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For other uses, see Lyn (disambiguation).
LYN proto-oncogene, Src family tyrosine kinase
PDB 1wa7 EBI.png
PDB rendering based on 1wa7.
Available structures
PDB Ortholog search: PDBe, RCSB
Symbols LYN ; JTK8; p53Lyn; p56Lyn
External IDs OMIM165120 MGI96892 HomoloGene55649 ChEMBL: 3905 GeneCards: LYN Gene
EC number
Species Human Mouse
Entrez 4067 17096
Ensembl ENSG00000254087 ENSMUSG00000042228
UniProt P07948 P25911
RefSeq (mRNA) NM_001111097 NM_001111096
RefSeq (protein) NP_001104567 NP_001104566
Location (UCSC) Chr 8:
56.79 – 56.92 Mb
Chr 4:
3.68 – 3.81 Mb
PubMed search [1] [2]

Tyrosine-protein kinase Lyn is a protein that in humans is encoded in humans by the LYN gene.[1]

Lyn is a member of the Src family of protein tyrosine kinases, which is mainly expressed in hematopoietic cells,[2] in neural tissues[3] liver, and adipose tissue.[4] In various hematopoietic cells, Lyn has emerged as a key enzyme involved in the regulation of cell activation. In these cells, a small amount of LYN is associated with cell surface receptor proteins, including the B cell antigen receptor (BCR),[5][6] CD40,[7] or CD19.[8] The abbreviation Lyn is derived from Lck/Yes novel tyrosine kinase, Lck and Yes also being members of the Src kinase family.


Lyn has been described to have an inhibitory role in myeloid lineage proliferation.[9] Following engagement of the B cell receptors, Lyn undergoes rapid phosphorylation and activation. LYN activation triggers a cascade of signaling events mediated by Lyn phosphorylation of tyrosine residues within the immunoreceptor tyrosine-based activation motifs (ITAM) of the receptor proteins, and subsequent recruitment and activation of other kinases including Syk, phosholipase Cγ2 (PLCγ2) and phosphatidyl inositol-3 kinase.[8][10] These kinases provide activation signals, which play critical roles in proliferation, Ca2+ mobilization and cell differentiation. Lyn plays an essential role in the transmission of inhibitory signals through phosphorylation of tyrosine residues within the immunoreceptor tyrosine-based inhibitory motifs (ITIM) in regulatory proteins such as CD22, PIR-B and FCγRIIb1. Their ITIM phosphorylation subsequently leads to recruitment and activation of phosphatases such as SHIP-1 and SHP-1,[11][12][13][14][15] which further downmodulate signaling pathways, attenuate cell activation and can mediate tolerance. In B cells, Lyn sets the threshold of cell signaling and maintains the balance between activation and inhibition. Lyn thus functions as a rheostat that modulates signaling rather than as a binary on-off switch.[16][17][18]

Lyn has also been implicated to have a role in the insulin signaling pathway. Activated Lyn phosphorylates insulin receptor substrate 1 (IRS1). This phosphorylation of IRS1 leads to an increase in translocation of Glut-4 to the cell membrane and increased glucose utilization.[19] In turn, activation of the insulin receptor has been shown to increase autophosphorylation of Lyn suggesting a possible feedback loop.[20] The insulin secretagogue, glimepiride (Amaryl®) activates Lyn in adipocytes via the disruption of lipid rafts.[21] This indirect Lyn activation may modulate the extrapancreatic glycemic control activity of glimepiride.[21][22]


Much of the current knowledge about Lyn has emerged from studies of genetically manipulated mice. Lyn deficient mice display a phenotype that includes splenomegaly, a dramatic increase in numbers of myeloid progenitors and monocyte/macrophage tumors. Biochemical analysis of cells from these mutants revealed that Lyn is essential in establishing ITIM-dependent inhibitory signaling and for activation of specific protein tyrosine phosphatases within myeloid cells.[9]

Mice that expressed a hyperactive Lyn allele were tumor free and displayed no propensity toward hematological malignancy. These mice have reduced numbers of conventional B lymphocytes, down-regulated surface immunoglobulin M and costimulatory molecules, and elevated numbers of B1a B cells. With age these animals developed a glomerulonephritis phenotype associated with a 30% reduction in life expectancy.[23]


LYN has been shown to interact with:

See also[edit]


