Calcium-calmodulin-dependent protein kinase in hyperplastic human parathyroid glands.
The function of the parathyroid gland is closely linked to intracellular and extracellular Ca2+ concentrations. As a step toward understanding the mechanism of action of Ca2+ on the parathyroid, we examined hyperplastic human parathyroid tissue for Ca2+ and calmodulin-dependent protein kinase activity. In parathyroid homogenates, Ca2+ stimulates the phosphorylation of substrate protein in the presence of calmodulin or phospholipid. The calmodulin (CaM)-stimulated activity is present in a soluble fraction of parathyroid and can be separated from other protein kinase activities by gel filtration chromatography. The concentration dependence of CaM kinase on Ca2+ and CaM was determined using the gel filtration. The Ka values for CaM and calcium were 100 nM and 5 microM, respectively. The fraction containing the CaM kinase activity had a calculated mol wt of 5.5 X 10(5). It contained a protein with a mol wt of 4.9 X 10(4) whose phosphorylation was Ca2+ CaM dependent and a CaM-binding protein of mol wt 4.9 X 10(4) which we suggest may be the catalytic subunit of a type II Ca2+-CaM dependent protein kinase. Hyperplastic human parathyroid tissue contains a type II Ca2+-CaM dependent protein kinase which may serve an important function in Ca2+-directed metabolism.
D002118:Calcium / Q000502:physiology; D002147:Calmodulin / Q000502:physiology; D002148:Calmodulin-Binding Proteins / Q000378:metabolism; D006801:Humans; D006965:Hyperplasia; D009419:Nerve Tissue Proteins / Q000378:metabolism; D010280:Parathyroid Glands / Q000201:enzymology* / Q000473:pathology; D010750:Phosphoproteins / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism*; D038601:Ribosomal Protein S6; D012269:Ribosomal Proteins / Q000378:metabolism; D016704:Synapsins
D002147:Calmodulin; D002148:Calmodulin-Binding Proteins; D009419:Nerve Tissue Proteins; D010750:Phosphoproteins; D038601:Ribosomal Protein S6; D012269:Ribosomal Proteins; D016704:Synapsins; D011494:Protein Kinases; D002118:Calcium