Identification of two subclasses of type II cAMP-dependent protein kinases. Neural-specific and non-neural protein kinases.
Jack Erlichman, D. Sarkar, Nikoline Leo Fleischer, C S Rubin · Journal of Biological Chemistry · 1980
Antiserum raised against the regulatory subunit of type I1 CAMP-dependent protein kinase from bovine cerebral cortex was used to identify and distinguish two subclasses of cytosolic protein kinases.Rabbit antibrain R I1 immunoglobulins bound both intact type I1 protein kinase and dissociated R I1 subunits from central nervous system and neuroendocrine tissues with high affinity as documented in quantitative immunoprecipitation experiments and radioimmunoassays.This antiserum did not react with dissociated catalytic subunits.In competitive binding radioimmunoassays type I1 CAMP-dependent protein kinases from several brain regions and neuroendocrine glands were 15-to 30-fold more potent than their non-neural counterparts in displacing tracer '"1-brain R I1 from anti-brain R I1 LgG.All the neural kinases were equipotent, achieving 50% displacement a t 30 n~ R 11.In contrast, minimal levels of displacement (0 to 10%) were observed when type 11 kinases from skeletal muscle, heart, liver, and kidney were employed at 30 n~ R II.Parallel results were obtained in immunoprecipitation experiments; 25 nl of anti-brain R I1 serum were sufficient to complex 50% of the CAMP-binding activity in samples containing 0.8 pmol of brain protein kinase 11, while 400 to 500 nl were required for comparable R 11.antibody complex formation when 0.8 pmol of heart protein kinase I1 was employed.Anti-brain R 11 IgG also differentially affected a functional property of R I1 subunits.When added to type I1