Kegg Pathway: Prion disease

EMBO J. 2009 Nov 19;
Lee S, Antony L, Hartmann R, Knaus KJ, Surewicz K, Surewicz WK, Yee VC

A conformational transition of normal cellular Prion protein (PrP(C)) to its pathogenic form (PrP(Sc)) is believed to be a central event in the transmission of the devastating neurological diseases known as spongiform encephalopathies. The common methionine/valine polymorphism at residue 129 in the PrP influences disease susceptibility and phenotype. We report here seven crystal structures of human PrP variants: three of wild-type (WT) PrP containing V129, and four of the familial variants D178N and F198S, containing either M129 or V129. Comparison of these structures with each other and with previously published WT PrP structures containing M129 revealed that only WT PrPs were found to crystallize as domain-swapped dimers or closed monomers; the four mutant PrPs crystallized as non-swapped dimers. Three of the four mutant PrPs aligned to form intermolecular beta-sheets. Several regions of structural variability were identified, and analysis of their conformations provides an explanation for the structural features, which can influence the formation and conformation of intermolecular beta-sheets involving the M/V129 polymorphic residue.

CNS Neurol Disord Drug Targets. 2009 Nov; 8(5): 315
Appleby BS

N Engl J Med. 2009 Nov 19; 361(21): 2056-2065
Mead S, Whitfield J, Poulter M, Shah P, Uphill J, Campbell T, Al-Dujaily H, Hummerich H, Beck J, Mein CA, Verzilli C, Whittaker J, Alpers MP, Collinge J

BACKGROUND: Kuru is a devastating epidemic Prion disease that affected a highly restricted geographic area of the Papua New Guinea highlands; at its peak, it predominantly affected adult women and children of both sexes. Its incidence has steadily declined since the cessation of its route of transmission, endocannibalism. METHODS: We performed genetic and selected clinical and genealogic assessments of more than 3000 persons from Eastern Highland populations, including 709 who participated in cannibalistic mortuary feasts, 152 of whom subsequently died of kuru. RESULTS: Persons who were exposed to kuru and survived the epidemic in Papua New Guinea are predominantly heterozygotes at the known resistance factor at codon 129 of the Prion protein gene (PRNP). We now report a novel PRNP variant - G127V - that was found exclusively in people who lived in the region in which kuru was prevalent and that was present in half of the otherwise susceptible women from the region of highest exposure who were homozygous for methionine at PRNP codon 129. Although this allele is common in the area with the highest incidence of kuru, it is not found in patients with kuru and in unexposed population groups worldwide. Genealogic analysis reveals a significantly lower incidence of kuru in pedigrees that harbor the protective allele than in geographically matched control families. CONCLUSIONS: The 127V polymorphism is an acquired Prion disease resistance factor selected during the kuru epidemic, rather than a pathogenic mutation that could have triggered the kuru epidemic. Variants at codons 127 and 129 of PRNP demonstrate the population genetic response to an epidemic of Prion disease and represent a powerful episode of recent selection in humans. Copyright 2009 Massachusetts Medical Society.

Nippon Ronen Igakkai Zasshi. 2009; 46(5): 458-461
Kamogawa K, Toi T, Okamoto K, Okuda B

A 79-year-old woman was admitted to our hospital, due to acute onset of left hemiparesis and disturbance of consciousness. Although her symptoms improved temporarily, she developed gait disturbance and cognitive deterioration 2 months after the onset. After that, she presented with myoclonus and startle response, followed by akinetic mutism within 8 months after the onset. Serial EEGs revealed no periodic synchronous discharge. Serial diffusion-weighted MRIs showed that high intensity lesions, which initially limited to the right cerebral cortex, gradually spread to the bilateral cerebral cortices and basal ganglia, with relative sparing of central gyri, medial occipital cortices, and hippocampus. Prion protein gene analysis revealed a point mutation (Val-->Ile) at codon 180. The result of this patient suggests that this type of CJD might be associated with an atypical clinical course such as stroke-like episode and selective involvement of cortical and subcortical resions.

