Brainscape's Knowledge GenomeTM

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


See full index

z:Cell 300 > Lecture 19: Cytoskeleton > Flashcards

Lecture 19: Cytoskeleton Flashcards

1
Q

Types of Cytoskeletal Elements from smallest to largest

A

-actin filaments (smallest)
-intermediate filaments
-microtubules (largest)

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

actin filaments (descr.)

A

8-9 nm diameters; twisted tow-stranded structure

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

intermediate filaments (descr.)

A

10 nm rope

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

microtubules (descr.)

A

hollow, tube-like structures; 24 nm diameter

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

action microfilaments are concentrated ______

A

in cortex beneath PM

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

microtubules are attached to ____

A

MTOC (centrosome)

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

intermediate filaments are structural elements that ______

A

provide overall structure for cells

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

Microtubules are tracks in cells that ____

A

allows for transport of vesicles

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

Actin propel ____

A

some movement within cells

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

Function of cell junctions

A

for cells to communicate with each other

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

Intermediate filaments are found in ______ but not _____

A

nearly all animals
plants and fungi

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

Intermediate filaments (IF) are associated with ____ (4)

A

nucleus
ER
mitochondria
PM

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

Intermediate filaments are abundant in what type of cells?

A

epithelial and neuronal cells

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

Most ubiquitous intermediate filaments are _____, found exclusively in the _____

A

lamins
nucleus

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

IF are important for the ____ and _____ of organelles

A

structure and positioning

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

Vimentin-like IF is in what type of cells?

A

neuronal cells

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

Keratin IF is in what type of cells?

A

epithelial cells

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

structure of IF

A

central coiled-coil a-helical “rod” domain, flanked by non-a-helical N-terminal head and C-terminal tail domains

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

vimentin and desmin are IF that _______ filaments

A

homopolymeric

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

keratins are IF that _______ filaments

A

obligate heteropolymers

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

coiled-coil domains had been described for the first time in ____

A

keratin

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

IF proteins are typically _____ and are substrates of _______

A

phosphorylated
caspases during apoptosis

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

During apoptosis, IF are targeted by ____ because _____ (saying)

A

caspases
if you are collapsing a tent, you need to break all the rods holding it up

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

IF (monomer -> dimer –> tetramer –> filament)

A

monomer: coil has directionality with NH2 and COOH ends
coiled-coil dimer: 2 monomers coiled around each other; has directionality with NH2 and COOH ends
tetramer: staggered two coiled-coil dimers; NH2 end of one dimer interacts with COOH end of other dimer: antiparallel- lost directionality
filament: lateral association of 8 tetramers; no directionality

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Directionality of IF

A

no directionality

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

nuclear lamina is where?

A

just inside the inner nuclear membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

nuclear lamina is what? functions?

A

complex meshwork

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

nuclear lamina functions

A

maintenance of nuclear shape
transcriptional regulation
nuclear pore positioning and function
heterochromatin organization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

the nuclear lamina plays a part in transcriptional regulation by binding to _____ such as ____

A

transcription factors
Rb and SREBP-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Hutchinson-Gilford Progeria is caused mutation ____? in exon ___? effect on translated amino acid sequence? effect on protein structure?

A

C1824 to T1824
exon 11
no effect on a.a; still Gly 608
creates cryptic donor splicing site which removes 50 a.a from Lamin A tail

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Hutchinson-Gilford Progeria effect on nuclear structure? phenotype?

A

altered nucleus
affected people have very short lifespan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Microtubules are ___ than intermediate filaments.

