Localization of cyclic AMP-dependent protein kinase subunits in rat hepatocyte nuclei by immunogold electron microscopy.
We have applied the indirect colloidal immunogold technique to examine the ultrastructural localization of the catalytic subunit C and the regulatory subunits RI and RII of cyclic AMP-dependent protein kinase in rat hepatocyte nuclei before and after glucagon or dibutyryl cyclic AMP administration. The technique allowed the identification and localization of all three subunits in hepatocyte nuclei. Morphometric quantitation of the relative staining density of nuclear subunits indicated an increase of immunogold staining of nuclear catalytic subunit but not of the regulatory subunits after glucagon or dibutyryl cyclic AMP stimulation. The increase of catalytic subunit occurred in a biphasic manner with peak levels 2-30 min and 90-150 min after stimulation. Our experiments represent the first reported use of the immunogold procedure to identify and localize protein kinase subunits in the nucleus.
D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002352:Carrier Proteins / Q000032:analysis; D002467:Cell Nucleus / Q000032:analysis*; D005934:Glucagon / Q000494:pharmacology; D006046:Gold; D007124:Immunoenzyme Techniques; D047908:Intracellular Signaling Peptides and Proteins; D008099:Liver / Q000032:analysis*; D008297:Male; D008854:Microscopy, Electron; D011493:Protein Kinase C; D011494:Protein Kinases / Q000032:analysis*; D051381:Rats; D011919:Rats, Inbred Strains
D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; C015482:protein kinase modulator; D003994:Bucladesine; D006046:Gold; D005934:Glucagon; D011494:Protein Kinases; D011493:Protein Kinase C