Ivashkiv L B
Department of Medicine, Hospital for Special Surgery, Weill Medical College of Cornell University, New York 10021, USA.
Rev Immunogenet. 2000;2(2):220-30.
Many, if not most, cytokines important for immune responses utilize the Jak-STAT signaling pathway. Jaks are receptor-associated protein tyrosine kinases, and STATs are latent cytoplasmic transcription factors that are activated by tyrosine phosphorylation. STATs play critical, nonredundant roles in mediating cellular transcriptional responses to cytokines, and in cell activation, survival and proliferation. The roles of Jaks and STATs in immune responses have been elucidated by analysis of induction of STAT target genes, and of mice rendered deficient in Jak and STAT genes. Cytokine signaling is modulated by crosstalk between the Jak-STAT pathway and pathways triggered by other major immune receptors, such as antigen receptors and receptors for inflammatory cytokines. Tight regulation of cytokine signaling is required for homeostasis, and several constitutive and inducible mechanisms for downregulation of Jak-STAT signaling have been described.
许多（即便不是大多数）对免疫反应至关重要的细胞因子都利用Jak-STAT信号通路。Jak是与受体相关的蛋白酪氨酸激酶，而STAT是潜在的细胞质转录因子，通过酪氨酸磷酸化被激活。STAT在介导细胞对细胞因子的转录反应以及细胞激活、存活和增殖中发挥关键的、非冗余的作用。通过分析STAT靶基因的诱导情况以及对Jak和STAT基因缺陷的小鼠的研究，已阐明Jak和STAT在免疫反应中的作用。细胞因子信号传导通过Jak-STAT通路与其他主要免疫受体（如抗原受体和炎性细胞因子受体）触发的通路之间的相互作用而受到调节。细胞因子信号传导的严格调控对于体内平衡是必需的，并且已经描述了几种组成型和诱导型下调Jak-STAT信号传导的机制。
