STAT3 Is a Serine Kinase Target in T Lymphocytes

Interleukin 2 (IL-2) induces tyrosine phosphorylation of STATs 3 and 5 (signal transducer and activator of transcription). We now show that IL-2 regulation of STAT3 proteins in T cells is a complex response involving activation of two forms of STAT3: 90-kDa STAT3α and an 83-kDa carboxyl-terminal truncated STAT3β. The phosphorylation of STAT proteins on serine residues is also required for competent STAT transcription. A critical serine phosphorylation site in STAT3α is at position 727. In this study we have produced an antisera specific for STAT3α proteins phosphorylated on serine 727 and used this to monitor the phosphorylation of this residue during T lymphocyte activation. Our results show that phosphorylation of STAT3α on serine 727 is not constitutive in quiescent T cells but can be induced by the cytokine IL-2. Interestingly, triggering of the T cell antigen receptor complex or activation of protein kinase C with phorbol esters also induces phosphorylation of serine 727 but without simultaneously inducing STAT3 tyrosine phosphorylation or DNA binding. Hence, the present results show that STAT3 serine phosphorylation can be regulated independently of the tyrosine phosphorylation of this molecule. IL-2 and T cell antigen receptor complex induction of STAT3α serine 727 phosphorylation is dependent on the activity of the MEK/ERK pathway. Previous studies have identified H-7-sensitive kinase pathways that regulate STAT3 DNA binding. We show that H-7-sensitive pathways regulate STAT3 DNA binding in T cells. Nevertheless, we show that H-7-sensitive kinases do not regulate STAT3 tyrosine phosphorylation or phosphorylation of serine 727. These results thus show that STAT3 proteins are targets for multiple kinase pathways in T cells and can integrate signals from both cytokine receptors and antigen receptors.

[1]  R. Rees,et al.  Activation of STAT4 by IL-12 and IFN-alpha: evidence for the involvement of ligand-induced tyrosine and serine phosphorylation. , 1996, Journal of immunology.

[2]  M. Owen,et al.  The MAP Kinase Pathway Controls Differentiation from Double-Negative to Double-Positive Thymocyte , 1996, Cell.

[3]  J. Darnell,et al.  Transcriptionally active Stat1 is required for the antiproliferative effects of both interferon alpha and interferon gamma. , 1996, Proceedings of the National Academy of Sciences of the United States of America.

[4]  R. Perlmutter,et al.  Positive and negative selection invoke distinct signaling pathways , 1996, The Journal of experimental medicine.

[5]  J. Lammers,et al.  STAT3β, a Splice Variant of Transcription Factor STAT3, Is a Dominant Negative Regulator of Transcription* , 1996, The Journal of Biological Chemistry.

[6]  D. Cantrell,et al.  Interleukin‐2 activation of STAT5 requires the convergent action of tyrosine kinases and a serine/threonine kinase pathway distinct from the Raf1/ERK2 MAP kinase pathway. , 1996, The EMBO journal.

[7]  J. Ihle,et al.  STATs and MAPKs: obligate or opportunistic partners in signaling. , 1996, BioEssays : news and reviews in molecular, cellular and developmental biology.

[8]  Philip R. Cohen,et al.  PD 098059 Is a Specific Inhibitor of the Activation of Mitogen-activated Protein Kinase Kinase in Vitro and in Vivo(*) , 1995, The Journal of Biological Chemistry.

[9]  T. Pawson,et al.  MAP kinase phosphorylation of mSos1 promotes dissociation of mSos1-Shc and mSos1-EGF receptor complexes. , 1995, Oncogene.

[10]  L. Sanders,et al.  Cooperative transcriptional activity of Jun and Stat3 beta, a short form of Stat3. , 1995, Proceedings of the National Academy of Sciences of the United States of America.

[11]  A. Bridges,et al.  A synthetic inhibitor of the mitogen-activated protein kinase cascade. , 1995, Proceedings of the National Academy of Sciences of the United States of America.

[12]  J. Darnell,et al.  Maximal activation of transcription by statl and stat3 requires both tyrosine and serine phosphorylation , 1995, Cell.

[13]  N. Stahl,et al.  STAT3 activation by cytokines utilizing gp130 and related transducers involves a secondary modification requiring an H7-sensitive kinase. , 1995, Proceedings of the National Academy of Sciences of the United States of America.

[14]  A. Miyajima,et al.  Interleukin 2 and erythropoietin activate STAT5/MGF via distinct pathways. , 1995, The EMBO journal.

[15]  W. Paul,et al.  Cloning of murine Stat6 and human Stat6, Stat proteins that are tyrosine phosphorylated in responses to IL-4 and IL-3 but are not required for mitogenesis , 1995, Molecular and cellular biology.

[16]  L. A. Burns,et al.  Interleukin-2 triggers a novel phosphatidylinositol 3-kinase-dependent MEK activation pathway , 1995, Molecular and cellular biology.

[17]  R. Abraham,et al.  Protein-tyrosine kinase-dependent activation of STAT transcription factors in interleukin-2- or interleukin-4-stimulated T lymphocytes , 1995, The Journal of Biological Chemistry.

