Exam 2 - Cytoskeleton Flashcards
What property of the cytoskeletal polymers allows for rapid assembly and disassembly?
Held together by weak noncovalent interactions
What cytoskeletal polymer catalyzes the hydrolysis of ATP?
Actin
What cytoskeletal polymer catalyzes the hydrolysis of GTP?
Microtubules
What cytoskeletal polymer does not catalyze the hydrolysis of a nucleotides?
Intermediate filaments
What cytoskeletal polymers are asymmetrical?
Actin and microtubules
What cytoskeletal polymer is symmetrical?
Intermediate filaments
General term for cytoskeletal filaments. Long linear strings of protein subunits that join end-to-end.
Protofilaments
Accessory proteins. Bind to polarized cytoskeletal filaments, use energy from ATP hydrolysis to move along the filament the are associated with.
Motor proteins
Initial aggregate of 3 actin monomers. Start of polymerization.
Nucleation
The change from growth to rapid shrinkage of a microtubule. Loss of GTP cap at plus end.
Catastrophe
The change from rapid shrinkage to growth of microtubule. Regain GTP cap at plus end.
Rescue
Phenomenon where the rate at which the subunits at the minus end are being removed is equal to the rate at which the subunits are being added at the plus end therefore maintaining an actin polymer with a constant length.
Treadmilling
What is the rate-limiting step in the formaiton of cytoskeletal filament?
Nucleation
Nucleoside hydrolysis by actin and tubulin are respnsible for what phenomena?
Treadmilling and dynamic instability
True/False: Actin monomers are microtubule subunits.
False, tubulin