Phosphorylation of the? subunit of the sodium channel by protein kinase C

Abstract
1. Theα subunit of the purified voltage-sensitive sodium channel from rat brain is rapidly phosphorylated to the extent of 3–4 mol phosphate/mol by purified protein kinase C. 2. Theα subunit of the native sodium channel in synaptosomal membranes is also phosphorylated by added protein kinase C as assessed by specific immunoprecipitation and polyacrylamide gel electrophoresis of labeled membranes. 3. Our results suggest coordinate regulation of sodium channel phosphorylation state by cAMP-dependent and calcium/phospholipid-dependent protein kinases.