Rho GTPase Activating Protein (RICS)

RICS is a neuron-associated GTPase-activating protein that may regulate dendritic spine morphology and strength by modulating Rho GTPase activity .

It is thought that CaMKII activated by Ca2+ entry through NMDA receptors inactivates RICS through phosphorylation, which in turn increases the active GTP-bound forms of Cdc42 and Rac1. This would thereby induce, for example, remodeling of dendritic spines. Because it has been shown in some experiments that Cdc42 does not affect spine morphology, whilst others have shown that Rac1 does, the most likely pathway is via Rac1. That RACS also binds to B-Catenin and N-cadherins, in vivo within the PSD suggests that there may be another pathway for it modifying spine structure as well .