Immunocytochemical localization of protein kinases and calmodulin in dog thyroid cells

By immunocytochemical methods, the protein effectors of known intracellular signal molecules were demonstrated in the thyroid follicular cell and their localization investigated. Cyclic AMP protein kinase subunit RII was clearly located in the nucleus. Protein kinase subunits RI and C were in the cytosol and on the apical membrane. Cyclic GMP kinase and calmodulin were mostly found in the cytoplasm and at the apical membrane; they were poorly represented in the nucleus. The only membrane underlined by several markers was the apical membrane, i.e. the site of iodination, oxido reduction and H2O2 generation.