L4 - Cytoskeleton Flashcards

1
Q

cytoskeleton function

A

1) framework for cell
2) stability
3) shape change (spreading)
4) cell movement

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

3 types of polymers

A

1) actin filaments
2) microtubules
3) intermediate filaments

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

actin filament monomer

A

actin

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

actin filament size

A

smallest

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

microtubules monomer

A

heterodimer made of a + B subunits of tubulin

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

intermediate filaments

A

intermediate filament proteins

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

what is the nuclear lamina beneath the inner nuclear membrane made of?

A

intermediate filaments

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

what are some times of intermediate filament proteins?

A

1) keratin

2) vimentin

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

describe mechanical characteristic of intermediate filaments

A

flexible and rope-like

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

why are intermediate filaments so flexible

A

staggered long subunits

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

similarities between microtubules and actin filaments

A

1) single protofilament is thermally unstable

2) two ends polymerize at different rates

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

minus end speed

A

slow growing

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

plus end speed

A

fast growing

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

how are microtubules assembled?

A

GTP hydrolysis (GTP-tubulin dimers = fast growing, GDP-tubulin dimers = fast disassembly)

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

in microtubules, where does disassembly occur?

A

at plus end

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

how are actin filaments assembled?

A

ATP hydrolysis

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

what is the rate determining step for actin polymerization?

A

nucleation (3 actin monomers forming a trimer)

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

F-actin

A

actin filament

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

G-actin

A

oligomer (3 actin monomers coming together)

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

critical concentration

A

minimum concentration of monomers needed for the net addition

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

where is critical concentration higher?

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

where is critical concentration lower?

A

+ end

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

treadmilling range

A

range where concentration of monomers between CcT and CcD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

nucleation

A

where monomers come together and form an initial stable structure to act as “seed” for polymerization

25
lag phase
time taken for nucleation
26
growth phase
monomers added to exposed ends of growing filament -" elongation
27
eqm phase
growth of polymer balanced with shrinkage
28
dynamic instability
microtubules - phenomenon where microtubules alternate between a period of slow growth and rapid disassembly at one side
29
actin cytoskeleton function
cell spreading/migration
30
ARP2/3 complex function
adds additional nucleation sites and catalyze the formation of a branched actin network to grow near a cell membrane (stays at - end)
31
formin
nucleates new filaments at + end to accelerate polymerization
32
profilin
binds to subunits and brings to growing chain to speed elongation
33
cofilin
binds and destabilizes disassembly
34
capZ
caps actin filament at + end and prevents growth (greatly increases the critical concentration). only can grow at minus end so much slower
35
tropomyosin
stabilizes actin filament
36
stress fibres actin configuration
contractile bundle (by a-actinin)
37
cell cortex actin configuration
gel-like network (by filamin A)
38
filopodium
tight parallel bundles (by fimbrin)
39
phalloidin
Drug that binds F-actin and stabilizes it (can have fluorescent tag)
40
cytochalasin
drug that caps actin filament plus end
41
swinholide
drug that severs actin filaments
42
latrunculin
drug that binds actin subunits and prevent polymerization
43
taxol
drug that binds and stabilizes microtubules
44
colchicine
drug that binds MT subunits and prevents polymerization
45
colcemid
drug that binds MT subunits and prevents polymerization
46
vinblastine
drug that binds MT subunits and prevents polymerization
47
vincristine
drug that binds MT subunits and prevents polymerization
48
nocodazole
drug that binds MT subunits and prevents polymerization
49
Rho GTPase
catalyze important cell shape
50
cell shapes catalyzed by Rho GTPase
1) filopodia (spike-like proj) 2) lamellipodia (sheet-like proj) 3) stress fibers (contractile actin bundles)
51
RhoA activation
stress fibers (contractile actin bundles) -> more integrin + focal adhesion
52
Cdc42 activation
filopodia (spike-like proj)
53
Rac1 activation
lamellipodia (sheet-like proj)
54
Rac-Rho antagonism
Rac promotes protrusion | Rho promotes contract (opposite so need to be coordinated)
55
how is RhoGTPase deactivation regulated?
GEFs
56
how is RhoGTPase activation regulated?
GAPs
57
what protein is needed for cell-matrix adhesion?
integrin, transmembrane receptors (actin and intermediate filaments)
58
how is integrin activated?
receives signal and catalyze conformation chain where it opens up and allows for strong ligand binding
59
focal adhesion
catalyzed by FAK (involve integrin, actin and actin-binding proteins)