Type II cAMP-dependent protein kinase is associated with the rabbit kidney brush border membranes.

Photolabelling with 32P-8-azido-cAMP identified a major cAMP-binding protein (54 kDa) in isolated rabbit renal apical membranes, whose labelling was competitively inhibited by cAMP. Membrane associated cAMP-binding polypeptides were extensively purified by affinity chromatography on cAMP-Sepharose. The 54 kDa polypeptide represented 70-80% of the total protein eluted with cAMP. This protein was rapidly phosphorylated by the catalytic subunit of cAMP-dependent protein kinase, with a shift in its apparent mobility on SDS-PAGE to Mr 56/58,000. The phosphopeptide maps of autophosphorylated rat skeletal muscle RII and rabbit kidney 56/58 kDa proteins were essentially identical. Western immuno-blot analysis, using antibodies generated against purified rat RI and RII, indicated preferential cross-reactivity of rabbit kidney 54 kDa protein with anti-RII antibodies. The data demonstrates the specific association of the regulatory subunit of type II cAMP dependent protein kinase with rabbit renal brush border membranes.

Duke Scholars

Author Shirish Shenolikar Psychiatry & Behavioral Sciences, Behavioral Medicine & Neur ...