  1. ^ Yamanashi Y, Fukushige S, Semba K, Sukegawa J, Miyajima N, Matsubara K, Yamamoto T, Toyoshima K (January 1987). "The yes-related cellular gene lyn encodes a possible tyrosine kinase similar to p56lck". Mol. Cell. Biol. 7 (1): 237–43. PMC 365062. PMID 3561390. 
  2. ^ Yamanashi Y, Mori S, Yoshida M, et al. (September 1989). "Selective expression of a protein-tyrosine kinase, p56lyn, in hematopoietic cells and association with production of human T-cell lymphotropic virus type I". Proc. Natl. Acad. Sci. U.S.A. 86 (17): 6538–42. doi:10.1073/pnas.86.17.6538. PMC 297879. PMID 2505253. 
  3. ^ Umemori H, Wanaka A, Kato H, Takeuchi M, Tohyama M, Yamamoto T (December 1992). "Specific expressions of Fyn and Lyn, lymphocyte antigen receptor-associated tyrosine kinases, in the central nervous system". Brain Res. Mol. Brain Res. 16 (3–4): 303–10. doi:10.1016/0169-328X(92)90239-8. PMID 1337939. 
  4. ^ Yamada E, Pessin J, Kurland I, Schwartz G, Bastie C (February 2010). "Fyn-dependent regulation of energy expediture and body weight is mediated by tyrosine phosphorylation of LKB1". Cell Metab. 11 (2): 113–124. doi:10.1016/j.cmet.2009.12.010. PMC 2830006. PMID 20142099. 
  5. ^ Yamamoto T, Yamanashi Y, Toyoshima K (April 1993). "Association of Src-family kinase Lyn with B-cell antigen receptor". Immunol. Rev. 132: 187–206. doi:10.1111/j.1600-065X.1993.tb00843.x. PMID 8349296. 
  6. ^ Campbell MA, Sefton BM (May 1992). "Association between B-lymphocyte membrane immunoglobulin and multiple members of the Src family of protein tyrosine kinases". Mol. Cell. Biol. 12 (5): 2315–21. PMC 364403. PMID 1569953. 
  7. ^ Ren CL, Morio T, Fu SM, Geha RS (February 1994). "Signal transduction via CD40 involves activation of lyn kinase and phosphatidylinositol-3-kinase, and phosphorylation of phospholipase C gamma 2". J. Exp. Med. 179 (2): 673–80. doi:10.1084/jem.179.2.673. PMC 2191357. PMID 7507510. 
  8. ^ a b Campbell 1999
  9. ^ a b Harder K, Parsons L, Ames J, Evans N, Kountouri N, Clark R, Quillici C, Grail D, Hodgson G, Dunn A, Hibbs M (October 2001). "Gain – and loss-of-function lyn mutant mice define a critical inhibitory role of lyn in the myeloid lineage". Immunity. 15 (4): 603–615. doi:10.1016/S1074-7613(01)00208-4. PMID 11672542. 
  10. ^ Yamanashi Y, Fukui Y, Wongsasant B, et al. (February 1992). "Activation of Src-like protein-tyrosine kinase Lyn and its association with phosphatidylinositol 3-kinase upon B-cell antigen receptor-mediated signaling". Proc. Natl. Acad. Sci. U.S.A. 89 (3): 1118–22. doi:10.1073/pnas.89.3.1118. PMC 48397. PMID 1371009. 
  11. ^ Cornall RJ, Cyster JG, Hibbs ML, et al. (April 1998). "Polygenic autoimmune traits: Lyn, CD22, and SHP-1 are limiting elements of a biochemical pathway regulating BCR signaling and selection". Immunity 8 (4): 497–508. doi:10.1016/S1074-7613(00)80554-3. PMID 9586639. 
  12. ^ Smith KG, Tarlinton DM, Doody GM, Hibbs ML, Fearon DT (March 1998). "Inhibition of the B cell by CD22: a requirement for Lyn". J. Exp. Med. 187 (5): 807–11. doi:10.1084/jem.187.5.807. PMC 2212179. PMID 9480991. 
  13. ^ Chan VW, Lowell CA, DeFranco AL (May 1998). "Defective negative regulation of antigen receptor signaling in Lyn-deficient B lymphocytes". Curr. Biol. 8 (10): 545–53. doi:10.1016/S0960-9822(98)70223-4. PMID 9601638. 
  14. ^ Nishizumi H, Horikawa K, Mlinaric-Rascan I, Yamamoto T (April 1998). "A double-edged kinase Lyn: a positive and negative regulator for antigen receptor-mediated signals". J. Exp. Med. 187 (8): 1343–8. doi:10.1084/jem.187.8.1343. PMC 2212230. PMID 9547345. 
  15. ^ Maeda A, Scharenberg AM, Tsukada S, Bolen JB, Kinet JP, Kurosaki T (April 1999). "Paired immunoglobulin-like receptor B (PIR-B) inhibits BCR-induced activation of Syk and Btk by SHP-1". Oncogene 18 (14): 2291–7. doi:10.1038/sj.onc.1202552. PMID 10327049. 
  16. ^ Lowell CA (July 2004). "Src-family kinases: rheostats of immune cell signaling". Mol. Immunol. 41 (6–7): 631–43. doi:10.1016/j.molimm.2004.04.010. PMID 15220000. 
  17. ^ Saijo K, Schmedt C, Su IH, et al. (March 2003). "Essential role of Src-family protein tyrosine kinases in NF-kappaB activation during B cell development". Nat. Immunol. 4 (3): 274–9. doi:10.1038/ni893. PMID 12563261. 
  18. ^ Xu Y, Harder KW, Huntington ND, Hibbs ML, Tarlinton DM (January 2005). "Lyn tyrosine kinase: accentuating the positive and the negative". Immunity 22 (1): 9–18. doi:10.1016/j.immuni.2004.12.004. PMID 15664155. 
  19. ^ Müller G, Wied S, Frick W (July 2000). "Cross talk of pp125(FAK) and pp59(Lyn) non-receptor tyrosine kinases to insulin-mimetic signaling in adipocytes". Mol. Cell. Biol. 20 (13): 4708–4723. doi:10.1128/mcb.20.13.4708-4723.2000. PMC 85892. PMID 10848597. 
  20. ^ Anderwald C, Muller G, Koca G, Furnsinn C, Waldhausl W, Roden M (2002). "Short-term lpetin-dependent inhibition of hepatic gluconeogenesis is mediated by insulin receptor substrate-2". Mol. Endocrinol. 16 (7): 1612–1628. doi:10.1210/me.16.7.1612. PMID 12089355. 
  21. ^ a b Müller, G (2000). "The molecular mechanism of the insulin-mimetic sensitizing activity of the antidiabetic sulfonylurea drug Amaryl". Mol. Med. 6 (11): 907–933. PMC 1949923. PMID 11147570. 
  22. ^ Müller G, Schulz A, Wied S, Frick W (2005). "Regulation of lipid raft proteins by glimepiride- and insulin-induced glycosylphospatidylinositol-specific phospholipase C in rat adipocytes". Biochem. Pharmacol. 69: 761–780. doi:10.1016/j.bcp.2004.11.014. PMID 15710354. 
  23. ^ Hibbs ML, Harder KW, Armes J, et al. (December 2002). "Sustained activation of Lyn tyrosine kinase in vivo leads to autoimmunity". J. Exp. Med. 196 (12): 1593–604. doi:10.1084/jem.20020515. PMC 2196073. PMID 12486102. 
  24. ^ a b Manié SN, Beck AR, Astier A, Law SF, Canty T, Hirai H, Druker BJ, Avraham H, Haghayeghi N, Sattler M, Salgia R, Griffin JD, Golemis EA, Freedman AS (February 1997). "Involvement of p130(Cas) and p105(HEF1), a novel Cas-like docking protein, in a cytoskeleton-dependent signaling pathway initiated by ligation of integrin or antigen receptor on human B cells". J. Biol. Chem. 272 (7): 4230–6. doi:10.1074/jbc.272.7.4230. PMID 9020138. 
  25. ^ Qiu W, Cobb RR, Scholz W (May 1998). "Inhibition of p130cas tyrosine phosphorylation by calyculin A". J. Leukoc. Biol. 63 (5): 631–5. PMID 9581808. 
  26. ^ a b Liang X, Wisniewski D, Strife A, Clarkson B, Resh MD (April 2002). "Phosphatidylinositol 3-kinase and Src family kinases are required for phosphorylation and membrane recruitment of Dok-1 in c-Kit signaling". J. Biol. Chem. 277 (16): 13732–8. doi:10.1074/jbc.M200277200. PMID 11825908. 
  27. ^ Linnekin D, DeBerry CS, Mou S (October 1997). "Lyn associates with the juxtamembrane region of c-Kit and is activated by stem cell factor in hematopoietic cell lines and normal progenitor cells". J. Biol. Chem. 272 (43): 27450–5. doi:10.1074/jbc.272.43.27450. PMID 9341198. 
  28. ^ Poe JC, Fujimoto M, Jansen PJ, Miller AS, Tedder TF (June 2000). "CD22 forms a quaternary complex with SHIP, Grb2, and Shc. A pathway for regulation of B lymphocyte antigen receptor-induced calcium flux". J. Biol. Chem. 275 (23): 17420–7. doi:10.1074/jbc.M001892200. PMID 10748054. 
  29. ^ Greer SF, Justement LB (May 1999). "CD45 regulates tyrosine phosphorylation of CD22 and its association with the protein tyrosine phosphatase SHP-1". J. Immunol. 162 (9): 5278–86. PMID 10228003. 