J Neurochem. 2009 Nov 16;
Seo JS, Seol JW, Moon MH, Jeong JK, Lee YJ, Park SY

Prion diseases are neurodegenerative disorders characterized by the accumulation of an abnormal isoform of the Prion protein PrP(Sc). Human Prion protein (HuPrP) fragment, PrP (106-126), may contain most of the pathological features associated with PrP(Sc). Hypoxic conditions elicit cellular responses adaptively designed to improve cell survival and have an important role in the process of cell survival. We investigate the effects of hypoxia on PrP (106-126)-induced apoptosis in the present study. Human neuroblastoma and glioblastoma cells were incubated with varied doses of PrP (106-126) under both normoxic or hypoxic conditions, in order to determine the regulatory effects of hypoxia on PrP (106-126)-induced apoptosis. The results indicate that hypoxia protects neuronal cells against PrP (106-126)-induced cell death by activating the Akt signal, which is inactivated by Prion proteins, and inhibiting PrP (106-126)-induced caspase-3 activation. Low oxygen conditions increase the Bcl-2 protein, which is associated with anti-apoptotic signals, and recover the PrP (106-126)-induced reduction in mitochondrial transmembrane potential (MTP). This study demonstrates that hypoxia inhibits PrP (106-126)-induced neuron cell death by regulating Akt and Akt-related signaling, and it also suggests that Prion-related neuronal damage and disease may be regulated by hypoxia or by hypoxic-inducing genes.

J Neuropathol Exp Neurol. 2009 Oct; 68(10): 1125-35
Lewis V, Hill AF, Haigh CL, Klug GM, Masters CL, Lawson VA, Collins SJ

Prion disease pathogenesis is linked to the cell-associated propagation of misfolded protease-resistant conformers (PrP) of the normal cellular Prion protein (PrP). Ongoing PrP expression is the only known absolute requirement for successful Prion disease transmission and PrP propagation. Further typifying Prion disease is selective neuronal dysfunction and loss, although the precise mechanisms underlying this are undefined. We utilized a single Prion strain (M1000) and a range of neuronal and nonneuronal, PrP endogenously expressing and transgenically modified overexpressing cell lines, to evaluate whether PrP glycosylation patterns or constitutive N-terminal cleavage events may be determinants of sustained PrP propagation. Our data demonstrates that relative proportions of full-length and C1 truncated PrP are the most important characteristics influencing susceptibility to sustained M1000 Prion infection, supporting PrP alpha-cleavage as a protective event, which may contribute to the selective neuronal vulnerability observed in vivo.

J Neurol Neurosurg Psychiatry. 2009 Dec; 80(12): 1386-9
Jansen C, van Swieten JC, Capellari S, Strammiello R, Parchi P, Rozemuller AJ

An atypical case of inherited Creutzfeldt-Jakob disease (CJD) is described in a 35-year-old Dutch woman, homozygous for methionine at codon 129 of the Prion protein gene (PRNP). The clinical phenotype was characterised by slowly progressive cognitive decline and parkinsonism. Neuropathological findings consisted of scanty spongiosis and only faint to absent immunohistochemical staining for the abnormal Prion protein, PrP(Sc), with patchy deposits in the cerebellar cortex. Purkinje cells were abnormally located in the molecular layer of the cerebellum. Western blot analysis showed the co-occurrence of PrP(Sc) types 1 and 2 with an unusual distribution. Sequence analysis disclosed a novel 120 bp insertion in the octapeptide repeat region of the PRNP, encoding five additional R2 octapeptide repeats. These features define an unusual neuropathological phenotype and novel genotype, further expanding the spectrum of genotype-phenotype correlations in inherited Prion diseases and emphasising the need to carry out pre-mortem PRNP sequencing in all young patients with atypical dementias.

Anim Genet. 2009 Nov 16;
Msalya G, Shimogiri T, Nishitani K, Okamoto S, Kawabe K, Minesawa M, Maeda Y

Genetic differences which exist in the Prion protein gene (PRNP) have been reported to influence susceptibility of humans, sheep and goats to Prion diseases. In cattle, however, none of the known coding polymorphisms has a direct effect on bovine spongiform encephalopathy (BSE). It has been reported that 23-bp insertion/deletion (indel) polymorphisms within the promoter region have a tentative association to BSE susceptibility in German cattle, and a lower number of 24-bp repeat units in the open reading frame (ORF) was reported to reduce BSE susceptibility in transgenic mice. In this study, because of the hypothesis that bovine PRNP promoter polymorphisms cause changes in PRNP expression, we genotyped PRNP polymorphisms in the promoter and intron 1 using 218 genomic DNA samples from two Japanese cattle breeds. We also analysed the expression levels of Prion in 40 animals by quantification of real-time PCR using mRNAs extracted from the medulla oblongata to study the relationship between PRNP genotypes and PRNP expression. We found a significant correlation between promoter indel polymorphisms and PRNP-mRNA expression (P(0.0413)) and therefore hypothesize that differences in polymorphisms could be one of the causes of differences in PRNP expression levels. We also report a novel difference in PRNP expression (P < 0.0001) between Japanese Black and Japanese Brown cattle breeds. There was no significant difference based on age and sex of the animals.

