BI203 Lecture 17: Protein Sorting and Transport - Slides 65-87 (Vesicle Formation, Sorting and Adaptor Proteins, Trans-Golgi Modifications)

Question 1

Vesicle budding is driven by the assembly of ___ ___ ___.

Answer 1

vesicle coat proteins

Question 2

Vesicle coat protein assembly occurs in ___ steps.

Answer 2

four

Question 3

Vesicle coat protein assembly occurs in four steps:

1) Coat proteins attach to the ___ side of membranes.
2) While attaching they interact with one another to assemble into a ___ ___.
3) The lattice structure distorts the membrane to initiate ___ ___.
4) Continued assembly drives release of a ___ ___.

Answer 3

cytosolic, lattice structure, vesicle budding, coated vesicle

Question 4

ASIDE:

The vesicle coat is disassembled before ___ at the target membrane.

Answer 4

docking

Question 5

___ = The coat protein for vesicles traveling between the ER and Golgi Apparatus.

Answer 5

COP

Question 6

___ = The coat protein for vesicles traveling between the Golgi Apparatus and Plasma Membrane.

Answer 6

Clathrin

Question 7

___-coated vesicles carry proteins from the ER to the ERGIC and on to the Golgi apparatus.

Answer 7

COPII

Question 8

___-coated vesicles bud from the ERGIC or Golgi and carry their cargo back, returning proteins to earlier compartments.

Answer 8

COPI

Question 9

___-coated vesicles transport in both directions between the trans Golgi network, endosomes, lysosomes, and plasma membrane.

Answer 9

clathrin

Question 10

Clathrin is a multi-subunit protein with a ___ structure.

Answer 10

triskelion

Question 11

Cells have ___ (aka, ___) ___ that recruit cargo into budding vesicles.

Answer 11

trafficking, sorting, proteins

Question 12

Trafficking proteins interact with vesicle coat proteins via ___ ___.

Answer 12

adaptor proteins

Question 13

These adaptor proteins bind:

1) ___ tail of cargo.
2) ___ coat proteins.

Answer 13

cytoplasmic, vesicle

Question 14

Formation of coated vesicles is regulated by small ___-binding proteins such as ARF1, related to Ras and Ran.

Answer 14

GTP

Question 15

Formation of coated vesicles is regulated by small GTP-binding proteins such as ___, related to Ras and Ran.

Answer 15

ARF1

Question 16

GTP-binding proteins recruit ___ ___ that mediate vesicle assembly by interacting with cargo proteins and with coat proteins.

Answer 16

adaptor proteins

Question 17

Recall the ___ ___ and adaptor proteins in receptor-mediated endocytosis.

Answer 17

LDL receptor

Question 18

___ key modifications within the Golgi Apparatus.

Answer 18

2

Question 19

Two key modifications within the Golgi Apparatus:

Answer 19

O-linked glycosylation, Modification of N-linked sugars added in the ER

Question 20

___ ___ - Sequential addition of carbohydrates to serine or threonine.

Answer 20

O-linked glycosylation

Question 21

O-linked glycosylation - Sequential addition of carbohydrates to ___ or ___.

Answer 21

serine, threonine

Question 22

Specific processing of ___ ___ in the Golgi targets glycoproteins to their final destination.

Answer 22

N-linked oligosaccharides

Question 23

N-linked oligosaccharides that were added in the ___ are modified by a sequence of reactions catalyzed by enzymes in different compartments in the Golgi.

Answer 23

ER

Question 24

Targeting of proteins to the ___ ___ from the Golgi entails sequential reactions.

Answer 24

plasma membrane

Question 25

Targeting of proteins to the plasma membrane from the Golgi entails ___ reactions.

Answer 25

sequential

Question 26

For example: the LDL receptor, critical for cholesterol metabolism and involved in hypercholesterolemia, is both ___ and ___.

These modifications ultimately give the protein stability and also help direct the LDL receptor to its final destination: the ___ ___.

Answer 26

N-, O-glycosylated, plasma membrane

Question 27

___ ___ proteins are targeted by the attachment of mannose-6-phosphate in the Trans-Golgi Network, which transports them to endosomes and on to lysosomes.

Answer 27

Lysosomal luminal proteins

Question 28

Lysosomal luminal proteins are targeted by the attachment of ___ in the Trans-Golgi Network, which transports them to endosomes and on to lysosomes.

Answer 28

mannose-6-phosphate

Question 29

Lysosomal luminal proteins are targeted by the attachment of mannose-6-phosphate in the ___ ___, which transports them to endosomes and on to lysosomes.

Answer 29

Trans-Golgi Network

Question 30

Lysosomal luminal proteins are targeted by the attachment of mannose-6-phosphate in the Trans-Golgi Network, which transports them to ___ and on to ___.

Answer 30

endosomes, lysosomes

Question 31

Transport of proteins from the Trans-Golgi network to their final destination begins with ___ ___ into distinct transport vesicles.

Answer 31

selective packaging

Question 32

At the Trans-Golgi Network in the newly budding transport vesicle, adaptor proteins bind the cytoplasmic tail of ___ ___.

Answer 32

sorting receptors