Endocrinology, Vol 120, 170-177, Copyright © 1987 by Endocrine Society

ARTICLES

Calcium-calmodulin-dependent protein kinase in hyperplastic human parathyroid glands

BK Kinder, NG Delahunt, JD Jamieson and FS Gorelick

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.

This article has been cited by other articles:

				L. M. Matovcik, S. S. Rhee, J. F. Schaefer, and B. K. Kinder Reconstitution of Calcium-Regulated Parathyroid Hormone Secretion from Streptolysin-O-Permeabilized Parathyroid Cells by Guanosine 5'-O-(Thio)Triphosphate Endocrinology, March 1, 1997; 138(3): 1170 - 1179. [Abstract] [Full Text] [PDF]