Protein/Endo Trafficking

Question 1

Three domains of the endoplasmic reticulum

Answer 1

1) Smooth ER
2) Rough ER
3) ERGIC

Question 2

What is the characteristic function of the smooth ER?

Answer 2

lipid metabolism

Question 3

What is the characteristic aspect of the rough ER?

Answer 3

covered by ribosomes

Question 4

What does ERGIC stand for?

Answer 4

ER-Golgi Intermediate Complex

Question 5

How is the golgi apparatus’ structure characterized?

Answer 5

stacked and polarized cisternae

Question 6

Where does the cis face of the golgi apparatus face?

Answer 6

Endoplasmic reticulum

Question 7

What does topology of the secretory pathway refer to?

Answer 7

Shit that is facing the cytosol continues to do so throughout the various fusions, etc.

Question 8

Protein synthesis by free cytosolic ribosomes leads to what type of translocation?

Answer 8

Post-Translational Translocation

Question 9

Protein synthesis by membrane-bound ribosomes leads to what type of translocation?

Answer 9

Co-Translational Translocation

Question 10

Transmembrane proteins must use which method of translocation?

Answer 10

Co-translational translocation

Question 11

What binds the signal sequence translated first in the beginning of co-translational translocation?

Answer 11

Signal Recognition Particle (SRP). Brings it into the SRP receptor on the ER membrane.

Question 12

What does the ribosome bind to on the ER membrane in co-translational translocation?

Answer 12

Translocon

Question 13

Which enzyme cleaves the signal sequence of the growing polypeptide in co-translational translocation?

Answer 13

Signal peptidase

Question 14

What are the heat shock proteins involved in post-translational translocation?

Answer 14

Hsp 70 and Hsp 40. They maintain the protein in an unfolded state.

Question 15

What recognizes the signal sequence in post-translational translocation

Answer 15

Sec62/63

Question 16

What is the name of the ER chaperone which holds proteins unfolded until the whole thing passes through in post-translational translocation

Answer 16

BiP

Question 17

An oligosaccharide synthesized on a lipid carrier. Prevents protein aggregation in the ER, which helps sort signals.

Answer 17

N-linked glycosylation

Question 18

Which terminus are glycolipids added on to create a GPI anchor and attach proteins to the membrane?

Answer 18

C-terminus

Question 19

What is the cytosol-side peptide signal for transmembrane proteins?

Answer 19

2 methionine

Question 20

What is the cytosol-side peptide signal for lumenal proteins?

Answer 20

2 glutamic acid

Question 21

What is the cytosol-side peptide signal for GPI-anchored protein?

Answer 21

2 aspartic acid

Question 22

Specialized region of the ER where proteins and phospholipids are exported in vesicles

Answer 22

ER Exit Site (ERES)

Question 23

What makes up the signals that direct proteins packaged for vesicle transport?

Answer 23

peptide and carbohydrate signals

Question 24

Unmarked proteins in the ER can also be packaged and transported where by a “default pathway”?

Answer 24

Golgi

Question 25

Proteins destined for retrieval by the endoplasmic reticulum have which two targeting sequences at their C termini?

Answer 25

KDEL or KKXX (there's then a KDEL receptor)

Question 26

What two important membrane components are synthesized mostly in the golgi apparatus?

Answer 26

Glycolipids and sphingomyelin

Question 27

Four regions of the Golgi apparatus

Answer 27

1) cis compartment 2-3) medial and trans compartments 4) trans golgi network

Question 28

Region of the golgi apparatus which receives molecules from the ERGIC

Answer 28

cis compartment

Question 29

Region of the golgi apparatus which is responsible for most modifications

Answer 29

medial and trans compartments

Question 30

Region of the golgi apparatus which is the sorting and distribution center

Answer 30

trans-golgi network

Question 31

Golgi protein movement theory in which transport vesicles carry proteins between cisternae

Answer 31

stable cistarnae model

Question 32

Golgi protein movement theory in which proteins are carried within the cisternae, which gradually mature and progressively move through the golgi in the cis to trans direction

Answer 32

cisternal maturation model

Question 33

Which carbohydrates, added to proteins in the ER, are modified in the golgi?

Answer 33

N-linked oligosaccharides

Question 34

In the golgi apparatus, what can mannoses be swapped out for?

Answer 34

1) NAG 2) galactose 3) sialic acids

Question 35

What sugar can be added to the origin N-acetylglucosamine in the Golgi apparatus?

Answer 35

Fucose

Question 36

What phosphorylated sugar signals for proteins to go to the lysosome in the trans golgi network?

Answer 36

mannose-6-phosphate

Question 37

Carbohydrates added to the side chains of serine and threonine, creating proteoglycans, are called....

