actin Flashcards
what are actin filaments?
microfilaments - helical polymers of protein actin
what are actin subunits?
called globular or G-actin
a polypeptide carry8ing ATP or ADP
what does actin assembly provide?
polarity to the filament (- end = atp-binding pocket exposed, + end = atp-binding pocket is buried
where does growth happen in actin?
in the + end mostly
what purpose does nucleation have?
is it the rate-limiting step in formation of actin filaments
what affect does numner of actin molecules bonding have?
two molecules are a weak bond, three is more stable
what is phalloidin?
drug that stabalizes F-actin
what are filopodia and lamellipodia?
protrusive structures made by migrating cells
what do actin-binding proteins do?
regulate polymerization and length of filaments
where do capping proteins bind?
to the + ends of actin
what does cofilin do?
cuts actin filaments into small pieces
what does actin crosslinking makes?
complex structures such as filopodia and lamellipodium
what is alpha-actinin?
a crosslinking protein that makes F-actin bundles (a rigid dimer)
what is filamin?
a flexible actin crosslinker protein (flexible dimer)
what is the Arp2/3 complex?
made of 7 subunits similar to G-actin
promotes actin branching by binding to the side of ta filament and recruiting actin monomers
