One of the three subtypes of rho GTPases in the ras superfamily of small G proteins (the others are rho and cdc42). They are substrates for botulinum toxin C3 ADP-ribosylation. The active GTP-bound form of rac seems to induce membrane ruffling in motile cells, whereas rho acts on stress fibres. Chimerins are rac-specific GTPase activating proteins (rac-*GAPs).
Subjects: Medicine and Health.