|Description||PTP-1B Protein, Active, Agarose Conjugate, 50 µg|
|Overview||Dephosphorylates tyrosine-phosphorylated peptides and proteins|
|Application||Active, agarose conjugate. Dephosphorylates tyrosine-phosphorylated peptides & proteins, for use in Phosphatase Assays.|
|Safety Information according to GHS|
|Storage and Shipping Information|
|Storage Conditions||1 year at -20 C|
|Material Size||50 µg|
|Reference overview||Application||Pub Med ID|
|Insulin regulates the dynamic balance between Ras and Rap1 signaling by coordinating the assembly states of the Grb2-SOS and CrkII-C3G complexes|
Okada, S., et al
Embo J, 17:2554-65 (1998) 1998
|Interferon gamma-dependent induction of human intercellular adhesion molecule-1 gene expression involves activation of a distinct STAT protein complex|
Naik, S. M., et al
J Biol Chem, 272:1283-90 (1997) 1997
|Negative regulation of the growth-promoting transcription factor E2F-1 by a stably bound cyclin A-dependent protein kinase|
Krek, W., et al
Cell, 78:161-72 (1994) 1994
|Mammary gland factor (MGF) is a novel member of the cytokine regulated transcription factor gene family and confers the prolactin response.|
Wakao, H, et al.
EMBO J., 13: 2182-91 (1994) 1994
Milk protein gene expression in mammary epithelial cells is regulated by the action of the lactogenic hormones insulin, glucocorticoids and prolactin. The mammary gland factor, MGF, has been shown to be a central mediator in the lactogenic hormone response. The DNA binding activity of MGF is hormonally regulated and essential for beta-casein promoter activity. We have used Red A Sepharose- and sequence-specific DNA affinity chromatography to purify MGF from mammary gland tissue of lactating sheep. Proteins of 84 and 92 kDa were obtained, proteolytically digested and the resulting peptides separated by reverse phase high pressure liquid chromatography. The 84 and 92 kDa proteins yielded very similar peptide patterns. The amino acid sequence of two peptides was determined. The sequence information was used to derive oligonucleotide probes. A cDNA library from the mRNA of mammary gland tissue of lactating sheep was screened and a molecular clone encoding MGF was isolated. MGF consists of 734 amino acids and has sequence homology with the 113 (Stat113) and 91 kDa (Stat91) components of ISGF3, transcription factors which are signal transducers of IFN-alpha/beta and IFN-gamma. Two species of MGF mRNA of 6.5 and 4.5 kb were detected in mammary gland tissue of lactating sheep. Lower mRNA expression was found in ovary, thymus, spleen, kidney, lung, muscle and the adrenal gland. MGF cDNA was incorporated into a eukaryotic expression vector and cotransfected with a vector encoding the long form of the prolactin receptor into COS cells. A strong MGF-specific bandshift was obtained with nuclear extracts of COS cells induced with prolactin. Treatment of activated MGF with a tyrosine-specific protein phosphatase resulted in the loss of DNA binding activity. Prolactin-dependent transactivation of a beta-casein promoter-luciferase reporter gene construct was observed in transfected cells.
|The nontransmembrane tyrosine phosphatase PTP-1B localizes to the endoplasmic reticulum via its 35 amino acid C-terminal sequence.|
Frangioni, J V, et al.
Cell, 68: 545-60 (1992) 1992
We report the first intracellular characterization of an endogenous nontransmembrane protein tyrosine phosphatase (PTP). Using affinity-purified polyclonal antibodies, we have identified PTP-1B as a 50 kd serine phosphoprotein in immunoprecipitation and immunoblotting assays. Surprisingly, indirect immunofluorescence experiments indicate that PTP-1B is localized predominantly in the endoplasmic reticulum (ER). Subcellular fractionation is consistent with this localization and establishes that PTP-1B is tightly associated with microsomal membranes, with its phosphatase domain oriented towards the cytoplasm. The C-terminal 35 amino acids of PTP-1B are both necessary and sufficient for targeting to the ER. The finding of a tyrosine phosphatase on the ER suggests new possibilities for cellular events controlled by tyrosine phosphorylation.