Integrin beta-1 (ITGB1), also named as CD29, is a 130 kDa single chain type I glycoprotein that is expressed in a heterodimeric complex with one of six distinct α subunits, comprising the very late activation antigen (VLA) subfamily of adhesion receptors. It is one of the essential surface molecules expressed on human MSC from bone marrow and other sources. The β1 subunit is also broadly expressed on lymphocytes and monocytes, weakly expressed on granulocytes, and not expressed on erythrocytes. These receptors are involved in a variety of cell-cell and cell-matrix interactions.