Answer 37

O-linked glycosylation

Question 38

Three routes to go from the Golgi to the cell surface

Answer 38

1) direct transport to the plasma membrane 2) recycling endosomes 3) regulated secretory pathways

Question 39

What sort of vesicle are hormones and neurotransmitters packaged in the trans-Golgi for regulated release

Answer 39

secretory granules

Question 40

The three types of vesicle coat proteins

Answer 40

1) COPII-coated vesicles 2) COPI-coated vesicles 3) Clathrin-coated vesicles

Question 41

Which family of vesicle coat proteins carries proteins from the ER to the ERGIC and on to the golgi apparatus?

Answer 41

COPII-coated vesicles

Question 42

Which family of vesicle coat proteins bud from the ERGIC or Golgi and carry their cargo back, returning proteins to earlier compartments

Answer 42

COP1-coated vesicles

Question 43

Which family of vesicle coat proteins transport in both directions between the trans Golgi network, endosomes, lysosomes, and the plasma membrane

Answer 43

Clathrin-coated vesicles

Question 44

mnemonic: "two steps forward, one step back"

Answer 44

``` COPII = anterograde transport COPI = retrograde transport ```

Question 45

Which small GTP-bind proteins, related to Ras and Ran, regulate the formation of coated vesicles

Answer 45

ARF1 and Sar1

Question 46

What two things mediate interactions between transport vesicles and target membranes?

Answer 46

tethering factors and Rab proteins (small-GTP binding proteins)

Question 47

What protein on the vesicle drives fusion?

Answer 47

vSNARES

Question 48

What protein on the target membrane drives fusion?

Answer 48

tSNARES

Question 49

What is the motor protein involved in membrane fusion?

Answer 49

Dynamin

Question 50

What does Rab bind on target membranes?

Answer 50

Tethering factors

Question 51

What binding motif do SNARE proteins have?

Answer 51

central coiled-coil domain

Question 52

What is the ideal pH for most of the lysosomal enzymes which are called "acid hydrolases"

Answer 52

5

Question 53

How is a lysosome formed?

Answer 53

A transport vesicle fuses with a late endosome

Question 54

They fuse with endocytic vesicles from the plasma membrane in order to separate molecule for recycling from molecules destined for degradation in lysosomes.

Answer 54

Early endosome

Question 55

Molecules to be recycled are passed to these and back to the plasma membrane

Answer 55

Recycling endosomes

Question 56

Carry molecules to be degraded by lysosomes

Answer 56

Late endosomes

Question 57

Phagosomes fuse with lysosomes to become...

Answer 57

phagolysosomes

Question 58

Mechanism for selective uptake of specific macromolecules

Answer 58

Clathrin-mediated endocytosis

Question 59

Specialized region where macromolecules can bind to cell surface receptors

Answer 59

clathrin-coated pits

Question 60

Endocytosed (is that a fucking word) clathrin-coated vesicles then fuse with what?

Answer 60

early endosomes

Question 61

What causes receptors and ligands to separate in early endosomes?

Answer 61

acidic pH (6.0 - 6.2)

Question 62

Examples of clathrin-independent endocytosis (3)

Answer 62

1) macropinocytosis 2) internalization of caeolae 3) uptake of GPI-anchored plasma membrane proteins clustered in lipid rafts

Question 63

What does LDL stand for

Answer 63

Low-density lipoprotein

Question 64

LDL / clathrin coated pit dysfunction where either the receptors don't bind LDL or the mutations prevent the receptors from concentrating in the coated pits

Answer 64

Familial hypercholesterolemia

Question 65

The six amino acid signal, including tyrosine, which prevents LDL receptors from concentrating in coated is called what

Answer 65

internalization signal

Question 66

What does CEDNIK syndrome stand for?

Answer 66

Cerebral dysgenesis, neuropathy, ichthyosis, and palmoplantar keratoderma

Question 67

What is the inheritance pattern of CEDNIK syndrome?

Answer 67

autosomal recessive

Question 68

What is mutated in CEDNIK syndrome?

Answer 68

SNAP29 (part of the SNARE complex)

Question 69

I-Cell Disease is also referred to as...

Answer 69

mucolipidosis II

Question 70

Which gene is mutated in I-cell disease?

Answer 70

GNPTAB (chromosome 12)

Question 71

GNPTAB gene (well the protein it codes) is the first step in what process?

Answer 71

tagging lysosomal enzymes with mannose-6-phoasphate in the golgi apparatus

Question 72

Coarse facial features, joint limitations, skeletal abnormalities, cardiomegaly, developmental delay, and early loss of life...

Answer 72

I-cell disease