Important terms for Quest 4 (microtubules + motors)

Question 1

What is diameter of microtubules?

Answer 1

25 nm

Question 2

How can you describe the makeup of microtubules?

Answer 2

hollow tubes assembled from alpha-beta tubular dimers

Question 3

What is the order of the assembly in vitro?

Answer 3

lag phase, elongation phase, plateau phase

Question 4

What is the lag phase?

Answer 4

Before the tube is formed, assembly less energetically favorable so slower

Question 5

What is a GTP cap?

Answer 5

puts a stop to GTP dimers, prevents microtubule from peeling apart (allow it to be more stable)

Question 6

What is an MTOC?

Answer 6

Microtubule Organizing Center. Microtubules assemble from these. Centrosome is a kind of this.

Question 7

What is a gamma tubular ring?

Answer 7

circle of game tubular subunits; where the microtubule comes out from centrosome (plus side coming out)

Question 8

What is dynamic instability?

Answer 8

Microtubule can be broken down and recycled, used in a different place; allows movement, what makes microtubules important; establish specific tracks to specific places

Question 9

What protein promotes assembly?

Answer 9

EB1 (End Binding protein 1)

Question 10

What do Tip1, Tea2, and Mal3 do?

Answer 10

transport cargo to the actin cortex

Question 11

What do MCAK, EB1, TIP150 do?

Answer 11

maintain inter-kinetochore tension. Transmits cortical forces for spindle positioning

Question 12

What do Bim1, Kar9, and Bik1 do?

Answer 12

tracks depolymerizing microtubules. Transmits cortical forces for spindle positioning and proper mother-bud segregation.

Question 13

What do biomolecular condensates do in relate to microtubules

Answer 13

Recruit proteins to the ends of microtubules

Question 14

What is tread milling?

Answer 14

loss of subunits at negative end of microtubule offset by assembly at plus end (moving self along, stays same length, movement depends on disassembly and assembly)

Question 15

How are microtubules stabilized?

Answer 15

Microtubule capping proteins

Question 16

What is a MAP and its function?

Answer 16

Microtubule associated protein. Regulate stability, dynamics, and organization of microtubules

Question 17

What does XMAP215 do?

Answer 17

Helps recruit new dimers to gamma tubular ring complex

Question 18

What is the MAP that destabilizes microtubules by binding to multiple dimers?

Answer 18

Stathmin

Question 19

What is MAP that stabilizes microtubules by binding to multiple dimers?

Answer 19

Tau

Question 20

What is the function of katanin and spastin?

Answer 20

microtubule severing MAPs

Question 21

What do post-translational modifications do for microtubules?

Answer 21

diversify structures, change MAP binding

Question 22

What is taxol?

Answer 22

drug that binds + stabilizes microtubules

Question 23

What are colchicine, colcemid, vinblastine, vincristine?

Answer 23

drugs that bind dimers and prevent polymerization

Question 24

What is epothilone B?

Answer 24

naturally occurring microtubule stabilizer (promotes axonal recovery after injury)

Question 25

How is Golgi related to microtubules?

Answer 25

transport (vesicles)

Question 26

How do microtubule motors move?

Answer 26

"walk" along microtubule, powered by ATP, binding + releasing --> mechanical movement, can walk forwards or backwards

Question 27

What is dynein?

Answer 27

motor protein, minus (-) end directed, retrograde (backward transport to cell body)

Question 28

What is kinesin?

Answer 28

motor protein, plus (+) end directed, anterograde (outward transport to axon terminal)

Question 29

How do the motor proteins move in a certain way?

Answer 29

bind in a certain way so it can walk that way

Question 30

How can kinesin's walking step power be described?

Answer 30

modular, symmetric

Question 31

How can dynein's walking step power be described?

Answer 31

irregular

Question 32

What are the function(s) of kinesin?

Answer 32

mostly transport

Question 33

What are the function(s) of dynein?

Answer 33

ciliary beating and intraflagellar transport, interphase cargo transport, mitotic spindle assembly and function

Question 34

How does the the cilia move?

Answer 34

power stroke from microtubule sliding

Question 35

What creates cilia?

Answer 35

Basal bodies

Question 36

What does 9+2 geometry refer to?

Answer 36

Structure of motile cilia, 9 outer doublets and 2 singlets

Question 37

What drives bend formation of flagella?

Answer 37

Dynein movement, microtubule sliding, one side motor engaged, other side inhibited

Question 38

What does 9+0 geometry refer to?

Answer 38

Structure of immotile (primary) cilia, 9 outer doublets and 0 singlets

Question 39

What is the difference between motile and immotile cilia?

Answer 39

Immotile (primary) cilia = sites of signal reception; motile cilia = facilitate flow of fluids