Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Molecular biology - Sarah > Endomembranes I: Moving Proteins and Membranes in the Secretory Pathway > Flashcards

Endomembranes I: Moving Proteins and Membranes in the Secretory Pathway Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

Principles of vesicle trafficking

A

1) Cargo selection
2) Vesicle budding from one compartment
3) Transport
4) Fusion with a second compartment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Studies that used ___ established understanding of the molecular mechanisms involved in vesicle trafficking.

A

biochemical, subcellular fractionation, and genetic approaches

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Protein transport through the secretory pathway can be visualized by ____.

A

fluorescence microscopy of cells producing a GFP-membrane fusion protein (fluorescent molecule movement tracked over time)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Transport of a membrane glycoprotein (VSVG) can be assayed by ____.

A

Sensitivity to endoglycosidase D

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Transport of ___ can be assayed by sensitivity to endoglycosidase D.

A

a membrane glycoprotein (VSVG)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Yeast Sec mutant mutation experiment lead to what discovery?

How did it work?

A

Tracking of the secreted protein invertase in S. cerevisiae, and identification of ts mutants with defects at various steps, led to the discovery of numerous players in vesicle trafficking.
Conditional or temperature-sensitive (ts) mutants secrete invertase at permissive, lower temperature but accumulate proteins in the cell at restrictive or high temp.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Yeast sec mutants

Class, defect, and fate of protein

A

Class A:
Fate of proteins (FoP): Accumulation in the cytosol, Defect (D): transport into the ER
Class B:
FoP: Accumulation in rough ER, D: Budding of vesicles from the rough ER
Class C:
FoP: Accumulation in ER-to-Golgi transport vesicles, D: Fusion of transport vesicles with golgi
Class D:
FoP: Accumulation in Golgi, D: Transport from Golgi to secretory vesicles
Class E:
FoP: Accumulation in secretory vesicles, D: Transport from secretory vesicles to cell surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

In normal mammalian cells, VSVG is modified in the Golgi by ____.

A

an GlcNAc transferase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

In normal mammalian cells, ____ is modified in the Golgi by GlcNAc transferase.

A

VSVG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How does a cell-free assay work?

A

Isolated Golgi stacks from uninfected wild-type and infected mutant cell lines are combined in the test tube, then VSVG is glycosylated.
It showed intercompartmental transport.
Assumes that vesicles transport cargo (VSVG) or enzymes between golgi.

From what I understand, when the mutant cell was incubated with the wild type cell, the N-Acetylglucosamine was added to the protein of interest. When the cells were separate, N-acetylglucosamine was not added to the protein of interest.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

The addition of N-acetylglucosamine requires ___.

A

Transport vesicles, cytosol, and ATP and GTP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Mechanical forces used in vesicle transport:

A

Scission, propulsion/motility

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Target recognition protein

A

Rab GTPases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Membrane function protein

A

SNAREs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

____ drives vesicle budding and selection of cargo.

A

Coat assembly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Cargo can be ____ or ___.

A

soluble, luminal proteins or integral membrane proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Vesicle Coat types:
Transport Step Mediated
Coat proteins
Associated GTPase

A

COPII:
ER to cis-Golgi; Sec23/Sec24 and Sec13/Sec31 complexes, Sec16; Ser1
COPI:
cis-Golgi to ER, later to earlier Golgi cisternae; Coatamers containing seven different COP subunits; ARF
Clathrin and adapter proteins:
trans-Golgi to endosome; Clathrin and AP1 complexes or Clathrin and GGA; ARF
Plasma membrane to endosome; Clathrin and AP2 complexes; ARF
Golgi to lysosome, melanosome, or platelet vesicles; AP3 Complexes; ARF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

COPII:
Transport Step Mediated
Coat proteins
Associated GTPase

A

ER to cis-Golgi;
Coat Proteins: Sec23/Sec24 and Sec13/Sec31 complexes, Sec16;
Associated GTPase: Ser1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

COPI:
Transport Step Mediated
Coat proteins
Associated GTPase

A

cis-Golgi to ER, later to earlier Golgi cisternae;
Coat proteins: Coatamers containing seven different COP subunits;
Associated GTPase: ARF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Clathrin and adapter proteins:
Transport Step Mediated
Coat proteins
Associated GTPase

A

trans-Golgi to endosome; Clathrin and AP1 complexes or Clathrin and GGA; ARF

Plasma membrane to endosome; Clathrin and AP2 complexes; ARF

Golgi to lysosome, melanosome, or platelet vesicles; AP3 Complexes; ARF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

SAR1 and ARF are members of ____.

