RGD

RGD is the Arginine-Glycine-Aspartic acid sequence, a short peptide motif that functions as a key cell adhesion site in many extracellular matrix proteins. The RGD sequence is recognized by several integrin receptors on the surface of animal cells, enabling attachment to the surrounding matrix and triggering signals that influence cell spreading, migration, proliferation, and survival. The motif was identified in the 1980s as a minimal integrin-binding sequence within fibronectin, vitronectin, and other ECM proteins, and remains a foundational concept in studies of cell–matrix interactions.

Natural occurrence and function

RGD-containing regions are present in multiple ECM proteins, contributing to cell adhesion in diverse tissues. Binding to integrins such as αvβ3, αvβ5, and α5β1 mediates adhesive contacts, influences cytoskeletal organization, and can activate intracellular signaling pathways that regulate behavior such as differentiation and migration. The interaction can be modulated by the surrounding protein context and by conformational changes in the ECM.

Applications and uses

In biomaterials and tissue engineering, RGD sequences are used to functionalize surfaces and scaffolds to promote cell attachment and integration with implanted materials. Peptides may be used in linear or cyclic forms; cyclic RGD variants often show higher affinity and specificity for certain integrins. RGD motifs are exploited in drug delivery and molecular imaging to target integrin-expressing cells, including tumor cells and endothelial cells involved in angiogenesis. Research on RGD also informs the development of anti-adhesive or anti-angiogenic therapies by interfering with integrin–ligand interactions.

Other uses

In biology and medicine, RGD typically refers to this adhesion motif. The term can occur in broader discussions of cell adhesion, ECM biology, and integrin signaling.