4. Motor proteins & intermediate filaments Flashcards
name the 2 key microtubule motor proteins
kinesin and dynein
what is anterograde transport, which motor protein does this
cargo moves towards + end of the microtubule
kinesin
what is retrograde transport, which motor protein does this
cargo moves towards - end of the microtubule
dynein
describe the structure of kinesin
- head domain has ATP binding site + microtubule binding site
- neck region is flexible and responsible for the direction of movement
- motor domain generates movement
what is the structure of kinesin 1
has 2 heads which bind to microtubule sites and step forwards along the microtubles
what is the speed of kinesin
600 nm
where is kinesin 5 found
in mitotic spindle
what is the role of kinesin 13
assists in disassembly of microtubules at + end and - end
how are dyneins linked to their cargo
linked by large complexes of dynactin
what is a similarity between dynein and kinesin
both has ATPase domains and microtubule binding domains
what does cilia and flagella movement depend on
Bending of the axoneme generated by motor proteins
why does the axoneme bend rather than slide past
due to restrictions imposed by cross-linking protein nexin in the axoneme.
what are the 3 types of microtubules in spindle fibers
kinetochore microtubules, polar microtubules, astral microtubules
what do kinetochore microtubules do
connect chromosomes to the spindle poles
what do polar microtubles do
overlap and are involved in holding the poles together and regulating pole-pole distance
what do astral microtubules do
help position the spindle and determine the plane of cytokinesis
what proteins form intermediate filaments
keratin or lamin
what is the role of intermediate filaments
provide mechanical support for the nuclear membrane or for cell adhesion
what class of intermediate filaments are involved in tissue strength
class 1 and 2
what class of intermediate fibre is involved in axon organisation
class 4
what is the structure of intemediate filaments
alpha helical rod structure, that overlap producing a rope-like structure
assembled into an antiparallel tetramer
what is the intermediate fibre tetramer assembled into
assembled into protofilaments, twisted into a robe like structure called a protofibril
what is the role of intemediate filament associated proteins (IFAP)
connect adjacent IFs together, interact with skeletal components
give an example of IFAPs
plakins
