lecture 12

Question 1

endocytosis

Answer 1

material goes from outside of cell, cell membrane, to inside of cell

Question 2

exocytosis

Answer 2

secretion; ER to golgi to plasma membrane

Question 3

what is conserved in vesicles

Answer 3

topology; outer leaflet is outer, inner leaflet is inner

Question 4

steps of vesicle biogenesis

Answer 4

coat assembly & cargo selection, bud formation, vesicle formation, uncoating

Question 5

why is coat necessary

Answer 5

vesicle formation hella energetically expensive, need to couple it w/ coats

Question 6

3 coat proteins

Answer 6

clathrin, COPI, COPII

Question 7

clathrin

Answer 7

endocytic vesicles at plasma membrane

Question 8

COPI

Answer 8

on golgi; traffic backwards to ER, grabs proteins that accidentally slipped away (retrograde flow)

Question 9

COPII

Answer 9

creates vesicles at ER to golgi, exocytosis

Question 10

what happens when vesicle is naked

Answer 10

coat proteins fall off, trafficked to where it needs to go

Question 11

2 fates of endocytosed stuff

Answer 11

fuses w/ early endosomes to become late endosomes OR recycled

Question 12

macropinocytosis

Answer 12

non-selective way; receive RTKs, active Rac2, arp2/3, pushes memrbane folds over itself and grabs shi

Question 13

what does macropinocytosis depend on

Answer 13

actin; not coat proteins/cargo receptors; non-selective

Question 14

what are two types

Answer 14

macropinocytosis (less selective), clathrin-mediated endocytosis (more selective)

Question 15

what do Rab proteins do

Answer 15

bind to outside of vesicels, help them fuse w/ correct target membranes

Question 16

how does right cargo get to right place in COPII vesicles

Answer 16

anything secreted out of ER has exit signal, binds to cargo receptors

Question 17

KDEL sequence

Answer 17

4 AA sequence, tells us that protein should stay in ER

Question 18

where are KDEL receptors

Answer 18

cargo receptrs, in golgi

Question 19

what recruits COPI coat

Answer 19

KDEL receptors binding cargo/ER proteins

Question 20

two transport mechanisms

Answer 20

vesicle transport mechanism (Small stuff), cisternal maturation mechanism (huge stuff)

Question 21

constitutive pathway

Answer 21

always on

Question 22

signal mediated

Answer 22

vesicles are made and pre-positioned, don’t fuse until signal received