BIOC 212 Lecture Notes - Lecture 9: Guanine, Vesicle Fusion, Phenylalanine
Document Summary
Sar1 and arf: cop vesicle initiation: ras: signal transduction, rab: vesicle targeting, ran: nuclear import & export, gtpase activating proteins (gap, stimulate gtp hydrolysis, guanine exchange factors (gef, cause release of gdp and binding of gtp. Sar1-gtp exposes amphipathic helix and partially inserts into membrane, to initiate vesicle formation. Cop ii coat formation hydrolysis the er: adaptor proteins (sec23 and sec24) bind activated sar1 (has binding sites for cargo proteins) and. In gdp bound state sar1 doesn"t bind adaptor coat proteins don"t bind and the whole coat dissociates un-coating: adaptors separate from sar1 and coat separates from adaptors. No adaptor = stuck in gtp bound state: uncoating is necessary for vesicle fusion at golgi (thickness of the membrane is too much for the vesicle to bud off) Er adaptor: asp-x-glu (dxe) within a sequence, recognized by sec23/24 adaptor, lumenal proteins are recognized by various cargo receptors, which are tm proteins with exit signals (ff)