Anim Genet. 2009 Nov 16;
Lampo E, Duchateau L, Schepens B, Van Poucke M, Saelens X, Erkens T, Van Zeveren A, Peelman LJ

Shadow of Prion protein (SPRN) is an interesting candidate gene thought to be involved in Prion pathogenesis. In humans, an association has already been discovered between mutations in SPRN and the incidence of variant and sporadic Creutzfeldt-Jakob disease. However, in sheep, the effect of mutations in SPRN is largely unknown. Therefore, we analysed the presence of mutations in the entire ovine SPRN gene, their association with scrapie susceptibility and their effect on SPRN promoter activity. In total, 26 mutations were found: seven in the promoter region, four in intron 1, seven in the coding sequence and eight in the 3' untranslated region. The mutations detected in the coding sequence and the promoter region were subsequently analysed in more detail. In the coding sequence, a polymorphism causing a deletion of two alanines was found to be associated with susceptibility for classical scrapie in sheep. Furthermore, a functional analysis of deletion constructs of the ovine SPRN promoter revealed that the region 464 to 230 bp upstream of exon 1 (containing a putative AP-2 and putative Sp1 binding sites) is of functional importance for SPRN transcription. Six mutations in the SPRN promoter were also found to alter the promoter activity in vitro. However, no association between any of these promoter mutations and susceptibility for classical scrapie was found.

PLoS One. 2009; 4(11): e7816
Biasini E, Tapella L, Mantovani S, Stravalaci M, Gobbi M, Harris DA, Chiesa R

BACKGROUND: Prion diseases are fatal neurodegenerative disorders that can arise sporadically, be genetically inherited or acquired through infection. The key event in these diseases is misfolding of the cellular Prion protein (PrP(C)) into a pathogenic isoform that is rich in beta-sheet structure. This conformational change may result in the formation of PrP(Sc), the Prion isoform of PrP, which propagates itself by imprinting its aberrant conformation onto PrP(C) molecules. A great deal of effort has been devoted to developing protocols for purifying PrP(Sc) for structural studies, and testing its biological properties. Most procedures rely on protease digestion, allowing efficient purification of PrP27-30, the protease-resistant core of PrP(Sc). However, protease treatment cannot be used to isolate abnormal forms of PrP lacking conventional protease resistance, such as those found in several genetic and atypical sporadic cases. PRINCIPAL FINDINGS: We developed a method for purifying pathological PrP molecules based on sequential centrifugation and immunoprecipitation with a monoclonal antibody selective for aggregated PrP. With this procedure we purified full-length PrP(Sc) and mutant PrP aggregates at electrophoretic homogeneity. PrP(Sc) purified from Prion-infected mice was able to seed misfolding of PrP(C) in a protein misfolding cyclic amplification reaction, and mutant PrP aggregates from transgenic mice were toxic to cultured neurons. SIGNIFICANCE: The immunopurification protocol described here isolates biologically active forms of aggregated PrP. These preparations may be useful for investigating the structural and chemico-physical properties of infectious and neurotoxic PrP aggregates.

Nat Chem Biol. 2009 Dec; 5(12): 936-46
Roberts BE, Duennwald ML, Wang H, Chung C, Lopreiato NP, Sweeny EA, Knight MN, Shorter J

Safely eradicating Prions, amyloids and preamyloid oligomers may ameliorate several fatal neurodegenerative disorders. Yet whether small-molecule drugs can directly antagonize the entire spectrum of distinct amyloid structures or 'strains' that underlie distinct disease states is unclear. Here, we investigated this issue using the yeast Prion protein Sup35. We have established how epigallocatechin-3-gallate (EGCG) blocks synthetic Sup35 Prionogenesis, eliminates preformed Sup35 Prions and disrupts inter- and intramolecular Prion contacts. Unexpectedly, these direct activities were strain selective, altered the repertoire of accessible infectious forms and facilitated emergence of a new Prion strain that configured original, EGCG-resistant intermolecular contacts. In vivo, EGCG cured and prevented induction of susceptible, but not resistant strains, and elicited switching from susceptible to resistant forms. Importantly, 4,5-bis-(4-methoxyanilino)phthalimide directly antagonized EGCG-resistant Prions and synergized with EGCG to eliminate diverse Sup35 Prion strains. Thus, synergistic small-molecule combinations that directly eradicate complete strain repertoires likely hold considerable therapeutic potential.

