Cytoplasmic Dynein Mechanism Flashcards

1
Q

Which direction does dynein move?

A

Towards minus end

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

What does dynein move along?

A

Microtubules

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

What is the function of dynein?

A
  • Involved in transporting cellular cargo
  • Providing forces and displacements important in mitosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the general strutcture of dynein?

A
  • Heavy chain heterdimer with multiple light chains
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What binds cargo in dynein?

A

~160 kDa N-terminal domain which binds multiple light chains

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

In dynein what does dimerisation require?

A

Multiple diverse accessory subunits

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

How big is the motor domain of dynein?

A

~380 kDa

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

What is the structure of the motor in each heavy chain of dynein?

A

Contains 6AAA+ ATPase units which fold into a ring structure

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

What does the linker structure of dynein do during powerstroke?

A

Moves across the AAA+ ring

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

What extends from the AAA+ ring of dynein?

A

A coiled coil and microtubule binding site

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

What is the structure of an AAA+ module?

A
  • Contains a large and small subunit domain
  • Small subdomains pack against large domains of next module
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

how many ATPase sites are there on the AAA+ motor of dynein?

A

2

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

Which AAA modules of dynein possess walker A domain motifs?

A

AAA 1-4

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

What is the principal ATPase site in AAA+ motors of dynein?

A

AAA1

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

What is the function of AAA3 module of dynein motor?

A

Regulates communication between linker and AAA1

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

How does dynein communication changes driven by ATP hydrolysis into the microtubule binding domain?

A
  • Via the stalk, 2 alpha helices of coiled coil slide past each other
  • changes in the ring are communicated as pulling and pushing of coiled coil alpha helices changes conform of MTBD
17
Q

Is dynein as processive as kinesin?

A

No

18
Q

What does the axial path of dynein show?

A

It is variable and indicates that dynein can step between protofilaments

19
Q

What mechanism does dynein use to move?

A

Both inchworm and hand-over-hand

20
Q

What is the average step size for dynein?

A

16nm

21
Q

How far does the cargo move on average in dynein per step?

A

8nm

22
Q

Why is it useful for dynein to be able to step between protofilaments?

A

Kinesin moves the opposite direction so allows for the ability to switch paths and avoid kinesin

23
Q

How can adaptor proteins alter dynein motor activity?

A

by binding to cargo or altering the number of dyneins present

24
Q

Give 2 examples of dynein adaptor proteins

A
  • Dynactin
  • BICD2
25
Q

What happened to motor activity of dynein when dynactin and BICD2 were added?

A

It became more processive

26
Q

Why might adding dynactin and BICD2 to dynein make it more processive?

A
  • May be due to altering of motor activity
  • Scaffolds for binding multiple dyneins
27
Q

What experiment can be done to determine if single or multiple dyneins are being used?

A
  • Make dyneins labelled with either pink or green chemicals
  • When both labels are present it appears white
  • Use single molecules fluoscence microscopy
  • Stack images to track where things are bound
28
Q

Were the majority of processive events for dynein monomers or multimers?

A

Monomers