Lecture 18 Cytoskeleton: IFs, Actin, Mysosin Flashcards
what is the cytoskeleton involve
cell shape, mobility, structure, intracellular movement
what are monomer/filaments
individual proteins that can form into much longer/larger filaments
what is polymerization
putting monomers together
What is the energy source for polymerization
Like most things, ATP (actin) or GTP (microtubules)
What are lamins?
They surround and protect the nucleus
What are keratins?
holds together skin, hair, nails
What happens if a keratin is defective
it forms a blister in the basal layer
What are lamins and keratins classified as?
intermediate filaments
What are Actin filaments responsible for
cell movements, shape, and some intracellular movements, endocytosis
What are 2 protofilaments
A filament made of strings of single monomers
What is polarity mean within a actin filament
end of the filaments are different; barbed vs pointed
What do actin cross linknig proteins do?
bring many filaments together into bundle structure
What is Myosin?
causes movement along the actin filaments
What are motor proteins
they use ATP to generate motion
What is a heavy chain (on myosin)
one molecule with three domains
What does the head of a heavy chain do
uses ATP to bind actin
What does the neck on a heavy chain do
flexible region; part that is regulated
What does the tail of a heavy chain do
binds cargo
What are light chains?
regulatory proteins; bind neck; necessary to turn on the heavy chains to function
What drives the light chain
calcium
What does myosin being a dimer mean?
One head is always bound to actin
What does it mean when actin filaments are fixed?
They can slide
What is cell motility (movement) driven by?
polymerization of actin cytoskeleton