Proc Natl Acad Sci U S A. 2009 Nov 13;
Colby DW, Giles K, Legname G, Wille H, Baskakov IV, Dearmond SJ, Prusiner SB

Prions are infectious proteins that encipher biological information within their conformations; variations in these conformations dictate different Prion strains. Toward elucidating the molecular language of Prion protein (PrP) conformations, we produced an array of recombinant PrP amyloids with varying conformational stabilities. In mice, the most stable amyloids produced the most stable Prion strains that exhibited the longest incubation times, whereas more labile amyloids generated less stable strains and shorter incubation times. The direct relationship between stability and incubation time of Prion strains suggests that labile Prions are more fit, in that they accumulate more rapidly and thus kill the host faster. Although incubation times can be changed by altering the PrP expression level, PrP sequence, Prion dose, or route of inoculation, we report here the ability to modify the incubation time predictably in mice by modulating the Prion conformation.

Biochem Biophys Res Commun. 2009 Nov 12;
Hillmer AS, Putcha P, Levin J, Högen T, Hyman BT, Kretzschmar H, McLean PJ, Giese A

Intracellular alpha-synuclein (alpha-syn) aggregates are the pathological hallmark in several neurodegenerative diseases including Parkinson's disease, dementia with Lewy bodies and multiple system atrophy. Recent evidence suggests that small oligomeric aggregates rather than large amyloid fibrils represent the main toxic particle species in these diseases. We recently characterized iron-dependent toxic alpha-syn oligomer species by confocal single molecule fluorescence techniques and used this aggregation model to identify several N -benzylidene-benzohydrazide (NBB) derivatives inhibiting oligomer formation in vitro. In our current work, we used the bioluminescent protein-fragment complementation assay (BPCA) to directly analyze the formation of toxic alpha-syn oligomers in cell culture and to investigate the effect of iron and potential drug-like compounds in living cells. Similar to our previous findings in vitro, we found a converse modulation of toxic alpha-syn oligomers by NBB derivates and ferric iron, which was characterized by an increase in aggregate formation by iron and an inhibitory effect of certain NBB compounds. Inhibition of alpha-syn oligomer formation by the NBB compound 293G02 was paralleled by a reduction in cytotoxicity indicating that toxic alpha-syn oligomers are present in the BPCA cell culture model and that pharmacological inhibition of oligomer formation can reduce toxicity. Thus, this approach provides a suitable model system for the development of new disease-modifying drugs targeting toxic oligomer species. Moreover, NBB compounds such as 293G02 may provide useful tool compounds to dissect the functional role of toxic oligomer species in cell culture models and in vivo.

J Mol Biol. 2009 Nov 10;
Taubner LM, Bienkiewicz EA, Copié V, Caughey B

The intrinsically disordered amino-proximal domain of hamster Prion protein (PrP) contains four copies of a highly conserved octapeptide sequence, PHGGGWGQ, that is flanked by two polycationic residue clusters. This N-terminal domain mediates the binding of sulfated glycans, which can profoundly influence the conversion of PrP to pathological forms and the progression of Prion disease. To investigate the structural consequences of sulfated glycan binding, we performed multidimensional heteronuclear ((1)H, (13)C, (15)N) NMR (nuclear magnetic resonance), circular dichroism (CD), and fluorescence studies on hamster PrP residues 23-106 (PrP 23-106) and fragments thereof when bound to pentosan polysulfate (PPS). While the majority of PrP 23-106 remain disordered upon PPS binding, the octarepeat region adopts a repeating loop-turn structure that we have determined by NMR. The beta-like turns within the repeats are corroborated by CD data demonstrating that these turns are also present, although less pronounced, without PPS. Binding to PPS exposes a hydrophobic surface composed of aligned tryptophan side chains, the spacing and orientation of which are consistent with a self-association or ligand binding site. The unique tryptophan motif was probed by intrinsic tryptophan fluorescence, which displayed enhanced fluorescence of PrP 23-106 when bound to PPS, consistent with the alignment of tryptophan side chains. Chemical-shift mapping identified binding sites on PrP 23-106 for PPS, which include the octarepeat histidine and an N-terminal basic cluster previously linked to sulfated glycan binding. These data may in part explain how sulfated glycans modulate PrP conformational conversions and oligomerizations.

