scholarly journals Sumoylated protein tyrosine phosphatase 1B localizes to the inner nuclear membrane and regulates the tyrosine phosphorylation of emerin

2012 ◽  
Vol 125 (2) ◽  
pp. 310-316 ◽  
Author(s):  
S.-C. Yip ◽  
S. Cotteret ◽  
J. Chernoff
Keyword(s):  
Tyrosine Phosphorylation ◽  
Nuclear Membrane ◽  
Protein Tyrosine Phosphatase ◽  
Tyrosine Phosphatase ◽  
Protein Tyrosine Phosphatase 1B ◽  
Protein Tyrosine ◽  
Inner Nuclear Membrane

scholarly journals Protein Tyrosine Phosphatase 1B Attenuates Growth Hormone-Mediated JAK2-STAT Signaling

2003 ◽  
Vol 23 (11) ◽  
pp. 3753-3762 ◽  
Author(s):  
Feng Gu ◽  
Nadia Dubé ◽  
Jin Wook Kim ◽  
Alan Cheng ◽  
Maria de Jesus Ibarra-Sanchez ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
Protein Tyrosine Phosphatase ◽  
Tyrosine Phosphatase ◽  
Cytokine Signaling ◽  
Tyrosine Kinase Domain ◽  
Protein Tyrosine Phosphatase 1B ◽  
Protein Tyrosine ◽  
Ptp 1B

ABSTRACT Protein tyrosine phosphatase-1B (PTP-1B) attenuates insulin, PDGF, EGF, and IGF-I signaling by dephosphorylating tyrosine residues located in the tyrosine kinase domain of the corresponding receptors. More recently, PTP-1B was shown to modulate the action of cytokine signaling via the nonreceptor tyrosine kinase JAK2. Transmission of the growth hormone (GH) signal also depends on JAK2, raising the possibility that PTP-1B modulates GH action. Consistent with this hypothesis, GH increased the abundance of tyrosine-phosphorylated JAK2 associated with a catalytically inactive mutant of PTP-1B. GH-induced JAK2 phosphorylation was greater in knockout (KO) than in wild-type (WT) PTP-1B embryonic fibroblasts and resulted in increased tyrosine phosphorylation of STAT3 and STAT5, while overexpression of PTP-1B reduced the GH-mediated activation of the acid-labile subunit gene. To evaluate the in vivo relevance of these observations, mice were injected with GH under fed and fasted conditions. As expected, tyrosine phosphorylation of JAK2 and STAT5 occurred readily in the livers of fed WT mice and was almost completely abolished during fasting. In contrast, resistance to the action of GH was severely impaired in the livers of fasted KO mice. These results indicate that PTP-1B regulates GH signaling by reducing the extent of JAK2 phosphorylation and suggest that PTP-1B is essential for limiting the action of GH during metabolic stress such as fasting.

scholarly journals Protein Tyrosine Phosphatase 1B Regulates Pyruvate Kinase M2 Tyrosine Phosphorylation

2013 ◽  
Vol 288 (24) ◽  
pp. 17360-17371 ◽  
Author(s):  
Ahmed Bettaieb ◽  
Jesse Bakke ◽  
Naoto Nagata ◽  
Kosuke Matsuo ◽  
Yannan Xi ◽  
...  
Keyword(s):  
Tyrosine Phosphorylation ◽  
Pyruvate Kinase ◽  
Protein Tyrosine Phosphatase ◽  
Tyrosine Phosphatase ◽  
Protein Tyrosine Phosphatase 1B ◽  
Protein Tyrosine ◽  
Pyruvate Kinase M2

Inhibition of Protein Tyrosine Phosphatase 1B by Lutein Derivatives isolated from Mexican Oregano (Lippia graveolens)

2018 ◽  
Vol 17 (3) ◽  
pp. 134-139
Author(s):  
R.M. Perez-Gutierrez
Keyword(s):  
Protein Tyrosine Phosphatase ◽  
Inhibitory Activity ◽  
Spectroscopic Data ◽  
Methanol Extract ◽  
Tyrosine Phosphatase ◽  
Positive Control ◽  
Protein Tyrosine Phosphatase 1B ◽  
Protein Tyrosine ◽  
Ic50 Value ◽  
Ic50 Values

Methanol extract from Lippia graveolens (Mexican oregano) was studied in order to identify inhibitory bioactives for protein tyrosine phosphatase 1B (PTP1B). Known flavone as lutein (1), and another flavone glycoside such as lutein-7-o-glucoside (2), 6-hydroxy-lutein-7-ohexoside (3) and lutein-7-o-ramnoide (4) were isolated from methanol extract of aerial parts of the Lippia graveolens. All isolates were identified based on extensive spectroscopic data analysis, including UV, IR, NMR, MS and compared with spectroscopic data previously reported. These flavones were evaluated for PTP1B inhibitory activity. Among them, compounds 1 and 3 displayed potential inhibitory activity against PTP1B with IC50 values of 7.01 ± 1.25 μg/ml and 18.4 μg/ml, respectively. In addition, compound 2 and 4 showed moderate inhibitory activity with an IC50 value of 23.8 ± 6.21 and 67.8 ± 5.80 μg/ml respectively. Among the four compounds, luteolin was found to be the most potent PTP1B inhibitor compared to the positive control ursolic acid, with an IC50 value of 8.12 ± 1.06 μg/ml. These results indicate that flavonoids constituents contained in Lippia graveolens can be considered as a natural source for the treatment of type 2 diabetes.

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