Consensus nomenclature for the human ArfGAP domain-containing proteins.

At the FASEB summer research conference on "Arf Family GTPases", held in Il Ciocco, Italy in June, 2007, it became evident to researchers that our understanding of the family of Arf GTPase activating proteins (ArfGAPs) has grown exponentially in recent years. A common nomenclature for these genes and proteins will facilitate discovery of biological functions and possible connections to pathogenesis. Nearly 100 researchers were contacted to generate a consensus nomenclature for human ArfGAPs. This article describes the resulting consensus nomenclature and provides a brief description of each of the 10 subfamilies of 31 human genes encoding proteins containing the ArfGAP domain

Stimulation of L-type Ca2+ channels by inositol pentakis- and hexakisphosphates in rat vascular smooth muscle cells

The electrophysiological effects of d-myo-inositol 1,3,4,5,6-pentakisphosphate (InsP5) and d-myo-inositol hexakisphosphate (InsP6), which represent the main cellular inositol polyphosphates, were studied on L-type Ca2+ channels in single myocytes of rat portal vein. Intracellular infusion of InsP5 (up to 50 μm) or 10 μm InsP6 had no action on Ba2+ current, whereas 50 μm InsP6 or 10 μm InsP5 plus 10 μm InsP6 (InsP5,6) stimulated the inward current. The stimulatory effect of InsP5,6 was also obtained in external Ca2+-containing solution. The stimulated Ba2+ current retained the properties of L-type Ba2+ current and was oxodipine sensitive. PKC inhibitors Ro 32-0432 (up to 500 nm), GF109203X (5 μm) or calphostin C (100 nm) abolished the InsP5,6-induced stimulation. Neither the PKA inhibitor H89 (1 μm) nor the protein phosphatase inhibitors okadaic acid (500 nm) or cypermethrin (1 μm) prevented or mimicked the InsP5,6-induced stimulation of Ba2+ current. However, InsP5 or InsP6 could mimic some effects of protein phosphatase inhibitor so as to extend after washing-out forskolin the stimulatory effects of the adenylyl cyclase activator on Ba2+ current. These results indicate that InsP5 and InsP6 may act as intracellular messengers in modulating L-type Ca2+ channel activity and so could be implicated in mediator-induced contractions of vascular smooth muscle cells