J Anim Breed Genet. 2009 Dec; 126(6): 463-7
Oztabak K, Ozkan E, Soysal I, Paya I, Un C

Bovine spongiform encephalopathy (BSE) is a fatal disease caused by miss folded Prion protein. Studies in the cattle, comparing genetic data from BSE diseased and healthy animals have shown that indel polymorphisms in the promoter and intron 1 of PRNP gene were associated with disease susceptibility. Several studies were conducted to find out allele and genotypic frequencies of indel polymorphisms in promoter and intron 1 of the cattle PRNP gene. Unlike domestic cattle and bison, no indel polymorphisms of the PRNP promoter and intron 1 were examined in any population of the water buffalo (Bubalus bubalis). Aim of this study was to analyse frequencies of allele, genotype, and haplotype of the indel polymorphisms (23 bp indel in promoter and 12 bp indel in intron 1) in Prion protein coding gene (PRNP) of water buffalo. Therefore a PCR based procedure, previously used in cattle to detect indel polymorphisms of PRNP promoter and intron 1 locus, was applied to 106 Anatolian water buffalo DNAs. Our results have revealed high frequency of in variants and in23/in12 haplotype for PRNP promoter and intron 1 indel polymorphisms in water buffalo. The results of the study have demonstrated that frequencies of allele, genotype, and haplotype of the indel polymorphisms in PRNP gene of the Anatolian water buffalo are significantly different those from cattle and bison PRNP indel polymorphisms.

J Am Vet Med Assoc. 2009 Nov 15; 235(10): 1171-9
Ridpath JF, Fulton RW

Acta Neuropathol. 2009 Nov 13;
Jansen C, Parchi P, Capellari S, Vermeij AJ, Corrado P, Baas F, Strammiello R, van Gool WA, van Swieten JC, Rozemuller AJ

Stop codon mutations in the gene encoding the Prion protein (PRNP) are very rare and have thus far only been described in two patients with Prion protein cerebral amyloid angiopathy (PrP-CAA). In this report, we describe the clinical, histopathological and pathological Prion protein (PrP(Sc)) characteristics of two Dutch patients carrying novel adjacent stop codon mutations in the C-terminal part of PRNP, resulting in either case in hereditary Prion protein amyloidoses, but with strikingly different clinicopathological phenotypes. The patient with the shortest disease duration (27 months) carried a Y226X mutation and showed PrP-CAA without any neurofibrillary lesions, whereas the patient with the longest disease duration (72 months) had a Q227X mutation and showed an unusual Gerstmann-Sträussler-Scheinker disease phenotype with numerous cerebral multicentric amyloid plaques and severe neurofibrillary lesions without PrP-CAA. Western blot analysis in the patient with the Q227X mutation demonstrated the presence of a 7 kDa unglycosylated PrP(Sc) fragment truncated at both the N- and C-terminal ends. Our observations expand the spectrum of clinicopathological phenotypes associated with PRNP mutations and show that a single tyrosine residue difference in the PrP C-terminus may significantly affect the site of amyloid deposition and the overall phenotypic expression of the Prion disease. Furthermore, it confirms that the absence of the glycosylphosphatidylinositol anchor in PrP predisposes to amyloid plaque formation.

J Allergy Clin Immunol. 2009 Nov 10;
Mathias RA, Grant AV, Rafaels N, Hand T, Gao L, Vergara C, Tsai YJ, Yang M, Campbell M, Foster C, Gao P, Togias A, Hansel NN, Diette G, Adkinson NF, Liu MC, Faruque M, Dunston GM, Watson HR, Bracken MB, Hoh J, Maul P, Maul T, Jedlicka AE, Murray T, Hetmanski JB, Ashworth R, Ongaco CM, Hetrick KN, Doheny KF, Pugh EW, Rotimi CN, Ford J, Eng C, Burchard EG, Sleiman PM, Hakonarson H, Forno E, Raby BA, Weiss ST, Scott AF, Kabesch M, Liang L, Abecasis G, Moffatt MF, Cookson WO, Ruczinski I, Beaty TH, Barnes KC

