title: Interleukin 12 (IL-12) induces tyrosine phosphorylation of JAK2 and TYK2: differential use of Janus family tyrosine kinases by IL-2 and IL-12.
abstract: Interleukin (IL-12) has many effects on the function of natural killer and T cells, and is important in the control of cell-mediated immunity. IL-2 and IL-12 display many similar activities, yet each also induces a distinct set of responses. A human IL-12 receptor subunit has recently been cloned and, like the IL-2R beta and IL-2R gamma, is a member of the hematopoietic receptor superfamily; however, the molecular mechanisms of IL-12 action are unknown. In this report we show that IL-12 and IL-2 induce tyrosine phosphorylation of distinct members of the Janus (JAK) family of protein tyrosine kinases in human T lymphocytes. IL-12, but not IL-2, stimulates the tyrosine phosphorylation of TYK2 and JAK2, whereas JAK1 and JAK3, which are phosphorylated in response to IL-2, are not phosphorylated after IL-12 treatment. The use of distinct but related JAK family tyrosine kinases by IL-12 and IL-2 may provide a biochemical basis for their different biological activities.
authors.affiliation: Laboratory of Experimental Immunology, National Cancer Institute-Frederick Cancer Research and Development Center, MD 21702-1201.
authors.forename: C M
authors.initials: CM
authors.lastname: Bacon
authors.forename: D W
authors.initials: DW
authors.lastname: McVicar
authors.forename: J R
authors.initials: JR
authors.lastname: Ortaldo
authors.forename: R C
authors.initials: RC
authors.lastname: Rees
authors.forename: J J
authors.initials: JJ
authors.lastname: O'Shea
authors.forename: J A
authors.initials: JA
authors.lastname: Johnston
mesh_terms: D006801:Humans; D018664:Interleukin-12 / Q000494:pharmacology*; D007376:Interleukin-2 / Q000494:pharmacology*; D053613:Janus Kinase 1; D053614:Janus Kinase 2; D053616:Janus Kinase 3; D007694:Killer Cells, Natural / Q000378:metabolism; D010766:Phosphorylation; D019000:Phosphotyrosine; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D011518:Proto-Oncogene Proteins; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000378:metabolism*; D053634:TYK2 Kinase; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D007376:Interleukin-2; D011506:Proteins; D011518:Proto-Oncogene Proteins; D018664:Interleukin-12; D019000:Phosphotyrosine; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; C507904:JAK1 protein, human; C507924:JAK2 protein, human; C507933:JAK3 protein, human; D053613:Janus Kinase 1; D053614:Janus Kinase 2; D053616:Janus Kinase 3; D053634:TYK2 Kinase; C070139:TYK2 protein, human