This study describes the adhesion of human osteoblasts, cultured in vitro, to proteins of the extracellular matrix, the biosynthesis of integrins, their topography and organization in focal contacts. The adhesion of osteoblasts to laminin, type I collagen, vitronectin and fibronectin was 77-100%, in 2 h and at 55 nM substrata concentration, and it was accompained by spreading of the cells. Adhesion to fibronectin (FN), laminin (LN) and type I collagen (COL) was inhibited by antibodies to the ß1 integrin and antibodies to the a5 chain affected adhesion only to fibronectin. Using a panel of polyclonal antibodies against a2, a3, a5, av, ß1 and ß3 integrins we detected synthesis of a3ß1, a5ß1, avß3, and an avß1-like dimer by immunoprecipitation of metabolically labelled cell lysates. Studies of immunolocalization demonstrated the presence of the same integrins identified in lysates, plus a4, a1 and ß5 subunits. In cells adhering in the presence of serum we showed organization of ß3 and av integrins in focal contacts. In cells adhering to fibronectin a5 and ß1 integrins were localized in focal contacts. In cells spread on laminin or type I collagen none of the integrins investigated was localized in focal contacts.

Integrin synthesis and utilization in cultured human osteoblasts

SANGUINETI, FRANCESCA;
1996-01-01

Abstract

This study describes the adhesion of human osteoblasts, cultured in vitro, to proteins of the extracellular matrix, the biosynthesis of integrins, their topography and organization in focal contacts. The adhesion of osteoblasts to laminin, type I collagen, vitronectin and fibronectin was 77-100%, in 2 h and at 55 nM substrata concentration, and it was accompained by spreading of the cells. Adhesion to fibronectin (FN), laminin (LN) and type I collagen (COL) was inhibited by antibodies to the ß1 integrin and antibodies to the a5 chain affected adhesion only to fibronectin. Using a panel of polyclonal antibodies against a2, a3, a5, av, ß1 and ß3 integrins we detected synthesis of a3ß1, a5ß1, avß3, and an avß1-like dimer by immunoprecipitation of metabolically labelled cell lysates. Studies of immunolocalization demonstrated the presence of the same integrins identified in lysates, plus a4, a1 and ß5 subunits. In cells adhering in the presence of serum we showed organization of ß3 and av integrins in focal contacts. In cells adhering to fibronectin a5 and ß1 integrins were localized in focal contacts. In cells spread on laminin or type I collagen none of the integrins investigated was localized in focal contacts.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11567/479919
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