A

stiffer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Microtubules are polymers of ____, arranged in a
________ in diameter

A

globular tubulin subunits
cylindrical tube measuring 25 nm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Microtubules (MT) come in two forms

A

stable and short-lived

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

short-lived MT are involved in the formation of ____

A

the spindle apparatus during mitosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

MT can can oscillate between ______ enabling cells to quickly assemble and disassemble microtubules

A

shortening and growing phases,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

MT are built from _____

A

a- and b-tubulin heterodimers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

_______ serves to nucleate polymerization of MT (de novo formation of MTs) in ____

A

g-tubulin
MTOC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Microtubule polymerization involves the binding of
______

A

GTP-loaded b-tubulin in a complex with GTP-loaded a-tubulin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

After GTP-loaded b-tubulin in a complex with GTP-loaded a-tubulin is added to tubule, _____

A

b-tubulin then undergoes GTP hydrolysis (like when it is in the middle)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

polarity of MTs?

A

there is a polarity of MTs (polus and minus end)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

+ end = elongations ______
- end = elongations ____

A

happens faster
happen slower

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

MT: when tubulin exists as subunits, they tend to be ____ then when they become part of MT, ____

A

in GTP-bound form
hydrolysis happens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

MT grow on ____ which are recognized by _____

A

+ ends
the GTP-loaded B-tubulin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

GTP cap of MT(def.)

A

enrichment of GTP-loaded B-tubulin on + end

46
Q

catastrophe of MT (def.) + leads to ___

A

random loss of GTP cap; destruction of MT + end
rapid shrinkage of MT

47
Q

rescue of MT (def.) + leads to _____

A

regain of GTP cap
rapid growth with GTP-capped end

48
Q

nocodazole is a drug that _____

A

interferes with MT formation; causes MT depolymerization

49
Q

microtubules grow and shrink in a _____manner; has ____

A

GTP-dependent
dynamic instability

50
Q

_____is the most abundant protein in cells. In muscle cells, comprises ______, in non-muscle cells makes up _____.

A

Actin
10% of weight of total protein
1-5% of total protein

51
Q

Actin concentration in cell

A

0.1-0.5 mM

52
Q

Actin exists as a ____ and _____

A

globular monomer called G-actin
filamentous polymer called F-actin

53
Q

each actin molecule can bind to ______ through ____

A

ADP or ATP
a magnesium ion

54
Q

Most common forms of actin

A

ATP-G-actin
ADP-F-actin

55
Q

actin is ___-dependent (as a cofactor)

A

ATP

56
Q

Actin polymerization method

A

1)G-action comes together - nucleation
2) G-actin nucleus elongates and becomes F-actin- elongation
3) Steady state

57
Q

___ is a common loading control for cells in the lab

A

actin

58
Q

Actin polymerization requires nucleus of _____

A

polymerized ATP-G-actin

59
Q

actin fiber aka ____

A

F-actin

60
Q

During elongation, F-actin _____ATP to become ______

A

hydrolyzes
ADP-bound F-actin

61
Q

actin formation phases

A

1) nucleation (lag phase)
2) elongation (growth phase)
3) steady state (equilibrium phase)

62
Q

nucleation (lag phase)

A

G actin subunits form oligomers

63
Q

elongation (growth phase)

A

growing actin filaments

64
Q

steady state (equilibrium phase)

A

actin filaments with subunits coming on and off; still dynamic

65
Q

Critical concentration (def.)

A

concentration where there is no net change in polymer

66
Q

Actin formation + thermodynamics

A

it’s favored to have longer action filaments

67
Q

actin polymerization is ___ through the mechanism called ____

A

directional
treadmilling

68
Q

actin polymerization is demonstrated with _____

A

a capping protein that does not allow incorporation of G-actin monomers at either the + or the - end.

69
Q

actin’s polarity is achieved by the ____

A

lower conc (lower critical concentration) required for incorporation into the + end

70
Q

above the critical concentration

A

elongation (adding G-actin)

71
Q

below the critical concentration

A

removing G-actin

72
Q

actin-interfering drugs are also ___ becuase____

A

anti-cancer drugs because these cells require many cell divisions

73
Q

ARPs are ____

A

actin related proteins

74
Q

ARPs exhibit about ____

A

50% sequence simialrity with action

75
Q

ARP2/3 complex contains how many proteins?

