Kim T K, Maniatis T
Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
Science. 1996 Sep 20;273(5282):1717-9. doi: 10.1126/science.273.5282.1717.
STAT proteins (signal transducers and activators of transcription) are latent cytoplasmic transcription factors that are phosphorylated by Janus kinases in response to cytokines. Phosphorylated STAT proteins translocate to the nucleus, where they transiently turn on specific sets of cytokine-inducible genes. The mechanism that controls the amounts of activated STAT proteins is not understood. STAT1 proteins activated by interferon-gamma treatment in HeLa cells were shown to be stabilized by a proteasome inhibitor and ubiquitinated in vivo. Thus, the amount of activated STAT1 may be negatively regulated by the ubiquitin-proteasome pathway.
信号转导子和转录激活子（STAT）蛋白是潜在的细胞质转录因子，在细胞因子的作用下被Janus激酶磷酸化。磷酸化的STAT蛋白转移至细胞核，在那里它们短暂地开启特定组别的细胞因子诱导基因。控制活化STAT蛋白数量的机制尚不清楚。在HeLa细胞中，经γ干扰素处理激活的STAT1蛋白被蛋白酶体抑制剂稳定化，并在体内发生泛素化。因此，活化的STAT1的数量可能受到泛素-蛋白酶体途径的负调控。
