Protein tyrosine phosphatase PTPεM negatively regulates PDGF β-receptor signaling induced by high glucose and PDGF in vascular smooth muscle cells

2010 ◽  
Vol 299 (5) ◽  
pp. C1144-C1152 ◽  
Author(s):  
Hidehisa Shimizu ◽  
Yoshimi Nakagawa ◽  
Chie Murakami ◽  
Naohito Aoki ◽  
Shokei Kim-Mitsuyama ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Protein Tyrosine Phosphatase ◽  
High Glucose ◽  
Tyrosine Phosphatase ◽  
Wild Type ◽  
Accelerated Atherosclerosis ◽  
Protein Tyrosine ◽  
Β Receptor ◽  
And Migration

Vascular smooth muscle cell (VSMC) proliferation and migration and vascular endothelial cell (VEC) dysfunction are closely associated with the development of atherosclerosis. We previously demonstrated that protein tyrosine phosphatase ε M (PTPεM) promotes VEC survival and migration. The present study investigates the biological functions of PTPεM in VSMCs and determines whether PTPεM is implicated in diabetes-accelerated atherosclerosis. We overexpressed wild-type and inactive PTPεM and an small interfering RNA (siRNA) of PTPεM by using an adenovirus vector to investigate the effects of PTPεM upon platelet-derived growth factor (PDGF)- and high glucose (HG)-induced responses of rat VSMCs in vitro. We found that PTPεM decreased PDGF-induced DNA synthesis and migration by reducing the phosphorylation level of the PDGF β-receptor (PDGFRβ) with subsequently suppressed H2O2 generation. The HG content in the medium generated H2O2, upregulated PDGFRβ expression and its tyrosine-phosphorylation, and elevated NADPH oxidase 1 (Nox1) expression even without exogenous PDGF, all of which were downregulated by PTPεM. The PDGFR inhibitor AG1296 also blocked HG-induced Nox1 expression and H2O2 production. Moreover, HG suppressed PTPεM expression itself, which was blocked by the antioxidant N-acetyl-l-cysteine. The effects of PTPεM siRNA were the opposite of those of wild-type PTPεM. Therefore, PTPεM negatively regulates PDGFRβ-mediated signaling pathways that are crucial for the pathogenesis of atherosclerosis, and PTPεM may be involved in diabetes-accelerated atherosclerosis.

scholarly journals Protein tyrosine phosphatase receptor type E (PTPRE) regulates the activation of wild-type KIT and KIT mutants differently

2021 ◽  
Vol 26 ◽  
pp. 100974
Author(s):  
Shaoting Zhang ◽  
Liangying Zhang ◽  
Zongying Jiang ◽  
Yue Guo ◽  
Hui Zhao ◽  
...  
Keyword(s):  
Protein Tyrosine Phosphatase ◽  
Tyrosine Phosphatase ◽  
Receptor Type ◽  
Wild Type ◽  
Protein Tyrosine

scholarly journals Loss of T-Cell Protein Tyrosine Phosphatase Induces Recycling of the Platelet-derived Growth Factor (PDGF) β-Receptor but Not the PDGF α-Receptor

2006 ◽  
Vol 17 (11) ◽  
pp. 4846-4855 ◽  
Author(s):  
Susann Karlsson ◽  
Katarzyna Kowanetz ◽  
Åsa Sandin ◽  
Camilla Persson ◽  
Arne Östman ◽  
...  
Keyword(s):  
T Cell ◽  
Growth Factor ◽  
Cell Surface ◽  
Protein Tyrosine Phosphatase ◽  
Tyrosine Phosphatase ◽  
Dominant Negative ◽  
Platelet Derived Growth Factor ◽  
Cell Protein ◽  
Protein Tyrosine ◽  
Β Receptor

We have previously shown that the T-cell protein tyrosine phosphatase (TC-PTP) dephosphorylates the platelet-derived growth factor (PDGF) β-receptor. Here, we show that the increased PDGF β-receptor phosphorylation in TC-PTP knockout (ko) mouse embryonic fibroblasts (MEFs) occurs primarily on the cell surface. The increased phosphorylation is accompanied by a TC-PTP–dependent, monensin-sensitive delay in clearance of cell surface PDGF β-receptors and delayed receptor degradation, suggesting PDGF β-receptor recycling. Recycled receptors could also be directly detected on the cell surface of TC-PTP ko MEFs. The effect of TC-PTP depletion was specific for the PDGF β-receptor, because PDGF α-receptor homodimers were cleared from the cell surface at the same rate in TC-PTP ko MEFs as in wild-type MEFs. Interestingly, PDGF αβ-receptor heterodimers were recycling. Analysis by confocal microscopy revealed that, in TC-PTP ko MEFs, activated PDGF β-receptors colocalized with Rab4a, a marker for rapid recycling. In accordance with this, transient expression of a dominant-negative Rab4a construct increased the rate of clearance of cell surface receptors on TC-PTP ko MEFs. Thus, loss of TC-PTP specifically redirects the PDGF β-receptor toward rapid recycling, which is the first evidence of differential trafficking of PDGF receptor family members.

scholarly journals AP-1 elements and TCL1 protein regulate expression of the gene encoding protein tyrosine phosphatase PTPROt in leukemia

Blood ◽  
2011 ◽  
Vol 118 (23) ◽  
pp. 6132-6140 ◽  
Author(s):  
Tasneem Motiwala ◽  
Nicola Zanesi ◽  
Jharna Datta ◽  
Satavisha Roy ◽  
Huban Kutay ◽  
...  
Keyword(s):  
Protein Tyrosine Phosphatase ◽  
Tyrosine Phosphatase ◽  
Lymphocytic Leukemia ◽  
Potential Mechanism ◽  
Wild Type ◽  
Truncated Form ◽  
Gene Encoding ◽  
Protein Tyrosine ◽  
Encoding Protein

Abstract We previously demonstrated that the gene encoding PTPROt, the truncated form of protein tyrosine phosphatase receptor type O expressed predominantly in hematopoietic cells, is a candidate tumor suppressor and is down-regulated in chronic lymphocytic leukemia (CLL). Here, we show that PTPROt expression is significantly reduced in CD19+ spleen B cells from Eμ-T cell leukemia 1 (TCL1) transgenic mice relative to the wild-type mice. Strikingly, as much as a 60% decrease in PTPROt expression occurs at 7 weeks independently of promoter methylation. To elucidate the potential mechanism for this early suppression of PTPROt in these mice, we explored the role of activating protein-1 (AP-1) in its expression. We first demonstrate that AP-1 activation by 12-O-tetradecanoylphorbol-13-acetate induces PTPROt expression with concurrent recruitment of c-fos and c-jun to its promoter. The PTPROt promoter is also responsive to over- and underexpression of AP-1, confirming the role of AP-1 in PTPROt expression. Next, we demonstrate that TCL1 can repress the PTPROt promoter by altering c-fos expression and c-jun activation state. Finally, using primary CLL cells we have shown an inverse relationship between TCL1 and PTPROt expression. These findings further substantiate the role of TCL1 in PTPROt suppression and its importance in the pathogenesis of CLL.

Sign in / Sign up

Export Citation Format

Share Document