GENETIC-ANALYSIS OF BETA-1 INTEGRIN FUNCTION - CONFIRMED, NEW AND REVISED ROLES FOR A CRUCIAL FAMILY OF CELL-ADHESION MOLECULES

Integrins are heterodimeric cell adhesion proteins connecting the extr acellular matrix to the cytoskeleton and transmitting signals in both directions, These integrins are suggested to be involved in many diffe rent biological processes such as growth, differentiation, migration, and cell death, Of more than 20 known integrins, 10 contain the nearly ubiquitously expressed beta 1 integrin subunit, Disruption of the bet a 1 integrin gene by homologous recombination allows us to assess the supposed functions of beta 1 containing integrins in vivo in a new way , This review will present and discuss recent findings derived from su ch studies concerning the biological roles of beta 1 integrins in earl y development, differentiation and migration, hematopoiesis, tumorigen esis, and supramolecular assembly of extracellular matrix proteins, Wh ile several former results were confirmed, others were contradicted an d new functions found, significantly changing the previous view of bet a 1 integrin function in vivo.