Immuno-electron Microscopy of αvβ3 Integrin Localization in Osteoblasts

Abstract

Subcellular localization of vitronectin receptors (integrin αvβ3 subunits) in rat osteoblasts was examined by means of light and post-embedding, immuno-electron microscopy. The specific immunoreactivity for the cytoplasmic domain of integrin αv and β3 subunits, detected by using colloidal gold-conjugated secondary antibody, was clearly observed along the plasma membranes and in the cisterns of rough-surfaced endoplasmic reticulum and secretory granules of osteoblasts. Such immunoreactivity was hardly detected by a protein A-gold technique. Obtained results suggest that αvβ3 integrin has a role in osteoblast-bone matrix interactions including the induction of cytoplasmic polarity, cell differentiation, cell-matrix adhesion, and bone formation processes.