Non-receptor tyrosine-protein kinase that plays a role in many biological processes including regulation of cell growth and survival, cell adhesion, integrin-mediated signaling, cytoskeletal remodeling, cell motility, immune response and axon guidance. Inactive FYN is phosphorylated on its C-terminal tail within the catalytic domain. Following activation by PKA, the protein subsequently associates with PTK2/FAK1, allowing PTK2/FAK1 phosphorylation, activation and targeting to focal adhesions. Involved in the regulation of cell adhesion and motility through phosphorylation of CTNNB1 (beta-catenin) and CTNND1 (delta-catenin). Regulates cytoskeletal remodeling by phosphorylating several proteins including the actin regulator WAS and the microtubule-associated proteins MAP2 and MAPT. Promotes cell survival by phosphorylating AGAP2/PIKE-A and preventing its apoptotic cleavage. Participates in signal transduction pathways that regulate the integrity of the glomerular slit diaphragm (an essential part of the glomerular filter of the kidney) by phosphorylating several slit diaphragm components including NPHS1, KIRREL1 and TRPC6. Plays a role in neural processes by phosphorylating DPYSL2, a multifunctional adapter protein within the central nervous system, ARHGAP32, a regulator for Rho family GTPases implicated in various neural functions, and SNCA, a small pre-synaptic protein. Participates in the downstream signaling pathways that lead to T-cell differentiation and proliferation following T-cell receptor (TCR) stimulation. Phosphorylates PTK2B/PYK2 in response to T-cell receptor activation. Also participates in negative feedback regulation of TCR signaling through phosphorylation of PAG1, thereby promoting interaction between PAG1 and CSK and recruitment of CSK to lipid rafts. CSK maintains LCK and FYN in an inactive form. Promotes CD28-induced phosphorylation of VAV1. Belongs to the protein kinase superfamily. Tyr protein kinase family. SRC subfamily. Isoform 1 is highly expressed in the brain. Isoform 2 is expressed in cells of hemopoietic lineages, especially T-lymphocytes. 3 alternatively spliced human isoforms have been reported. Note: This description may include information from UniProtKB.
Protein type: EC 126.96.36.199; Kinase, protein; Oncoprotein; Protein kinase, TK; Protein kinase, tyrosine (non-receptor); Src family; TK group
Molecular Function: alpha-tubulin binding; ATP binding; CD4 receptor binding; CD8 receptor binding; disordered domain specific binding; enzyme binding; ephrin receptor binding; growth factor receptor binding; identical protein binding; ion channel binding; metal ion binding; non-membrane spanning protein tyrosine kinase activity; peptide hormone receptor binding; phosphatidylinositol 3-kinase binding; protein binding; protein tyrosine kinase activity; T cell receptor binding; tau protein binding; tau-protein kinase activity; type 5 metabotropic glutamate receptor binding
Biological Process: activated T cell proliferation; adaptive immune response; axon guidance; blood coagulation; calcium ion transport; cellular response to amyloid-beta; cellular response to glycine; cellular response to L-glutamate; cellular response to peptide hormone stimulus; cellular response to platelet-derived growth factor stimulus; cellular response to transforming growth factor beta stimulus; cytokine-mediated signaling pathway; dendrite morphogenesis; dendritic spine maintenance; detection of mechanical stimulus involved in sensory perception of pain; ephrin receptor signaling pathway; Fc-gamma receptor signaling pathway involved in phagocytosis; feeding behavior; forebrain development; heart process; intracellular signal transduction; learning; leukocyte migration; MAPK cascade; modulation of chemical synaptic transmission; negative regulation of dendritic spine maintenance; negative regulation of extrinsic apoptotic signaling pathway in absence of ligand; negative regulation of gene expression; negative regulation of hydrogen peroxide biosynthetic process; negative regulation of neuron apoptotic process; negative regulation of oxidative stress-induced cell death; negative regulation of protein catabolic process; negative regulation of protein ubiquitination; neuron migration; peptidyl-tyrosine phosphorylation; platelet activation; positive regulation of cysteine-type endopeptidase activity; positive regulation of I-kappaB kinase/NF-kappaB signaling; positive regulation of neuron death; positive regulation of neuron projection development; positive regulation of non-membrane spanning protein tyrosine kinase activity; positive regulation of phosphatidylinositol 3-kinase signaling; positive regulation of protein kinase B signaling; positive regulation of protein localization to membrane; positive regulation of protein localization to nucleus; positive regulation of protein targeting to membrane; positive regulation of tyrosine phosphorylation of STAT protein; protein phosphorylation; regulation of calcium ion import across plasma membrane; regulation of cell shape; regulation of defense response to virus by virus; regulation of glutamate receptor signaling pathway; regulation of peptidyl-tyrosine phosphorylation; response to amyloid-beta; response to ethanol; response to hydrogen peroxide; response to singlet oxygen; stimulatory C-type lectin receptor signaling pathway; T cell costimulation; T cell receptor signaling pathway; vascular endothelial growth factor receptor signaling pathway