title: Mutant presenilin (A260V) affects Rab8 in PC12D cell.
abstract: Most familial early-onset Alzheimer's disease (FAD) is caused by mutations in the presenilin-1 (PS1) gene. Abeta is derived from amyloid precursor protein (APP) and an increased concentration of Abeta 42 is widely believed to be a pathological hallmark of abnormal PS function. Therefore, the interaction between PS1 and APP is a central theme in attempts to clarify the molecular mechanism of AD. To examine the effect of PS1 mutations on APP metabolism, we made PC12D cell lines that express human PS1 or mutant PS1 (A260V). In PC12D cells expressing the PS1A260V mutant, we found that Rab8, a GTPase involved in transport from the trans-Golgi network (TGN) to the plasma membrane (PM), was significantly reduced in PC12D cells expressing the A260V mutant and that APP C-terminal fragment (CTF), the direct precursor of Abeta, accumulated in the heavy membrane fraction including membrane vesicles involved in TGN-to-PM transport. Furthermore, the total intracellular Abeta production was reduced in these cells. Combined together, we have observed that PS1 mutation disturbs membrane vesicle transport, resulting in prolonged residence of APP CTF during TGN-to-PM transport pathway. Therefore, it is highly likely that reduction of Abeta is closely related to the retention of APP CTF during TGN-to-PM transport.
authors.affiliation: Department of Molecular Neurobiology, Tokyo Institute of Psychiatry, 2-1-8 Kamikitazawa, Setagayaku, Tokyo 156-8585, Japan. kametani@prit.go.jp
authors.forename: Fuyuki
authors.initials: F
authors.lastname: Kametani
authors.forename: Mihoko
authors.initials: M
authors.lastname: Usami
authors.forename: Kikuko
authors.initials: K
authors.lastname: Tanaka
authors.forename: Hideaki
authors.initials: H
authors.lastname: Kume
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Mori
mesh_terms: D016564:Amyloid beta-Protein Precursor / Q000378:metabolism; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D003287:Contrast Media; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D015151:Immunoblotting; D008565:Membrane Proteins / Q000235:genetics* / Q000494:pharmacology*; D009154:Mutation / Q000502:physiology; D016501:Neurites / Q000187:drug effects; D016716:PC12 Cells; D053764:Presenilin-1; D051381:Rats; D013347:Subcellular Fractions / Q000187:drug effects / Q000378:metabolism; D014162:Transfection; D014283:Triiodobenzoic Acids; D020691:rab GTP-Binding Proteins / Q000235:genetics* / Q000502:physiology*; D021601:trans-Golgi Network / Q000378:metabolism
chemical_list: D016564:Amyloid beta-Protein Precursor; D003287:Contrast Media; D008565:Membrane Proteins; C508853:PSEN1 protein, human; D053764:Presenilin-1; D014283:Triiodobenzoic Acids; C082377:RAB8A protein, human; C513177:Rab8b protein, rat; D020691:rab GTP-Binding Proteins; C044834:iodixanol