Integrin alpha-2 beta-1 (ITGA2-ITGB1)

Integrin alpha-2 beta-1 (ITGA2/ITGB1) is a transmembrane heterodimeric receptor that serves as a primary mediator for the attachment of osteogenic cells to the extracellular matrix, specifically recognizing the cell-binding domains of Type I collagen (Hennessy et al., 2003, PubMed: 17613031). In therapeutic contexts, this receptor is the molecular target for "osteogenic cell binding peptides" such as P-15, a synthetic 15-amino acid sequence that mimics the alpha-1(I) chain of collagen (Bhatnagar et al., 1999, PubMed: 10403401). Upon binding, the receptor triggers intracellular signaling pathways, including focal adhesion kinase (FAK) and mitogen-activated protein kinase (MAPK), which promote osteoblast adhesion, proliferation, and differentiation into mature bone-forming cells (Gomrau et al., 2005, PubMed: 15914000). This mechanism is clinically utilized in bone graft substitutes like i-Factor to enhance osseointegration and accelerate bone repair in spinal fusions and periodontal defects (FDA, P120002). While effective for localized bone regeneration, therapeutic challenges include ensuring the stability of the peptide-receptor interaction and preventing ectopic bone formation in non-target tissues.

Other names

VLA-2CD49b/CD29Collagen receptorPlatelet membrane glycoprotein Ia-IIa

Agonism of integrin receptors to mimic natural extracellular matrix interactions, triggering intracellular signaling via focal adhesion kinase (FAK) to promote osteoblast recruitment and differentiation (Bhatnagar et al., 1999, PubMed: 10403401).