Topic 13 Flashcards
3 types of protein filaments
actin, intermediate and microtubules
predominant cytoskeletal protein of cells
actin
filamentous actin
thin, flexible and consists of head to tail arrangement of g actin polymerized into filaments (helical structure)
actin polymerization is…
reversible
actin filaments are also known as…
microfilaments
globular actin
actin monomer that has tight binding sites
pointed (-) end of actin filament
slow monomer addition
barbed (+) end of actin filament
rapid monomer addition
ATP actin
associates with filaments more readily
ADP actin
dissociates from filaments more readily
treadmilling
equilibrium between rate of addition and removal of monomers; occurs in vitro
actin
stabilization, polymerization, depolymerization are all regulated by….
several actin binding proteins
formin
catalyze initiation of actin filaments
rate limiting step on initiation
initial polymerization of three actin monomers
profilin
stimulates exchange of ADP for ATP; associated with formin