A

the Ras GTPase superfamily

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What proteins affect GTPase?

A

GEF activates GTPases, GAP deactivates GTPases

23
Q

Cytoplasmic Sar1 is activated and recruited to ER membrane by ____.

A

Sec12, an integral membrane protein

24
Q

Sec12 is a ___ for ___; catalyzes the exchange of ___ for ___.

A

GEF for Sar1

GDP for GTP

25
Q

GTP-Sar1 undergoes a conformational change, exposing the ____ for membrane association. ARF has an ___.

A

hydrophobic N-terminus,

N-terminal myristate group

26
Q

GTP-Sar1 recruits _____ to the membrane.

A

the heterodimeric Sec23/Sec24 coat (COPII) proteins

27
Q

___ recruits cargo to the vesicle budding site

A

Sec24

28
Q

____ joins the coat and self-polymerizes into lattices

A

Sec13 and Sec31 heterodimer

29
Q

Sec23 is a ___ for ___; stimulates ____ after coat assembly

A

GAP for Sar1,

GTP hydrolysis

30
Q

COPI
Signal Sequence
Proteins with Signal
Signal Receptor

A

Lys-Asp-Glu-Leu (KDEL); ER-resident soluble proteins; KDEL receptor in cis-golgi membrane

Lys-Lys-X-X; ER-resident soluble proteins; COPI alpha and beta subunits

31
Q

COPII
Signal Sequence
Proteins with Signal
Signal Receptor

A

Di-acidic (e.g. Asp-X-Glu); Cargo membrane proteins in ER; COPII Sec24 subunit

32
Q

Clathrin/AP1
Signal Sequence
Proteins with Signal
Signal Receptor

A

Mannose-6-phosphate; soluble lysosomal enzymes after processing in cis-Golgi; M6P receptor in trans-golgi membrane

Tyr-X-X-Sai; Membrane proteins in trans-Golgi; AP1 (mew1 subunit)

33
Q

Clathrin/AP2
Signal Sequence
Proteins with Signal
Signal Receptor

A

Mannose-6-phosphate; secreted lysosomal enzymes; M6P receptor in plasma membrane

Asn-Pro-X-Tyr (NPXY); LDL receptor in plasma membrane; AP2 complex

Tyr-X-X-Sai; Plasma membrane proteins; AP2 (mew2 subunit)

Leu-Leu; Plasma membrane proteins; AP2 complexes

34
Q

Mannose-6-Phosphate
Proteins with signal
Signal Receptor
Vesicles that incorporate Signal-bearing protein

A

soluble lysosomal enzymes after processing in cis-Golgi; M6P receptor in trans-golgi membrane; Clathrin/AP1

secreted lysosomal enzymes; M6P receptor in plasma membrane; Clathrin/AP2

35
Q

Lys-Asp-Glu-Leu
Proteins with signal
Signal Receptor
Vesicles that incorporate Signal-bearing protein

A

ER-resident soluble proteins; KDEL receptor in cis-golgi membrane; COPI

36
Q

Di-acidic (e.g. Asp-X-Glu)
Proteins with signal
Signal Receptor
Vesicles that incorporate Signal-bearing protein

A

Cargo membrane proteins in ER; COPII Sec24 subunit; COPII

37
Q

Cystic Fibrosis

A

CFTR, encodes an integral membrane protein that is normally transported to the PM through the secretory pathway in epithelial cells

CFTR is a chloride channel that has di-acidic sorting signal for packaging in COPII vesicles at the ER.

A common mutation, ΔF508, blocks export of CFTR from the ER, perhaps by changing the conformation or exposure of the di-acidic sorting signal so that it can no longer bind to Sec24.

