FIG. 7.

Phosphorylation at Ser-137 inhibits profilin as an aggregation suppressor in primary neurons. Rat embryonic cortical neurons were cotransfected with Htt exon 1(Q72) YFP with either an empty vector or different profilin constructs (wt, S137A, or S137D). Cells were cultured for 4 days and fixed prior to counting inclusions in 10 to 20 fields per coverslip. (A) Representative images of transfected cells showing inclusions formed by Htt exon 1(Q72) YFP (magnification, ×10). Profilin(wt) and profilin(S137A) each reduced the number of inclusions, while profilin(S137D) did not. (B) Averages of three independent experiments showing the effect of profilin expression on inclusion formation. The y axis represents relative inclusion numbers normalized against those in the cells cotransfected with the empty vector. Profilin(wt) and profilin(S137A) each reduced inclusions, whereas profilin(S137D) did not (*, P < 0.05 by paired t test).