, and gap junctions. Other less studied junctions are desmosome-like junctions and hemidesmosome junctions. With these varieties of junction types, testes are using different regulators to monitor junction turnover. Among the uncountable junction modulators, nitric oxide (NO) is a prominent candidate due to its versatility and extensive downstream network. NO is synthesized by nitric oxide synthase (NOS). Three traditional NOS, specified as endothelial NOS (eNOS), inducible NOS (iNOS), and neuronal NOS (nNOS), and one testis-specific nNOS (TnNOS) are found in the testis. For these, eNOS and iNOS were recently shown to have putative junction regulation properties. More important, these two NOSs likely rely on the downstream soluble guanylyl cyclase/cGMP/protein kinase G signaling pathway to regulate the structural components at the tight junctions and Adherens junctions in the testes. Apart from the involvement in junction regulation, NOS/NO also participates in controlling the levels of cytokines and hormones in the testes. On the other hand, NO is playing a unique role in modulating germ cell viability and development, and indirectly acting on some aspects of male infertility and testicular pathological conditions. Thus, NOS/NO bears an irreplaceable role in maintaining the homeostasis of the microenvironment in the seminiferous epithelium via its different downstream signaling pathways.
Cell Microbiol. 2009 Oct 13;
Geny B, Grassart A, Manich M, Chicanne G, Payrastre B, Sauvonnet N, Popoff MR
Summary Inactivation of different small GTPases upon their glucosylation by lethal toxin from Clostridium sordellii strain IP82 (LT-82) is already known to lead to cell rounding, Adherens junction (AJ) disorganization, and actin depolymerization. In the present work, we observed that LT-82 induces a rapid dephosphorylation of paxillin, a protein regulating focal adhesion (FA), independently of inactivation of paxillin kinases such as Src, Fak and Pyk2. Amongst the small GTPases inactivated by this toxin, including Rac, Ras, Rap and Ral, we identified Rac1, as responsible for paxillin dephosphorylation using cells overexpressing Rac1(V12). Rac1 inactivation by LT-82 modifies interactions between proteins from AJ and FA complexes as shown by pull down assays. We showed that in Triton X-100 insoluble membrane proteins from these complexes, namely E-cadherin, beta-catenin, p120-catenin, and talin, are decreased upon LT-82 intoxication, a treatment that also induces a rapid decrease in cell phosphoinositide content. Therefore, we proposed that Rac inactivation by LT-82 alters phosphoinositide metabolism leading to FA and AJ complex disorganization and actin depolymerization.