Lecture 11: Motor proteins Flashcards
how does ATP hydrolysis allow motor proteins to move
Because nucleotide binding and hydrolysis alters motor protein shape
what do myosins move along in the cell
actin filaments
what do kinesin and dyenin move along in the cell
microtubules
what direction do kinesin and dyenin move
Kinesin moves towards microtubule plus ends (so towards edge of cell)
Dynein moves towards microtubule minus ends (towards inner cell)
what strcuture is kinesin 1
coiled coil
with a dimer of heavy chains on the end which binds to the cargo
what are the 2 types of dyenin
cytoplasmic
axonemal - found in cillia and flagella
what is name of dyenin’s partener complex
dynactin
if there’s only 1 type of dyenin, then how does it bind so many diff cargos
cuz diff adaptor proteins
which change depedning on cargo
what direction is ER movement, and which motor protein does it use
mainly moves outwards using kinesin
some inward movement via dyenin
what direction is golgi moemvent and which motor protein does it use
invards
via dyenin
how would viruses use motor proteins of a cell
get transported from membrane to nucleus via dyenin
either in an endosome or as the viral capsid
how can microtubles act like cargo for motor proteins
some motors cause the microtubules to slide along each other
what are the 2 types of sliding the mcirotubules
anti parallel - mitotic/meiotic spindle
parallel - cillia and flagella
microtubules in cillia
basically just extra mictotubules in cilia
nucleated by the basal body (basal lamina)
axonemal dyenin causes cilia/flagella to ‘beat’ by making the MT slide:
what makes sure the MT dont just slide away from each other
linking protiens
what myosin is most used in animals
muscle myosin (myosin II)
but found in many cells not just muscle
myosin II structure
coiled coil tail
assemble into bipolar filaments
what is desmin
intermidiate filaments that stabilise muscle Z discs
(Z discs hold the actin filaments together)
what can mutations in desmin cause
muscular dystrophy
cardiac myopathy
how does myosin II generate the enrgy to move across actin
ATP hydrolysis
ATPase cycle cuases conformational changes allowing it to move
how is myosin I diff to myosin II
has one head
function of mysoin I
short distance organelle movement
function of myosin II
mostly msucle contraction
but also present in stress fibres (contractile bundles)
what’s the diff in distances that mysoin moves in animals comapred to plants/fungi
animals - short distance
plants/fungi - long distance
