Effects of the low-molecular-weight GTP-binding protein RhoA on calcium waves in xenopus oocytes.

In normal Xenopus oocytes, injection of high concentrations of inositol-1,4,5-trisposphate (IP3) always elicited a Ca2+ wave, which propagated from the injection site toward the opposite side of the oocyte. In oocytes injected with C3 toxin, a specific blocker of RhoA, a similar Ca2+ wave was still observed, but propagation of the wave appeared to be retarded compared with normal controls. This apparent retardation seemed to be due to a slower decrease of normally increased Ca2+ rather than to a slower increase of Ca2+. It is suggested that RhoA may play a role in Ca2+ reuptake mechanisms.