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          Institute: MPI für molekulare Physiologie     Collection: Abteilung II - Systemische Zellbiologie     Display Documents

ID: 427502.0, MPI für molekulare Physiologie / Abteilung II - Systemische Zellbiologie
Physical state of the extracellular matrix regulates the structure and molecular composition of cell-matrix adhesions
Authors:Katz, B. Z.; Zamir, E.; Bershadsky, A.; Kam, Z.; Yamada, K. M.; Geiger, B.
Date of Publication (YYYY-MM-DD):2000-03
Title of Journal:Molecular Biology of the Cell
Journal Abbrev.:Mol Biol Cell
Issue / Number:3
Start Page:1047
End Page:1060
Review Status:not specified
Audience:Not Specified
Abstract / Description:This study establishes that the physical state of the extracellular matrix can regulate integrin-mediated cytoskeletal assembly and tyrosine phosphorylation to generate two distinct types of cell-matrix adhesions. In primary fibroblasts, alpha(5)beta(1) integrin associates mainly with fibronectin fibrils and forms adhesions structurally distinct from focal contacts, independent of actomyosin-mediated cell contractility. These "fibrillar adhesions" are enriched in tensin, but contain low levels of the typical focal contact components paxillin, vinculin, and tyrosine-phosphorylated proteins. However, when the fibronectin is covalently linked to the substrate, alpha(5)beta(1) integrin forms highly tyrosine-phosphorylated, "classical" focal contacts containing high levels of paxillin and vinculin. These experiments indicate that the physical state of the matrix, not just its molecular composition, is a critical factor in defining cytoskeletal organization and phosphorylation at adhesion sites. We propose that molecular organization of adhesion sites is controlled by at least two mechanisms: 1) specific integrins associate with their ligands in transmembrane complexes with appropriate cytoplasmic anchor proteins (e.g., fibronectin-alpha(5)beta(1) integrin-tensin complexes), and 2) physical properties (e.g., rigidity) of the extracellular matrix regulate local tension at adhesion sites and activate local tyrosine phosphorylation, recruiting a variety of plaque molecules to these sites. These mechanisms generate structurally and functionally distinct types of matrix adhesions in fibroblasts.
Free Keywords:*Cell Adhesion; Cell Movement; Cells, Cultured; Extracellular Matrix/*chemistry/physiology; Fibroblasts/cytology/physiology; Fibronectins/physiology; Humans; Phosphotyrosine/metabolism
External Publication Status:published
Document Type:Article
Communicated by:Jürgen Block
Affiliations:MPI für molekulare Physiologie/Abteilung II - Systemische Zellbiologie/AG Dr. E. Zamir
External Affiliations:%G eng
Identifiers:ISSN:1059-1524 (Print) [ID No:1]
URL:http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=... [ID No:2]
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