Cytokines induce the tyrosine phosphorylation and associated activation of signal transducers and activators of transcription (Stat). The mechanisms by which this response is terminated are largely unknown. Among a variety of inhibitors examined, the proteasome inhibitors MG132 and lactacystin affected Stat4, Stat5 and Stat6 turnover by significantly stabilizing the tyrosine-phosphorylated form...

Lymphocyte homeostasis requires coordination of metabolic processes with cellular energetic and biosynthetic demands but mechanisms that regulate T-cell metabolism are uncertain. We show that interleukin-7 (IL-7) is a key regulator of glucose uptake in T lymphocytes. To determine how IL-7 affects glucose uptake, we analyzed IL-7 signaling mechanisms and regulation of the glucose transporter, Gl...

Signal transducers and activators of transcription (STATs) have been reported to play a critical role in the differentiation of several myeloid cell lines, although the importance of STATs in the differentiation of primary human hematopoietic cells remains to be established. Terminal eosinophil differentiation is induced by interleukin-5 (IL-5), which has also been demonstrated to activate STAT...

Cytokine-inducible SH2 domain-containing protein (CISH), a member of the suppressor of cytokine signaling family of negative feedback regulators, is induced by cytokines that activate STAT5 and can inhibit STAT5 signaling in vitro. However, demonstration of a definitive in vivo role for CISH during development has remained elusive. This study employed expression analysis and morpholino-mediated...

Granulocyte-macrophage colony-stimulating factor (GM-CSF) induces immediate effects in monocytes by activation of the Janus kinase (JAK2) and STAT transcription factor (STAT5) pathway. Recent studies have identified homologues of STAT5, STAT5A, and STAT5B, as well as lower molecular weight variants of STAT5. To define the activation of the STAT5 homologues and lower molecular weight variant in ...

STAT5 proteins are constitutively activated in malignant cells from many patients with leukemia, including the myeloproliferative neoplasms (MPNs) chronic myeloid leukemia (CML) and polycythemia vera (PV), but whether STAT5 is essential for the pathogenesis of these diseases is not known. In the present study, we used mice with a conditional null mutation in the Stat5a/b gene locus to determine...

Although prolactin and interleukin 2 (IL-2) can elicit distinct physiological responses, we have found that their signal pathways share a common signal transducer and activator of transcription, STAT5. STAT5 was originally identified as a mammary gland factor induced by prolactin in lactating breast cells. Here we demonstrate that STAT5 is activated after IL-2 stimulation of two responsive lymp...

Signals initiated by the IL7R are required for B cell development. However, the roles that distinct IL7R-induced signaling pathways play in this process remains unclear. To identify the function of the Raf and STAT5 pathways in IL7R-dependent B cell development, we used transgenic mice that express constitutively active forms of Raf (Raf-CAAX) or STAT5 (STAT5b-CA) throughout lymphocyte developm...

Hyperactivation of the transcription factor Stat5 leads to various leukemias. Stat5 activity is regulated by the protein phosphatase SHP-1 in a phospholipase C (PLC)-β3-dependent manner. Thus, PLC-β3-deficient mice develop myeloproliferative neoplasm, like Lyn (Src family kinase)- deficient mice. Here we show that Lyn/PLC-β3 doubly deficient lyn(-/-);PLC-β3(-/-) mice develop a Stat5-dependent, ...

Lymphocyte homeostasis requires coordination of metabolic processes with cellular energetic and biosynthetic demands but mechanisms that regulate T-cell metabolism are uncertain. We show that interleukin-7 (IL-7) is a key regulator of glucose uptake in T lymphocytes. To determine how IL-7 affects glucose uptake, we analyzed IL-7 signaling mechanisms and regulation of the glucose transporter, Gl...