38
Q

Like Sar/Arf, GTP-Rab undergoes a conformational change to expose an ___ that associates with membranes

A

prenylated anchor

39
Q

Steps of fusion of transport vesicle with cell membrane

A

Step 1 : A Rab protein tethered via a lipid anchor to a secretory vesicle binds to an effector protein complex on the plasma membrane, thereby docking the transport vesicle on the appropriate target membrane. Step 2 : A v-SNARE protein (in this case, VAMP} interacts with the cytosolic domains of the cognate t-SNAREs (in this case, syntaxin and SNAP-25}. The very stable (oiled-coil SNARE complexes that are formed hold the vesicle close to the target membrane. Step 3: Fusion of the two membranes immediately follows formation of SNARE complexes, but precisely how this occurs is not known.
Step 4: Following membrane fusion, NSF in conjunction with alpha-SNAP protein binds to the SNARE complexes. The NSF-catalyzed hydrolysis of ATP then drives dissociation of the SNARE complexes, freeing the SNARE proteins for another round of vesicle fusion. Also at this time, Rab-GTP is hydrolyzed to Rab-GDP and dissociates from the Rab effector (not shown}.

40
Q

Functions of the golgi apparatus

A

Transport and Packaging

Modification and Synthesis of oligosaccharides

41
Q

The ___ face of the golgi is the forming face and the ___ face is the maturing face.

A

cis,

trans

42
Q 
Lys-Lys-X-X
Proteins with signal
Signal Receptor
Vesicles that incorporate Signal-bearing protein
Where contents go
A

ER-resident soluble proteins; COPI alpha and beta subunits; COPI; Golgi to ER

43
Q

______ of luminal proteins, like BiP or PDI, is necessary & sufficient to allow ER localization.

A

KDEL or HDEL at the C-terminus

44
Q

Mis-sorted ____ are recovered from cis-Golgi by a ___ receptor that interacts with COPI coats–retrograde transport.

A

KDEL proteins,

KDEL

45
Q

Cisternal maturation model of maturation/trafficking through the Golgi apparatus

A

Cisterna form on one side, mature and move through the stack.
Cargo stay with its cisterna (no forward vesicle trafficking)
Enzymes move backward by retrograde flow (COPI vesicles)

46
Q

Which is the correct model of maturation/trafficking through the Golgi apparatus?

A 
Cisternal maturation (not Vesicle Shuttling)
Evidence is Algal scales and collagen fibrils
47
Q

Clathrin is associated with protein transport to ___.

A

Late endosomes

48
Q

AP3 is associated with protein transport to ___.

A

lysosomes

49
Q

Enzyme activities required to modify one or more mannose residues on C-6, generating M6P

A

GlcNAc phosphotransferase, has a binding site for lysosomal protein recognition. A phosphodiesterase trims off GlcNAc.

50
Q 
Tyr-X-X-Sai
Proteins with signal
Signal Receptor
Vesicles that incorporate Signal-bearing protein
Where contents go
A

Membrane proteins in trans-Golgi; AP1 (mew1 subunit); Clathrin/AP1; Contents moved to late endosome

Plasma membrane proteins; AP2 (mew2 subunit); Clathrin/AP2; Contents moved to late endosome

51
Q

M6P Receptor unloads/ releases its cargo under what condition?

A

At acidic pH

52
Q

Lysosomal storage diseases

A

Tay Sachs, Mucopolysaccharide Storage and I-cell disease
Caused by absence of one or more lysosomal enzymes. Thus, undigested glycolipids and extracellular components accumulate in lysosomes as large inclusions.

53
Q

I-Cell Disease

A

Caused by loss of multiple enzymes. Patients lack N-acetylgluosamine phosphotransferase required for formation of M6P on lysosomal enzymes in the cis-Golgi. This leads to secretion of the lysosomal enzymes and lack of proper lysosomal action. Patients suffer from abnormalities of face/skull; growth delays; mental retardation. Study of I-cell disease patients was valuable in determining the fact that M6P targeted enzymes to the lysosome and that such enzymes were sometimes secreted and then taken up and incorporated into lysosomes.

Molecular biology - Sarah (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions