The mouse discoidin domain receptor 1 (mDDR1) gene, localized on chromosome 1q23.3, encodes a transmembrane receptor tyrosine kinase (RTK) belonging to the discoidin domain receptor family. This receptor is characterized by an extracellular discoidin domain that mediates binding to collagens, its primary ligands. mDDR1 plays pivotal roles in regulating cell adhesion, migration, proliferation, and matrix remodeling, with critical implications in embryonic development, tissue repair, and pathological processes such as fibrosis and cancer progression. Functionally, mDDR1 signaling intersects with key pathways including the MAPK/ERK and PI3K/Akt cascades, modulating cellular responses to extracellular matrix cues. Studies using mDDR1 knockout mice have elucidated its non-redundant functions in tissue homeostasis—particularly in the kidney, mammary gland, vascular system, and nervous system—and its roles in regulating collagen ultrastructure, platelet adhesion, and neuronal axon extension.