A family of gamma-like calcium channel subunits

The gamma subunit was initially identified as an auxiliary subunit of the s keletal muscle calcium channel complex. Evidence for the existence of furth er gamma subunits arose following the characterization of a genetic defect that induces epileptic seizures in stargazer mice, We present here the firs t account of a family of at least five putative gamma subunits that are pre dominantly expressed in brain. The gamma-2 and gamma-4 subunits shift the s teady-state inactivation curve to more hyperpolarized potentials upon coexp ression with the P/Q type alpha(1A) subunit, The coexpression of the gamma- 5 subunit accelerates the time course of current activation and inactivatio n of the alpha(1G) T-type calcium channel. (C) 2000 Federation of European Biochemical Societies.