EXPRESSION AND CHARACTERIZATION OF THE ALPHA-SUBUNIT OF CA-2+ CALMODULIN-DEPENDENT PROTEIN KINASE-II USING THE BACULOVIRUS EXPRESSION SYSTEM

Sf9 cells infected with the recombinant mouse CaMKII-α (Ca2+/calmodulin dependent kinase II) baculovirus expressed 12-15 mg of MCaMKII-α per liter of cells. Approximately 50% of the MCaMKII-α activity could be purified using a CaM-Sepharose affinity column. The purified MCaMKII-α had a Mrapp of 50 kDa by SDS-PAGE and a native Mr of 600 kDa. MCaMKII-α, like rat brain CaMKII, had an A0.5 for CaM of 100 nM, a Km for syntide-2 of 8 μM, and was able to generate Ca2+-independent activity by autophosphorylation. The baculovirus system expressed large quantites of MCaMKII-α with characteristics similar to the rat brain CaMKII, thus providing an expression system for the detailed biochemical analysis of MCaMKII-α. © 1990 Academic Press, Inc.