Abstract: The invention relates generally to the Jak family of kinases. This includes the DNA and amino acid sequences for Jak 3 kinases. Additionally, the invention concerns expression vectors comprising DNA sequences encoding a Jak 3 kinase and host cell containing such expression vectors.

Abstract: Provided are methods for regulating the cellular response to cytokines by inhibiting or enhancing of at least one Jak kinase activity which mediates the response; assays for identifying inhibitors of Jak kinase activity or cytokine-induced Jak kinase activation useful in the methods of the invention are also provided; antibodies raised against peptide fragments of at least one epitope specific for a Jak kinase without interfering with kinase activity; polypeptides for Jak kinases; and nucleic acid encoding therefor.

Abstract: Provided are methods for regulating the cellular response to cytokines by inhibiting or enhancing of at least one Jak kinase activity which mediates the response; assays for identifying inhibitors of Jak kinase activity or cytokine-induced Jak kinase activation useful in the methods of the invention are also provided; antibodies raised against peptide fragments of at least one epitope specific for a Jak kinase without interfering with kinase activity; polypeptides for Jak kinases; and nucleic acid encoding therefor.

Abstract: The invention relates generally to the Jak family of kinases. This includes the DNA and amino acid sequences for Jak 3 kinases. Additionally, the invention concerns expression vectors comprising DNA sequences encoding a Jak 3 kinase and host cell containing such expression vectors.

Abstract: The present invention is based on the discovery that a critical step in the cellular response to several cytokines is the activation (i.e. tyrosine phosphorylation) of a member of the Jak kinase family. In particular, several cytokines whose activity is mediated by the activation of Jak2 kinase are identified. The present invention provides novel methods for regulating the cellular response to these cytokines by inhibiting or enhancing the Jak kinase activity which mediates the response. Assays for identifying inhibitors of Jak kinase activity or cytokine-induced Jak kinase activation useful in the methods of the invention are also provided. Antibodies raised against peptide fragments of Jak1, Jak2, and Tyk2 kinase capable of specifically binding to these Jak kinases without interfering with kinase activity are also provided. In addition, the complete DNA coding sequence and amino acid structure of Jak2 kinase is provided by the invention.