DDR1 (Epithelial discoidin domain-containing receptor 1, CD167a) is a receptor tyrosine kinase involved in cell-cell interactions and recognition. It is e, Xenopus/Amphibian,pressed in epithelial cells especially in the kidney, lung, gastrointestinal tract, and brain, and more highly in human breast, ovarian, esophageal, and pediatric brain tumors. Types I-VI collagen all induce the autophosphorylation of DDR1. Collagen regulates the interaction of DDR1 with KIBRA (WWC1), activating MAPK; these events are involved in mammary gland development.