protein targeting and export 5 Flashcards
vesicles have coats of proteins which are
COP
what do COPs do
reshape membrane to curve/bud determines size/shape of vesicle concentrate in vesicle provides selectivity for cargo determine final destination
how do COPs differ
type of vesicle
what else do they contain
GTP binding protein
V snare
once made and budded vesicles need to be
uncoated to expose the V-snare
v snare to
t snare
clathrin coated vesicles go from what to what
trans golgi network TGN to
endosome and plasma
COP 1 go from what to what
golgi to
ER
cop 2 goes from what to what
ER to
golgi
clathrin subunits are made of what
3 large and
3 small polypeptides
which forms triskelions in the TGN
assembly of clathrin coat
cargo binds to mannose-6-p receptor (selective)
also binds adaptin, which binds triskelions
coat forms
formation and budding assisted by dynamin (GTP)
coat dissociates immediately after
what does dynamin form
forms a helical ring around the neck of the bud and recruits other proteins to help bring the 2 lipids together
Ts mutants of dynamin does what
halts its process and allows visualization of the budding
COP 2 what is it made of
5 protein subunits and
GTPase sar 1
what does COP 2 recruit
enzymes for golgi processing (glycosyltransferase)
docking and fusion proteins
integral proteins that bind to specific cargo
COP 1 retrieve proteins from
golgi to ER
COP 1
what do ER proteins have
KDEL at C-terminal
recognised by KDEL receptor
importance of GTPase
each type of coating has specific GTPase
GTP hydrolysis cause conformational change
what happens when NON hydrolysable GTP analogues are added to these GTPases
all types of coats accumalate
because GTPase hydrolysis is required for disassembly
dynamin is a GTPase, so budding cant be completed
GTPase is involved in vesicle targeting
