Lecture 11: Motor proteins

Question 1

how does ATP hydrolysis allow motor proteins to move

Answer 1

Because nucleotide binding and hydrolysis alters motor protein shape

Question 2

what do myosins move along in the cell

Answer 2

actin filaments

Question 3

what do kinesin and dyenin move along in the cell

Answer 3

microtubules

Question 4

what direction do kinesin and dyenin move

Answer 4

Kinesin moves towards microtubule plus ends (so towards edge of cell)
Dynein moves towards microtubule minus ends (towards inner cell)

Question 5

what strcuture is kinesin 1

Answer 5

coiled coil
with a dimer of heavy chains on the end which binds to the cargo

Question 6

what are the 2 types of dyenin

Answer 6

cytoplasmic
axonemal - found in cillia and flagella

Question 7

what is name of dyenin’s partener complex

Answer 7

dynactin

Question 8

if there’s only 1 type of dyenin, then how does it bind so many diff cargos

Answer 8

cuz diff adaptor proteins
which change depedning on cargo

Question 9

what direction is ER movement, and which motor protein does it use

Answer 9

mainly moves outwards using kinesin
some inward movement via dyenin

Question 10

what direction is golgi moemvent and which motor protein does it use

Answer 10

invards
via dyenin

Question 11

how would viruses use motor proteins of a cell

Answer 11

get transported from membrane to nucleus via dyenin
either in an endosome or as the viral capsid

Question 12

how can microtubles act like cargo for motor proteins

Answer 12

some motors cause the microtubules to slide along each other

Question 13

what are the 2 types of sliding the mcirotubules

Answer 13

anti parallel - mitotic/meiotic spindle
parallel - cillia and flagella

Question 14

microtubules in cillia

Answer 14

basically just extra mictotubules in cilia
nucleated by the basal body (basal lamina)

Question 15

axonemal dyenin causes cilia/flagella to ‘beat’ by making the MT slide:
what makes sure the MT dont just slide away from each other

Answer 15

linking protiens

Question 16

what myosin is most used in animals

Answer 16

muscle myosin (myosin II)
but found in many cells not just muscle

Question 17

myosin II structure

Answer 17

coiled coil tail
assemble into bipolar filaments

Question 18

what is desmin

Answer 18

intermidiate filaments that stabilise muscle Z discs
(Z discs hold the actin filaments together)

Question 19

what can mutations in desmin cause

Answer 19

muscular dystrophy
cardiac myopathy

Question 20

how does myosin II generate the enrgy to move across actin

Answer 20

ATP hydrolysis
ATPase cycle cuases conformational changes allowing it to move

Question 21

how is myosin I diff to myosin II

Answer 21

has one head

Question 22

function of mysoin I

Answer 22

short distance organelle movement

Question 23

function of myosin II

Answer 23

mostly msucle contraction
but also present in stress fibres (contractile bundles)

Question 24

what’s the diff in distances that mysoin moves in animals comapred to plants/fungi

Answer 24

animals - short distance
plants/fungi - long distance