Fig. S8.

Interactions between profilin and the G-actin/N-actin complex. Five micromolar GST-tagged profilin was immobilized GST-resin and mixed with 10 μM G-actin or the N-actin complex. After washing, the bound materials were eluted and analyzed with SDS/PAGE. The HSA domain polypeptide (<10 kDa) ran out of the gel. G-actin was notably bound to profilin (lane 4), whereas little N-actin was retained by profilin (lane 7). The faint actin band in lane 7 suggested profilin competed with Arp4/HSA in binding to N-actin and led to partial disassembly of the N-actin complex, as indicated by the absence of Arp4 in the elution fraction.