PDE6D and cancer: Modulatingmembrane localization of small G proteins has had a high profile sincefarnesyl transferase inhibitors were trialled to suppress Ras activityin cancers.38 Although these inhibitorsnever progressed to clinical utility, renewed interest in preventingmembrane localization has re-emerged more recently with the discoverythat PDEδ acts as a GDI-like molecule for Ras39 and the identification of small molecule inhibitors ofPDEδ with biological activity.40