HS1 stabilizes branched actin filaments at the leading edge of DCs. (a) Structure
of HS1. The NTA domain, shown in red, binds to the Arp 2/3 complex. The
helix-turn-helix domain and coiled-coil domains, shown in blue, bind to F-actin.
A proline rich domain, SH3 domain and important tyrosine residues are located at
the C-terminus. (b) Cartoon representation of branched actin structure in
lamellipodia. Red represents the Arp 2/3 Complex and blue represents actin. HS1
(chain of colored circles) is thought to stabilize actin branch points by
simultaneously binding the Arp 2/3 Complex and neighboring F-actin.