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Identification of a Membrane Receptor for 1,25‐Dihydroxyvitamin D 3 Which Mediates Rapid Activation of Protein Kinase C
Author(s) -
Nemere I.,
Schwartz Z.,
Pedrozo H.,
Sylvia V. L.,
Dean D. D.,
Boyan B. D.
Publication year - 1998
Publication title -
journal of bone and mineral research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.882
H-Index - 241
eISSN - 1523-4681
pISSN - 0884-0431
DOI - 10.1359/jbmr.1998.13.9.1353
Subject(s) - protein kinase c , biology , receptor , vesicle , chondrocyte , protein kinase a , microbiology and biotechnology , g protein , binding protein , biochemistry , membrane , kinase , in vitro , gene
This paper is the first definitive report demonstrating a unique membrane receptor for 1,25‐dihydroxyvitamin D 3 (1,25(OH) 2 D 3 ) which mediates the rapid and nongenomic regulation of protein kinase C (PKC). Previous studies have shown that 1,25(OH) 2 D 3 exerts rapid effects on chondrocyte membranes which are cell maturation‐specific, do not require new gene expression, and do not appear to act via the traditional vitamin D receptor. We used antiserum generated to a [ 3 H]1,25(OH) 2 D 3 binding protein isolated from the basal lateral membrane of chick intestinal epithelium (Ab99) to determine if rat costochondral resting zone (RC) or growth zone (GC) cartilage cells contain a similar protein and if cell maturation‐dependent differences exist. Immunohistochemistry demonstrated that both RC and GC cells express the protein, but levels are highest in GC. The binding protein is present in both plasma membranes and matrix vesicles and has a molecular weight of 66,000 Da. The 66 kDa protein in GC matrix vesicles has a K d of 17.2 fmol/ml and B max of 124 fmol/mg of protein for [ 3 H]1,25(OH) 2 D 3 . In contrast, the 66 kDa protein in RC matrix vesicles has a K d of 27.7 fmol/ml and a B max of 100 fmol/mg of protein. Ab99 blocks the 1,25(OH) 2 D 3 ‐dependent increase in PKC activity in GC chondrocytes, indicating that the 1,25(OH) 2 D 3 ‐binding protein is indeed a receptor, linking ligand recognition to biologic function.