title: PrP octarepeats region determined the interaction with caveolin-1 and phosphorylation of caveolin-1 and Fyn.
abstract: Caveolin-1 is one of the major constituents of caveolae. Both Cav-1 and PrP are plasma membrane proteins, which show active capacities for molecular interactions with many other proteins or agents, including themselves. Using yeast two-hybrid system and immunoprecipitation, we reconfirmed the molecular interaction between human Cav-1 and PrP. With co-immunoprecipitation tests, PrP(C)-Cav-1 and PrP(Sc)-Cav-1 complexes were identified in the brain homogenates of normal and scrapie agent 263K-infected hamsters, respectively. Transient expression of wild-type PrP (PrP-PG5) in HEK293 cells did not change the situation of Cav-1 and subsequent signal transduction pathways, while cross-linking of the expressed PrP with specific antibody induced remarkable colocalization of PrP and Cav-1 on the plasma membrane and significant increases of phosphorylated Cav-1 and phosphorylated Fyn. With deleted and inserted PrP mutants within octarepeat region, we observed obvious octarepeat-associated phenomena, including lower binding capacity with Cav-1 in vitro, unable to co-localize with Cav-1 in the cells and to induce up-regulation of p-Cav-1 and p-Fyn when removal of octarepeats in the context of full-length PrP. Moreover, we found that treatment on HEK293 cells with fibrous form of recombinant PrP protein led to up-regulating the levels of p-Cav-1 and p-Fyn. Our data here provide strong evidence that octarepeats of PrP are critical for the interaction between PrP and Cav-1. Significant alterations in the cultured cells, either the distributions of PrP and Cav-1 morphologically or the up-regulations of p-Cav-1 and p-Fyn, induced by antibody-mediated cross-linking or fibrous forms of PrP may suggest a possible internalization process of PrP(Sc).
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing 102206, People's Republic of China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Shi
authors.forename: Yuan-Yuan
authors.initials: YY
authors.lastname: Jing
authors.forename: Shao-Bin
authors.initials: SB
authors.lastname: Wang
authors.forename: Cao
authors.initials: C
authors.lastname: Chen
authors.forename: Han
authors.initials: H
authors.lastname: Sun
authors.forename: Yin
authors.initials: Y
authors.lastname: Xu
authors.forename: Chen
authors.initials: C
authors.lastname: Gao
authors.forename: Jin
authors.initials: J
authors.lastname: Zhang
authors.forename: Chan
authors.initials: C
authors.lastname: Tian
authors.forename: Yan
authors.initials: Y
authors.lastname: Guo
authors.forename: Ke
authors.initials: K
authors.lastname: Ren
authors.forename: Xiao-Ping
authors.initials: XP
authors.lastname: Dong
mesh_terms: D000818:Animals; D001921:Brain / Q000473:pathology; D051242:Caveolin 1 / Q000378:metabolism*; D002460:Cell Line; D006224:Cricetinae; D004252:DNA Mutational Analysis; D006801:Humans; D047468:Immunoprecipitation; D008647:Mesocricetus; D050505:Mutant Proteins / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D011328:Prions / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D051076:Proto-Oncogene Proteins c-fyn / Q000378:metabolism; D020449:Repetitive Sequences, Amino Acid; D020798:Two-Hybrid System Techniques
chemical_list: C495540:CAV1 protein, human; D051242:Caveolin 1; D050505:Mutant Proteins; D011328:Prions; C494957:FYN protein, human; D051076:Proto-Oncogene Proteins c-fyn