BACKGROUND: Asthma is a complex disease characterized by striking ethnic disparities not explained entirely by environmental, social, cultural, or economic factors. Of the limited genetic studies performed on populations of African descent, notable differences in susceptibility allele frequencies have been observed. OBJECTIVES: We sought to test the hypothesis that some genes might contribute to the profound disparities in asthma. METHODS: We performed a genome-wide association study in 2 independent populations of African ancestry (935 African American asthmatic cases and control subjects from the Baltimore-Washington, DC, area and 929 African Caribbean asthmatic subjects and their family members from Barbados) to identify single-nucleotide polymorphisms (SNPs) associated with asthma. RESULTS: A meta-analysis combining these 2 African-ancestry populations yielded 3 SNPs with a combined P value of less than 10(-5) in genes of potential biologic relevance to asthma and allergic disease: rs10515807, mapping to the alpha-1B-adrenergic receptor (ADRA1B) gene on chromosome 5q33 (3.57 x 10(-6)); rs6052761, mapping to the Prion-related protein (PRNP) gene on chromosome 20pter-p12 (2.27 x 10(-6)); and rs1435879, mapping to the dipeptidyl peptidase 10 (DPP10) gene on chromosome 2q12.3-q14.2. The generalizability of these findings was tested in family and case-control panels of United Kingdom and German origin, respectively, but none of the associations observed in the African groups were replicated in these European studies. Evidence for association was also examined in 4 additional case-control studies of African Americans; however, none of the SNPs implicated in the discovery population were replicated. CONCLUSIONS: This study illustrates the complexity of identifying true associations for a complex and heterogeneous disease, such as asthma, in admixed populations, especially populations of African descent.

J Neurosci. 2009 Nov 11; 29(45): 14108-19
Biscaro B, Lindvall O, Hock C, Ekdahl CT, Nitsch RM

The hippocampus is heavily affected by progressive neurodegeneration and beta-amyloid pathology in Alzheimer's disease (AD). The hippocampus is also one of the few brain regions that generate new neurons throughout adulthood. Because hippocampal neurogenesis is regulated by both endogenous and environmental factors, we determined whether it benefits from therapeutic reduction of beta-amyloid peptide (Abeta)-related toxicity induced by passive Abeta immunotherapy. Abeta immunotherapy of 8-9-month-old mice expressing familial AD-causing mutations in the amyloid precursor protein and presenilin-1 genes with an antibody against Abeta decreased compact beta-amyloid plaque burden and promoted survival of newly born neurons in the hippocampal dentate gyrus. As these neurons matured, they exhibited longer dendrites with more complex arborization compared with newly born neurons in control-treated transgenic littermates. The newly born neurons showed signs of functional integration indicated by expression of the immediate-early gene Zif268 in response to exposure to a novel object. Abeta immunotherapy was associated with higher numbers of synaptophysin-positive synaptic boutons. Labeling dividing progenitor cells with a retroviral vector encoding green fluorescent protein (GFP) showed that Abeta immunotherapy restored the impaired dendritic branching, as well as the density of dendritic spines in new mature neurons. The presence of cellular Prion protein (PrP(c)) on the dendrites of the GFP(+) newly born neurons is compatible with a putative role of PrP(c) in mediating Abeta-related toxicity in these cells. In addition, passive Abeta immunotherapy was accompanied by increased angiogenesis. Our data establish that passive Abeta immunotherapy can restore the morphological maturation of the newly formed neurons in the adult hippocampus and promote angiogenesis. These findings provide evidence for a role of Abeta immunotherapy in stimulating neurogenesis and angiogenesis in transgenic mouse models of AD, and they suggest the possibility that Abeta immunotherapy can recover neuronal and vascular functions in brains with beta-amyloidosis.

Acta Biochim Biophys Sin (Shanghai). 2009 Nov; 41(11): 929-37
Li X, Dong C, Shi S, Wang G, Li Y, Wang X, Shi Q, Tian C, Zhou R, Gao C, Dong X

Prion protein (PrP) is considered to associate with microtubule and its major component, tubulin. In the present study, octarepeat region of PrP (PrP51-91) was expressed in prokaryotic-expressing system. Using GST pull-down assay and co-immunoprecipitation, the molecular interaction between PrP51-91 and tubulin was observed. Our data also demonstrated that PrP51-91 could efficiently stimulate microtubule assembly in vitro, indicating a potential effect of PrP on microtubule dynamics. Moreover, PrP51-91 was confirmed to be able to antagonize Cu(2+)-induced microtubule-disrupting activity in vivo, partially protecting against Cu(2+) intoxication to culture cells and stabilize cellular microtubule structure. The association of the octarepeat region of PrP with tubulin may further provide insight into the biological function of PrP in the neurons.