Signal transducer and activator of transcription 5b (STAT5b), the major liver-expressed STAT5 form, is phosphorylated on both tyrosine and serine in GH-stimulated cells. Although tyrosine phosphorylation is known to be critical for the dimerization, nuclear translocation, and activation of STAT5b DNA-binding and transcriptional activities, the effect of STAT5b serine phosphorylation is uncertai...

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal solid malignancies, and there is an urgent need for new therapeutic strategies based on the molecular biology of PDAC. Signal transducers and activators of transcription 5 (STAT5) are known to be activated in a variety of malignancies and involved in tumor proliferation, apoptosis, and invasion, whereas the expression and biologi...

Expression of the rat alpha(2)-macroglobulin (MG) gene undergoes dynamic changes throughout an individual's life and during the acute-phase (AP) response. Details of the participation of the STAT family of transcription factors in its control remain incompletely understood. Here we examined the involvement of STAT5b in MG gene expression during development and the AP response. Immuno-blot analy...

Antigen-induced eosinophil recruitment into the airways of sensitized mice is mediated by CD4(+) T cells and their cytokines, especially IL-5. In this study, we found that the antigen-induced airway eosinophilia was diminished in Stat5a-deficient (Stat5a(-/-)) mice and Stat5b-deficient (Stat5b(-/-)) mice. We also found that antigen-induced CD4(+) T-cell infiltration and IL-5 production in the a...

Signal transducer and activator of transcription (STAT) comprises a family of universal transcription factors that help cells sense and respond to environmental signals. STAT5 refers to two highly related proteins, STAT5A and STAT5B, with critical function: their complete deficiency is lethal in mice; in humans, STAT5B deficiency alone leads to endocrine and immunological problems, while STAT5A...

Overexpression of the epidermal growth factor receptor (EGFR) and its association with the tyrosine kinase, c-Src, is correlated with increased cellular proliferation and tumorigenesis. Previous studies have shown that EGFR and c-Src co-overexpression and association leads to the c-Src-mediated phosphorylation of tyrosine 845 of the EGFR and that mutation of Tyr(845) ablates epidermal growth fa...

Previously, we reported that whereas both signal transducers and activators of transcription (STAT) 5A and STAT5B can be activated with respect to tyrosine phosphorylation and DNA binding potential by Src kinase, only STAT5B was translocated to the nucleus, where it presumably activates unique downstream responses. To help elucidate the functional consequences of STAT5B activation by v-src, the...

Signal transducer and activator of transcription (STAT) proteins have been intensively studied in hematologic malignancies, and the efficacy of agents against STATs in lymphomas is already under research. We investigated the expression of total STAT5 and STAT5b in peripheral blood samples of patients with chronic lymphocytic leukemia (CLL) in correlation with the presence of Epstein-Barr Virus ...

Signal transducer and activator of transcription (STAT) 5b-retinoic acid receptor (RAR) a is the fifth fusion protein identified in acute promyelocytic leukemia (APL). Initially described in a patient with all-trans retinoic acid (ATRA)–unresponsive disease, STAT5b-RARa resulted from an interstitial deletion on chromosome 17. To determine the molecular mechanisms of myeloid leukemogenesis and m...

Signal transducers and activators of transcription (STATs), their inhibitors and cyclooxygenase-2 (COX-2) participate in transformations of many various types of cancers. The aim of the present study was to evaluate the relationship between STAT5A/B, COX-2, and PIAS3 mRNA expression and tumor staging, metastasis status, and histopathological subtype in 71 patients with confirmed non-small cell ...