A

7 proteins

76
Q

ARP2/3 complex function

A

ARP2/3 simulates actin growth and results in a branch point

77
Q

ATP hydrolysis of ARP2 leads to ____

A

the debranching of ARP2

78
Q

ATP-hydrolysis deficient mutant of ARP2 (arp2H161A) blocks _____

A

debranching of actin y-branches
blocks endocytosis

79
Q

ARP2/3 is controlled by ___

A

Rho family of GTPases

80
Q

GEF action

A

GDP-bound to GTP-bound
Guanine nucleotide exchange factors

81
Q

GAP action

A

GTP-bound to GDP-bound; gas pedal

GTPase-activating protein

82
Q

GDI action

A

keeps it GDP-bound; brake

Guanosine dissociation inhibitors

83
Q

GDP-bound of Rho

A

inactivated form

84
Q

GTP-bound of Rho

A

activated form; effector;engine

85
Q

T17N mutants of Rho

A

permanently bound to GDP, also called kinase-dead
non-active mutant

86
Q

Q61L mutants of Rho

A

permanently bound to GTP, also called
dominant active (ENGINE ALWAYS ON)
always active mutant

87
Q

stress fiber arrangement of actin

A

contractile bundle

88
Q

cell cortex arrangement of actin

A

branched and unbranched filament network

89
Q

lamellipodium arrangement of actin

A

branched network

90
Q

filopodium arrangement of actin

A

tight parallel bundle

91
Q

Rho family members and different arrangements of actin

A

Cdc42 - filopodia
Rac - lamellipodia
Rho - stress fiber

92
Q

NPF stands for _____

A

nucleation-promoting factors

93
Q

NPF are regulated by _____ that ____

A

signal transduction pathways that coordinate actin polymerization in space and time

94
Q

The activation of class I NPFs are by _____

A

Rho-family GTPases CDC42 and Rac.

95
Q

2 important class I NPFs

A

WASP
WAVE

96
Q

the NPF WASP is activated by ______

A

Cdc42

97
Q

the NPF WAVE is activated by ______

A

Rac

98
Q

The activation of NPFs is downstream of a signaling cascade based on _____

A

Rho and Cdc42/rac family GTPases and lipid second messengers

99
Q

Binding of ___ and _____ to WASP, triggers the activation of ______ and dissociation from its _____

A

PI (4,5)P2 and GTP-loaded Cdc42
ARP2/3 complex
inhibitor WIP

100
Q

Activated Rho (_____) binds to NRFs to induce ____

A

Cdc42 or Rac
interaction with Arp2/3

101
Q

WASP stands for_____

A

Wiskott-Adrich Syndrome Protein

102
Q

WASP pattern , when expressed from a transfected plasmid? This pattern______

A

spotty staining pattern
aligns with actin cables

103
Q

Expression of CDC42-N17 (=T17N) effect of WASP pattern? conclusion?

A

disperses spotty staining pattern
Cdc42 interacts with WASP to form branched actin structure

104
Q

WAVE stands for ____

A

Wiskott-Aldrich Verprolin-Homologous Protein

105
Q

Overexpression of WASP and WAVE cause _____

A

abnormally many branching events, resulting in a “dispersal” of the actin cytoskeleton

106
Q

WAVE location in neurons?

A

close to the neurite growth cone

107
Q

WAVE-/- neurons have ____

A

shorter neurons

108
Q

WAVE -/- mice show ____ affecting _____ and ____

A

mental retardation
spatial learning
memory retention

109
Q

WAVE is co-immunoprecipitated with protein ____ which is implicated in ______

A

WRP
human mental retardation

110
Q

The formation of____ structures are also crucial for cell movement

A

filopodia and lamellipodia

111
Q

Spatial learning and memory retention require actin remodeling because _____

A

it enables neurons to form and retain neurite extensions

z:Cell 300 (17 decks)

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