The voltage-gated calcium channel gamma subunits: a review of the literature.

Members of the voltage-gated calcium channel y subunit gene family (Cacng), have been rapidly discovered since the discovery of the identification of the mouse gamma2 gene (Cacng2) and its association with the stargazer mutant mouse line. The fact that this mutant mouse line exists has allowed researchers to gain insights into the function of the gamma2 subunit. For example, stargazer mice have elevated levels of neuropeptide Y production, very low cerebellar brain derived neurotrophic factor production, and diminished cerebellar GABAA alpha6 and beta3 production. Study of this mutant mouse line has also revealed that the gamma2 subunit is involved in AMPA receptor trafficking and targeting to the synaptic membrane. For the most part, the effect of gamma2 subunits on the electrophysiology of voltage-gated calcium channels is to downregulate calcium channel activity by causing a hyperpolarizing shift in the inactivation curve. This finding and the association of these subunits with AMPA receptor trafficking has led some researchers to question the actual role of the gamma subunits. This article reviews the discovery, cellular localization, tissue distribution, and function of the eight members of the Cacng family.