The neglected terminators: Rho family GAPs in neutrophils

GTPase-activating proteins (GAPs) accelerate the rate of hydrolysis of GTP bound to small GTPases, thereby limiting the prevalence and concentration of the active, GTP-bound form of these proteins. The large number of potential GAPs acting on members of the Rho family of small GTPases raises the question of specificity or redundancy.

In this review, we summarize experimental data obtained on the role of Rho family GAPs in neutrophils, highlight cases where more than one GAP is involved in a physiological function and show examples that GAPs can be involved not only in termination but also in initiation of cellular processes. We demonstrate that the expression-level regulation of GAPs may also occur in short-living cells such as neutrophils. Finally, we provide insight into the existence and structure of molecular complexes in which Rho family GAPs are involved.

GAPs play more complex and varied roles than being simple terminators of cellular processes.