LYN a non-receptor tyrosine-protein kinase of the Src family that transmits signals from cell surface receptors and plays an important role in the regulation of innate and adaptive immune responses, hematopoiesis, responses to growth factors and cytokines, and integrin signaling in B cells, hematopoietic progenitors, platelets, erythrocytes, and in mature myeloid cells, such as dendritic cells, neutrophils and eosinophils. Functions primarily as negative regulator, but can also function as activator, depending on the context. Required for the initiation of the B-cell response, but also for its down-regulation and termination. Plays an important role in the regulation of B-cell differentiation, proliferation, survival and apoptosis, and is important for immune self-tolerance. Acts downstream of several immune receptors, including the B-cell receptor, CD79A, CD79B, CD5, CD19, CD22, CSF2, CXCR4, EPOR, FCER1, FCGR2, FCGR1A, IL3, IL5, TLR2 and TLR4. Acts downstream of KIT, MPL. Regulates cell proliferation, survival, differentiation, migration, adhesion, degranulation, and cytokine release. Down-regulates signaling pathways by phosphorylation of immunoreceptor tyrosine-based inhibitory motifs (ITIM), that then serve as binding sites for phosphatases that modulate signaling. Belongs to the protein kinase superfamily. Tyr protein kinase family. SRC subfamily. Detected in monocytes. placenta, fetal brain, lung, liver and kidney. Widely expressed in a variety of organs, tissues, and cell types such as epidermoid, hematopoietic, and neuronal cells. Expressed in primary neuroblastoma tumors. 2 alternatively spliced human isoforms have been reported. Note: This description may include information from UniProtKB.
Protein type: EC; Kinase, protein; Oncoprotein; Protein kinase, TK; Protein kinase, tyrosine (non-receptor); Src family; TK group
Chromosomal Location of Human Ortholog: 5q12
Cellular Component:  cell-cell adherens junction; cytoplasm; extrinsic component of cytoplasmic side of plasma membrane; glutamatergic synapse; Golgi apparatus; integrin alpha2-beta1 complex; intracellular membrane-bounded organelle; mast cell granule; membrane; membrane raft; mitochondrial crista; mitochondrial intermembrane space; mitochondrial membrane; nucleus; perinuclear region of cytoplasm; plasma membrane; postsynaptic density; postsynaptic specialization, intracellular component
Molecular Function:  ATP binding; enzyme binding; ephrin receptor binding; gamma-tubulin binding; glycosphingolipid binding; integrin binding; ion channel binding; kinase activity; non-membrane spanning protein tyrosine kinase activity; phosphoprotein binding; phosphorylation-dependent protein binding; platelet-derived growth factor receptor binding; protein binding; protein kinase activity; protein tyrosine kinase activity; protein-containing complex binding; SH3 domain binding; signaling receptor binding; ubiquitin protein ligase binding
Biological Process:  adaptive immune response; B cell homeostasis; B cell receptor signaling pathway; cell differentiation; cellular response to DNA damage stimulus; cellular response to extracellular stimulus; cellular response to heat; cellular response to retinoic acid; cytokine secretion; dendritic cell differentiation; erythrocyte differentiation; Fc receptor mediated inhibitory signaling pathway; Fc receptor mediated stimulatory signaling pathway; hemopoiesis; histamine secretion by mast cell; immune response-regulating cell surface receptor signaling pathway; innate immune response; intracellular signal transduction; lipopolysaccharide-mediated signaling pathway; negative regulation of B cell proliferation; negative regulation of cell proliferation; negative regulation of ERK1 and ERK2 cascade; negative regulation of intracellular signal transduction; negative regulation of MAP kinase activity; negative regulation of mast cell proliferation; negative regulation of myeloid leukocyte differentiation; negative regulation of protein phosphorylation; negative regulation of toll-like receptor 2 signaling pathway; negative regulation of toll-like receptor 4 signaling pathway; neuron projection development; oligodendrocyte development; peptidyl-tyrosine autophosphorylation; peptidyl-tyrosine phosphorylation; platelet degranulation; positive regulation of aspartic-type endopeptidase activity involved in amyloid precursor protein catabolic process; positive regulation of cell migration; positive regulation of cell proliferation; positive regulation of cellular component movement; positive regulation of dendritic cell apoptotic process; positive regulation of Fc receptor mediated stimulatory signaling pathway; positive regulation of glial cell proliferation; positive regulation of mast cell proliferation; positive regulation of neuron projection development; positive regulation of oligodendrocyte progenitor proliferation; positive regulation of phosphatidylinositol 3-kinase activity; positive regulation of phosphorylation; positive regulation of protein phosphorylation; positive regulation of stress-activated protein kinase signaling cascade; positive regulation of tyrosine phosphorylation of STAT protein; protein autophosphorylation; protein phosphorylation; regulation of B cell apoptotic process; regulation of B cell receptor signaling pathway; regulation of cell adhesion mediated by integrin; regulation of cytokine production; regulation of cytokine secretion; regulation of ERK1 and ERK2 cascade; regulation of erythrocyte differentiation; regulation of inflammatory response; regulation of mast cell activation; regulation of mast cell degranulation; regulation of monocyte chemotaxis; regulation of platelet aggregation; regulation of release of sequestered calcium ion into cytosol; response to amino acid; response to axon injury; response to carbohydrate; response to drug; response to hormone; response to insulin; response to organic cyclic compound; response to peptide hormone; response to sterol depletion; response to toxic substance; tolerance induction to self antigen; transmembrane receptor protein tyrosine kinase signaling pathway
Reference #:  Q07014 (UniProtKB)
Alt. Names/Synonyms: Lyn; lyn protein non-receptor kinase; Tyrosine-protein kinase Lyn; v-yes-1 Yamaguchi sarcoma viral related oncogene homolog; Yamaguchi sarcoma viral (v-yes-1) oncogene homolog
Gene Symbols: Lyn
Molecular weight: 58,660 Da
Basal Isoelectric point: 6.7  Predict pI for various phosphorylation states
CST Pathways:  B Cell Receptor Signaling  |  GPCR Signaling to MAPKs  |  PI3K/Akt Signaling  |  Tyrosine Kinases & Substrates
Protein-Specific Antibodies or siRNAs from Cell Signaling Technology® Total Proteins
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Cross-references to other databases:  STRING  |  Reactome  |  BioGPS  |  Pfam  |  ENZYME  |  Phospho.ELM  |  NetworKIN  |  UniProtKB  |  Entrez-Gene  |  Ensembl Gene