Tyrosine kinase that functions as cell surface receptor for fibrillar collagen and regulates cell attachment to the extracellular matrix, remodeling of the extracellular matrix, cell migration, differentiation, survival and cell proliferation. Collagen binding triggers a signaling pathway that involves SRC and leads to the activation of MAP kinases. Regulates remodeling of the extracellular matrix by up-regulation of the matrix metalloproteinases MMP2, MMP7 and MMP9, and thereby facilitates cell migration and wound healing, but also tumor cell invasion. Promotes smooth muscle cell migration, and thereby contributes to arterial wound healing. Phosphorylates PTPN11 (By similarity). Required for normal blastocyst implantation during pregnancy, for normal mammary gland differentiation and normal lactation. Required for normal ear morphology and normal hearing. ATP + L-tyrosyl-[protein] = ADP + H(+) + O-phospho-L-tyrosyl-[protein] Homodimer. Interacts (via PPxY motif) with WWC1 (via WW domains) in a collagen-regulated manner. Forms a tripartite complex with WWC1 and PRKCZ, but predominantly in the absence of collagen. Interacts (tyrosine phosphorylated) with SHC1. Interacts with SRC. Interacts with MYH9. Interacts with CDH1. Interacts with PTPN11. Interacts with NCK2 (By similarity). Detected in the cochlea and the organ of Corti in the inner ear. Isoform 1 is predominant and is expressed in developing embryo and adult brain. Isoform 2 is expressed in various epithelial cells. Autophosphorylated in response to fibrillar collagen binding. Mice are born at the expected Mendelian rate, but female mice are dwarfs and most of them are unable to bear offspring, due to defects in blastocyte implantation in the uterus. About one fifth can bear offspring, but for these the mammary gland fails to undergo proper differentiation during pregnancy, with hyperproliferation and abnormal branching of the mammary ducts, leading to a lactation defect. In addition, mice exhibit hearing loss, due to alterations of the inner ear. Mice display poor calcification of the fibula. They also exhibit defects in the structure of the slit diaphragm in kidney glomeruli, leading to proteinuria, but do not show overt signs of kidney dysfunction. Belongs to the protein kinase superfamily. Tyr protein kinase family. Insulin receptor subfamily.