ADP-RIBOSYLATION OF RHO ENHANCES ACTIN POLYMERIZATION-COUPLED SHAPE OSCILLATIONS IN HUMAN NEUTROPHILS

Stimulated neutrophils exhibit coordinated sinusoidal oscillations in filamentous actin content and cellular shape. We investigated the effe ct of inhibition of the small G protein Rho on neutrophil actin polyme rization, shape changes and oscillations using a genetically engineere d toxin that enters cells and selectively ADP-ribosylates endogenous R ho. This treatment increased the amplitudes and frequencies of shape o scillations and duration of the oscillating transient. However, it had no effect on the initial actin polymerization and shape changes induc ed by N-formyl-Met-Leu-Phe. Regulation of these oscillations may be im portant for the control of neutrophil motility.