L11 Vesicular Trafficking I Flashcards
What types of SNAREs are there
v-SNAREs and t-SNAREs
What are transport vesicles coated in?
Clathrin, COPI & COPII
What is a paradigm for transport vesicle formation
COPII coated vesicle
What associates with the rough ER
ribosomes
How are newly made proteins translocated into organelles
co-translationally or post-translationally
What does translocation into the ER require
signal
How are membrane proteins inserted into the ER
signal peptidase
What ensures proper protein folding in the ER
chaperones
What do defects in protein folding give rise to
disease
What do misfolded proteins stimulate?
unfolded protein response
What are the essential components for all transport vesicle formation
GTPase, adaptor proteins, and coat
What act as molecular switches
GTPases
What converts GDP to GTP
guanine nucleotide exchange factors
What converts GTP to GDP
GTPase activating proteins
Where is GDP form usually found
cytosol
Where is GTP form usually found
membrane
What is the main member of GTPases
Ras
What is the GTPase component of COPII
Sar1
What is the adaptor component of COPII
Sec23/24
What is the coat component of COPII
Sec13/31
Adaptor protein function
recognise and select cargo ensuring specificity
What do adaptor proteins recognise
motifs in cytoplasmic domains
AP2
major clathrin adaptor
What is AP2 involved in
endocytosis
What do coat proteins provide
structural scaffold
What experiments allow us to understand what makes a COPII vesicle
reconstitution experiments
Ribophorin
resident ER protein
P58
COPII cargo protein
Where are GTPases recruited from
cytosol
GTP mutant
cannot hydrolyse GTP
GDP mutant
sequester GEFs
Mutant GTPases effect
dominant negative
Expression of Sar1GDP inhibits
COPII formation
COPII cargo
newly synthesised proteins
COPI cargo
retrieved & newly synthesised protein
Clathrin cargo
lysosomal proteins, regulated secretory proteins, endocytosed material
