Rac1 gets fattier

Since its description more than two decades ago as a substrate for botulinum C3 exoenzyme (Didsbury et al, 1989), Rac1 has been one of the most studied small GTPases of the Ras superfamily. Interest in Rac1 exploded in 1992 when Ridley and Hall published their seminal work showing that Rac1 regulates the actin cytoskeleton to promote lamellipodia formation (Ridley et al, 1992). Since that report, >4350 studies have been published on Rac1 and seemingly every detail of its regulation and biological function has been dissected, including its post-translational modifications. It therefore comes as somewhat of a surprise when del Pozo and colleagues (Navarro-Lerida et al, 2012) report for the first time in this issue of The EMBO Journal that Rac1 can be palmitoylated and that acylation directs its location in plasma membrane microdomains and modulates its signalling output.