Vinita Kumar

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STAT transcription factors signal from the plasma membrane to the nucleus in response to growth factors and cytokines. We have investigated whether plasma membrane "rafts" are involved in cytokine-activated STAT signaling. Cytokine-free human hepatoma Hep3B cells or cells treated with interleukin-6 (IL-6) or orthovanadate (a general activator of STATs) were(More)
Glucose-regulated protein 58 (GRP58/ER-60/ERp57), best known as a chaperone in the endoplasmic reticulum lumen, was previously identified by us as one of several accessory proteins in the S100 cytosol fraction of human hepatoma Hep3B cells that was differentially coshifted by anti-Stat3 antibody in an antibody-subtracted differential protein display assay.(More)
We have purified oligosaccharyltransferase from hen oviduct microsomes some 850-fold. Oligosaccharyltransferase activity copurified with a 200-kDa complex consisting of two 65-kDa polypeptides and a 50-kDa polypeptide. N-terminal sequence analysis indicated that the 50-kDa subunit was the avian form of OST48, a canine pancreatic microsomal protein(More)
Oligosaccharyltransferase (OT) catalyzes the glycosylation of asparagine residues in nascent polypeptides in the endoplasmic reticulum. In a previous communication we reported the purification and characterization of this enzyme from chicken oviduct. Here we describe the purification and sequence analysis of OT from human liver microsomes.(More)
Oligosaccharyltransferase transfers a preformed oligosaccharide from a dolichol carrier molecule to specific asparaginyl residues of proteins synthesized in the endoplasmic reticulum. We have isolated a protein complex with this activity from chicken liver microsomes with 850 fold purification. The purification procedure involved removal of peripheral and(More)
The cellular physiology of signal transducer and activator of transcription protein family (STAT) transcription factors includes activation by Tyr-phosphorylation (PY) in cytokine and growth factor receptor complexes at the level of plasma membrane rafts, subsequent cytoplasmic transit and nuclear import, and transcriptional regulation of target genes,(More)
Introduction: Primary serous papillary carcinoma of the peritoneum (PSPCP) is a rare malignant epithelial tumor that is histologically indistinguishable from papillary serous carcinoma of the ovary (PSCO). It is defined as primary tumor of peritoneum that diffusely involves the peritoneal surface but spares or only superficially invades the ovaries. Better(More)
Oligosaccharyltransferase catalyzes the transfer of oligosaccharide from a lipid dolichol to asparagine acceptor sites on nascent polypeptides. We have developed an assay for this enzyme which is based on the specific distribution of the substrate and product of the reaction in detergent solution. GlcNAc-[3H]GlcNAc-PP-Dol was synthesized for use as a(More)
We have investigated the enzyme mediating N-glycosylation in "resting" and activated lymphocytes. Normal peripheral blood lymphocytes (PBLs) were found to have low activity for glycosylation of a synthetic glycan acceptor peptide. N-glycosylation activity increased 10-fold after mitogen activation of PBLs. N-glycosylation activity remained elevated during(More)
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