Annexin II is the membrane receptor that mediates the rapid actions of 1alpha,25-dihydroxyvitamin D(3).
1alpha,25-Dihydroxyvitamin D(3) has been shown to exert its effects by both genomic (minutes to hours) and rapid (seconds to minutes) mechanisms. The genomic effects are mediated by interaction with the nuclear vitamin D receptor. We show that the vitamin D analog, [(14)C]-1alpha,25-dihydroxyvitamin D(3) bromoacetate, is specifically bound to a protein (molecular weight 36 kDa) in the plasma membrane of rat osteoblastlike cells (ROS 24/1). The plasma membrane protein labeled with the bromoacetate analog was identified as annexin II by sequence determination and Western blot. Partially purified plasma membrane proteins (PI 6.9-7.4) and purified annexin II exhibited specific and saturable binding for [(3)H]-1alpha, 25-dihydroxyvitamin D(3). Antibodies to annexin II inhibited [(14)C]-1alpha,25-dihydroxyvitamin D(3) bromoacetate binding to ROS 24/1 plasma membranes, immunoprecipitated the ligand-protein complex, and inhibited 1alpha,25-dihydroxyvitamin D(3)-induced increases in intracellular calcium in ROS 24/1 cells. The results indicate that annexin II may serve as a receptor for rapid actions of 1alpha, 25-dihydroxyvitamin D(3).
Baran
D T
DT
Department of Orthopedics, University of Massachusetts Medical School, Worcester 01655, USA.
Quail
J M
JM
Ray
R
R
Leszyk
J
J
Honeyman
T
T
D000818:Animals; D017306:Annexin A2 / Q000737:chemistry / Q000187:drug effects / Q000502:physiology*; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D002117:Calcitriol / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000493:pharmacokinetics; D002250:Carbon Radioisotopes; D002462:Cell Membrane / Q000502:physiology; D007700:Kinetics; D010006:Osteoblasts / Q000187:drug effects / Q000502:physiology*; D012516:Osteosarcoma; D011869:Radioligand Assay; D051381:Rats; D018167:Receptors, Calcitriol / Q000037:antagonists & inhibitors / Q000502:physiology*; D014316:Tritium; D014407:Tumor Cells, Cultured
C104313:1,25-dihydroxyvitamin D3-3-bromoacetate; D017306:Annexin A2; D000911:Antibodies, Monoclonal; D002250:Carbon Radioisotopes; D018167:Receptors, Calcitriol; D014316:Tritium; D002117:Calcitriol