Discoidin domain receptor-2 (DDR2) is a cell surface tyrosine kinase receptor that can be activated by soluble collagen and has been implicated in diverse physiological functions including organism growth and wound repair. DDR2 binds to and is activated by collagen I, II, III, V, and X, with the notable exception of basement membrane collagen IV. DDR2 is expressed in connective tissues arising from embryonic mesoderm. DDR2 regulates cell proliferation, cell adhesion, migration, and extracellular matrix remodeling.