[18]  W. Leonard,et al.  The role of shared receptor motifs and common Stat proteins in the generation of cytokine pleiotropy and redundancy by IL-2, IL-4, IL-7, IL-13, and IL-15. , 1995, Immunity.

[19]  J. Blenis,et al.  Requirement of serine phosphorylation for formation of STAT-promoter complexes. , 1995, Science.

[20]  D. Cantrell,et al.  The regulation and function of p21ras during T-cell activation and growth. , 1995, Immunology today.

[21]  P. Heinrich,et al.  Interleukin‐6‐induced serine phosphorylation of transcription factor APRF: evidence for a role in interleukin‐6 target gene induction , 1995, FEBS letters.

[22]  A. Cherniack,et al.  Disassembly of Son-of-sevenless Proteins from Grb2 during p21 Desensitization by Insulin (*) , 1995, The Journal of Biological Chemistry.

[23]  J. Blenis,et al.  Activation of pp70/85 S6 kinases in interleukin-2-responsive lymphoid cells is mediated by phosphatidylinositol 3-kinase and inhibited by cyclic AMP , 1995, Molecular and cellular biology.

[24]  I. Kerr,et al.  Activation of JAK kinases and STAT proteins by interleukin‐2 and interferon alpha, but not the T cell antigen receptor, in human T lymphocytes. , 1994, The EMBO journal.

[25]  K. Siddle,et al.  Site-specific anti-phosphopeptide antibodies: use in assessing insulin receptor serine/threonine phosphorylation state and identification of serine-1327 as a novel site of phorbol ester-induced phosphorylation. , 1994, The Biochemical journal.

[26]  G. Drago,et al.  Discrimination between two sites of phosphorylation on adjacent amino acids by phosphorylation site-specific antibodies to phospholamban. , 1994, The Journal of biological chemistry.

[27]  S. McKnight,et al.  An interleukin-4-induced transcription factor: IL-4 Stat. , 1994, Science.

[28]  E. Liu,et al.  Involvement of the Jak-3 Janus kinase in signalling by interleukins 2 and 4 in lymphoid and myeloid cells , 1994, Nature.

[29]  J. Johnston,et al.  Phosphorylation and activation of the Jak-3 Janus kinase in response to interleukin-2 , 1994, Nature.

[30]  J. Darnell,et al.  Jak-STAT pathways and transcriptional activation in response to IFNs and other extracellular signaling proteins. , 1994, Science.

[31]  M E Greenberg,et al.  Regulation of CREB phosphorylation in the suprachiasmatic nucleus by light and a circadian clock. , 1993, Science.

[32]  M. Kennedy,et al.  Autophosphorylation of type II CaM kinase in hippocampal neurons: localization of phospho- and dephosphokinase with complementary phosphorylation site-specific antibodies. , 1993, Molecular biology of the cell.

[33]  C. Crews,et al.  Interleukin 2 stimulation of p70 S6 kinase activity is inhibited by the immunosuppressant rapamycin. , 1992, Proceedings of the National Academy of Sciences of the United States of America.

[34]  G. Crabtree,et al.  Rapamycin selectively inhibits interleukin-2 activation of p70 S6 kinase , 1992, Nature.

[35]  Takashi Uchiyama,et al.  Signal transduction by interleukin 2 in human T cells: Activation of tyrosine and ribosomal S6 kinases and cell‐cycle regulatory genes , 1992, Journal of cellular physiology.

[36]  B. Groner,et al.  Developmental and environmental regulation of a mammary gland-specific nuclear factor essential for transcription of the gene encoding beta-casein. , 1992, Proceedings of the National Academy of Sciences of the United States of America.

[37]  I. Mérida,et al.  IL-2 binding activates a tyrosine-phosphorylated phosphatidylinositol-3-kinase. , 1991, Journal of immunology.

[38]  R. Abraham,et al.  Interleukin 2- and polyomavirus middle T antigen-induced modification of phosphatidylinositol 3-kinase activity in activated T lymphocytes , 1991, Molecular and cellular biology.

[39]  L. Cantley,et al.  Interleukin-2 receptor regulates activation of phosphatidylinositol 3-kinase. , 1991, The Journal of biological chemistry.

[40]  R. Perlmutter,et al.  Interaction of the IL-2 receptor with the src-family kinase p56lck: identification of novel intermolecular association , 1991, Science.

[41]  K. Dobashi,et al.  Interleukin 2 induces tyrosine phosphorylation and activation of p72-74 Raf-1 kinase in a T-cell line. , 1991, Proceedings of the National Academy of Sciences of the United States of America.

[42]  P. Greengard,et al.  Production of phosphorylation state-specific antibodies. , 1991, Methods in enzymology.

[43]  Kendall A. Smith,et al.  Interleukin-2: inception, impact, and implications. , 1988, Science.

[44]  H. Ohno,et al.  Establishment of an interleukin 2-dependent human T cell line from a patient with T cell chronic lymphocytic leukemia who is not infected with human T cell leukemia/lymphoma virus. , 1987, Blood.