Integrins are a family of cell adhesion receptors composed of 24 αβ heterodimeric members, which play crucial roles in developmental and pathological processes. These receptors mediate cell attachment to the extracellular matrix (ECM) and participate in specialized cell-cell interactions. Only a subset of integrins (8 out of 24) recognizes the RGD sequence in native ligands, while others recognize alternative sequences such as GFOGER in collagen. The αI domain is present in nine integrin chains and is involved in collagen binding. Integrins can exist in different conformations, and their activation is regulated by various factors, including mechanical tension and signaling pathways. Integrin ligands include major ECM constituents like fibronectin, vitronectin, and fibrinogen, as well as basement membrane proteins like laminin. Integrins also bind to proteolytic fragments of ECM proteins, such as endostatin, tumstatin, and endorepellin. Integrins function as mechanical links between the ECM and the cytoskeleton, and they serve as bidirectional signaling receptors, mediating both inside-out and outside-in signaling. Their expression is dynamic and regulated by various factors, and they are essential for various cellular functions, including stem cell maintenance and differentiation.Integrins are a family of cell adhesion receptors composed of 24 αβ heterodimeric members, which play crucial roles in developmental and pathological processes. These receptors mediate cell attachment to the extracellular matrix (ECM) and participate in specialized cell-cell interactions. Only a subset of integrins (8 out of 24) recognizes the RGD sequence in native ligands, while others recognize alternative sequences such as GFOGER in collagen. The αI domain is present in nine integrin chains and is involved in collagen binding. Integrins can exist in different conformations, and their activation is regulated by various factors, including mechanical tension and signaling pathways. Integrin ligands include major ECM constituents like fibronectin, vitronectin, and fibrinogen, as well as basement membrane proteins like laminin. Integrins also bind to proteolytic fragments of ECM proteins, such as endostatin, tumstatin, and endorepellin. Integrins function as mechanical links between the ECM and the cytoskeleton, and they serve as bidirectional signaling receptors, mediating both inside-out and outside-in signaling. Their expression is dynamic and regulated by various factors, and they are essential for various cellular functions, including stem cell maintenance and differentiation.