Substoichiometric Amounts of Aip1p
Accelerate the Disassembly
of Cofilin-Decorated Actin Filaments
Shown below is an actin filament pelleting
assay: actin purified from yeast was induced to polymerize with
salt and magnesium in the presence of stoichiometric amounts of
cofilin and varying amounys of Aip1p. The filaments are then pelleted
and the supernatant versus the pellet is sampled in a coomassie
stained gel to quantify the amount of actin present in the filamentous
form. As can be seen in lane 1, actin efficiently forms filaments
in the presence of cofilin and these filaments are fully bound
by cofilin as evidenced by the presence of cofilin in the pellet
phase. The addition of Aip1p at a 1:5 stoichiometry causes a large
decrease in actin from the pellet phase. Even a 1:200 ratio of
Aip1p to actin and cofilin leads to a measurable decrease in filaments
(lane 6) This assay shows that Aip1p can act to destabilize cofilin-decorated
actin filaments even when present at vastly substoichiometric
levels.
