BIOL 201 Lecture 13: BIOL 201 cell biology and metabolism lecture 13
Document Summary
A dimer with 2 actin binding domains fh1 and fh2. The domains can and shift upwards to open the binding site and let new actin join. The alternating between 2 domains joins actin constantly and extend the filament (in the positive direction) Can form very long actin filament before detaching. Can regulate the rate of actin growth by controlling how fast the dimer shifts. Bind to minus end of actin filament and induces disintegration of the filament, separate it into individual actin units: profilin recycles actin and blocks minus end polymerization. When an actin monomer leaves the minus end, it is in adp binding state. Profilin bind to adp-actin, block its minus end binding site. Atp-actin can bind to the positive end of a filament: thymosin-b4 keeps actin in reserve (keep then inactive, out of the treadmilling cycle, together cofilin and profilin accelerate actin treadmilling. Prevent futile polymerization, and running out of actin units.
