E-cadherins identified in osteoblastic cells: effects of parathyroid hormone and extracellular calcium on localization.
The presence and regulation of cadherin localization in osteoblastic cells were examined. Monoclonal antibody (ECCD-1) that interferes with E-cadherin function prevented cell adhesion in UMR 106-H5 rat osteosarcoma cells and non-tumorigenic mouse calvarial MC3T3-E1 cells, whereas CCL39 fibroblast adhesion was not affected. Immunofluorescent antibodies (ECCD-2 and polyclonal L-CAMP P1) revealed cadherins are localized along the osteoblastic cell-cell boundaries. Exposure of UMR 106-H5 cells to bovine parathyroid hormone (1-84) (PTH; 10 ng/ml x 1 hr) or low calcium medium (1.0-0.025 mM) produced cellular retraction accompanied by intense immunofluorescence for cadherins throughout cells with a corresponding loss of punctate localization at remaining cell-cell adhesion points. Western immunoblot analysis indicated 108 kd and 115 kd cadherins are present, with a smaller 29.5 kd band that became predominantly associated with the cytosolic fraction of cells treated with parathyroid hormone or lowered calcium. The results demonstrate E-like cadherins are present in osteoblastic cells and implicate a regulatory role for parathyroid hormone and calcium in cadherin function and localization.
Babich
M
M
Department of Biomedical Sciences, University of Illinois College of Medicine, Rockford 61107-1897.
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D016475:3T3 Cells; D000818:Animals; D016723:Bone Remodeling / Q000502:physiology*; D015820:Cadherins / Q000032:analysis* / Q000502:physiology; D002118:Calcium / Q000502:physiology; D002450:Cell Communication; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D004591:Electrophoresis, Polyacrylamide Gel; D005347:Fibroblasts; D005455:Fluorescent Antibody Technique; D051379:Mice; D010006:Osteoblasts / Q000737:chemistry*; D010281:Parathyroid Hormone / Q000502:physiology; D051381:Rats; D014407:Tumor Cells, Cultured
D015820:Cadherins; D010281:Parathyroid Hormone; D002118:Calcium