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  31. ^ Pathan NI, Geahlen RL, Harrison ML (November 1996). "The protein-tyrosine kinase Lck associates with and is phosphorylated by Cdc2". J. Biol. Chem. 271 (44): 27517–23. doi:10.1074/jbc.271.44.27517. PMID 8910336. 
  32. ^ van Dijk TB, van Den Akker E, Amelsvoort MP, Mano H, Löwenberg B, von Lindern M (November 2000). "Stem cell factor induces phosphatidylinositol 3'-kinase-dependent Lyn/Tec/Dok-1 complex formation in hematopoietic cells". Blood 96 (10): 3406–13. PMID 11071635. 
  33. ^ Chin H, Arai A, Wakao H, Kamiyama R, Miyasaka N, Miura O (May 1998). "Lyn physically associates with the erythropoietin receptor and may play a role in activation of the Stat5 pathway". Blood 91 (10): 3734–45. PMID 9573010. 
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  35. ^ Baran CP, Tridandapani S, Helgason CD, Humphries RK, Krystal G, Marsh CB (October 2003). "The inositol 5'-phosphatase SHIP-1 and the Src kinase Lyn negatively regulate macrophage colony-stimulating factor-induced Akt activity". J. Biol. Chem. 278 (40): 38628–36. doi:10.1074/jbc.M305021200. PMID 12882960. 
  36. ^ Müller G, Wied S, Frick W (July 2000). "Cross talk of pp125(FAK) and pp59(Lyn) non-receptor tyrosine kinases to insulin-mimetic signaling in adipocytes". Mol. Cell. Biol. 20 (13): 4708–23. doi:10.1128/mcb.20.13.4708-4723.2000. PMC 85892. PMID 10848597. 
  37. ^ Gross BS, Lee JR, Clements JL, Turner M, Tybulewicz VL, Findell PR, Koretzky GA, Watson SP (February 1999). "Tyrosine phosphorylation of SLP-76 is downstream of Syk following stimulation of the collagen receptor in platelets". J. Biol. Chem. 274 (9): 5963–71. doi:10.1074/jbc.274.9.5963. PMID 10026222. 
  38. ^ Durum SK, Aiello FB (2003). "Interleukin-7 induces MUC1". Cancer Biol. Ther. 2 (2): 194–5. doi:10.4161/cbt.2.2.351. PMID 12750562. 
  39. ^ Pleiman CM, Clark MR, Gauen LK, Winitz S, Coggeshall KM, Johnson GL, Shaw AS, Cambier JC (September 1993). "Mapping of sites on the Src family protein tyrosine kinases p55blk, p59fyn, and p56lyn which interact with the effector molecules phospholipase C-gamma 2, microtubule-associated protein kinase, GTPase-activating protein, and phosphatidylinositol 3-kinase". Mol. Cell. Biol. 13 (9): 5877–87. PMC 360336. PMID 8395016. 
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  41. ^ Grishin AV, Azhipa O, Semenov I, Corey SJ (August 2001). "Interaction between growth arrest-DNA damage protein 34 and Src kinase Lyn negatively regulates genotoxic apoptosis". Proc. Natl. Acad. Sci. U.S.A. 98 (18): 10172–7. doi:10.1073/pnas.191130798. PMC 56934. PMID 11517336. 
  42. ^ Brown VK, Ogle EW, Burkhardt AL, Rowley RB, Bolen JB, Justement LB (June 1994). "Multiple components of the B cell antigen receptor complex associate with the protein tyrosine phosphatase, CD45". J. Biol. Chem. 269 (25): 17238–44. PMID 7516335. 
  43. ^ Sidorenko SP, Law CL, Chandran KA, Clark EA (January 1995). "Human spleen tyrosine kinase p72Syk associates with the Src-family kinase p53/56Lyn and a 120-kDa phosphoprotein". Proc. Natl. Acad. Sci. U.S.A. 92 (2): 359–63. doi:10.1073/pnas.92.2.359. PMC 42739. PMID 7831290. 
  44. ^ Xu H, Zhao H, Tian W, Yoshida K, Roullet JB, Cohen DM (March 2003). "Regulation of a transient receptor potential (TRP) channel by tyrosine phosphorylation. SRC family kinase-dependent tyrosine phosphorylation of TRPV4 on TYR-253 mediates its response to hypotonic stress". J. Biol. Chem. 278 (13): 11520–7. doi:10.1074/jbc.M211061200. PMID 12538589. 
  45. ^ Cen O, Gorska MM, Stafford SJ, Sur S, Alam R (March 2003). "Identification of UNC119 as a novel activator of SRC-type tyrosine kinases". J. Biol. Chem. 278 (10): 8837–45. doi:10.1074/jbc.M208261200. PMID 12496276. 

Further reading[edit]