Cytoskeleton Flashcards
Cytoskeleton Roles (5)
Cellular polarity & shape Directional migration Formation of mitotic/meiotic spindle Chromosome segregation Cytokinesis
Cytoskeleton components:
Intermediate filaments
Actin
Microtubules
Intermediate Filaments location (4)
Surround nucleus
Extend to cell periphery
At cell-cell junctions
At cell-ECM junctions
Intermediate Filaments Structure
2 chained coiled coil that forms an antiparallel tetramer
Examples of Intermediate Filaments(3)
Keratin
Neurofilaments
Nuclear lamins
Intermediate Filaments
Controlled by phosphorylation (dynamic)
Role in signaling and controlling gene regulatory networks
Actin Filaments
Polymers of actin with ATP or ADP bound
Helical
Polar (barbed and pointed end)
Microtubules
Polar
Binds GDP or GTP
Polymers of alpha/beta tubulin arranged in tubules with 13 protofilaments
Microtubule examples (5)
Mitotic spindle Cilia Flagella Basal bodies Centrioles
ATP/GTP cap
At growing end
Due to nucleotide hydrolysis lagging behind polymerization
Phalloidin (natural toxin)
Bind and stabilize actin filaments
Colchicine (natural toxin)
Depolymerize microtubules
Taxol (natural toxin)
Bind and stabilize microtubules
Microtubule growth stabilized by ______ and destabilized by _____ which leads to _________
Stabilize: GTP tubulin cap at + end
Destabilize: GDP tubulin at + end
Leads to: rapid depolymerization
+ tip proteins
Inhibit catastrophes to let microtubules get to cell periphery
Primary cilium
Non-motile sensory organelles
Role in developmental signaling pathways