Regulation of TRP channel TRPM2 by the tyrosine phosphatase PTPL1
| Autor: | Jocelyn Wozney, Kathleen Conrad, Barbara A. Miller, Wenyi Zhang, Joseph Y. Cheung, Qin Tong |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Time Factors
Cell Survival Physiology Protein Tyrosine Phosphatase Non-Receptor Type 13 TRPM Cation Channels Apoptosis Protein tyrosine phosphatase Transfection Receptor tyrosine kinase Necrosis Transient receptor potential channel Protein Interaction Mapping Humans Immunoprecipitation TRPM2 Calcium Signaling Phosphorylation RNA Small Interfering Tyrosine Protein Kinase Inhibitors biology Tumor Necrosis Factor-alpha Hydrogen Peroxide U937 Cells Cell Biology Genistein Molecular biology Oxidative Stress Pyrimidines biology.protein RNA Interference Protein Tyrosine Phosphatases Platelet-derived growth factor receptor Protein Binding |
| Zdroj: | American Journal of Physiology-Cell Physiology. 292:C1746-C1758 |
| ISSN: | 1522-1563 0363-6143 |
| DOI: | 10.1152/ajpcell.00569.2006 |
| Popis: | TRPM2, a member of the transient receptor potential (TRP) superfamily, is a Ca2+-permeable channel, which mediates susceptibility to cell death following activation by oxidative stress, TNFα, or β-amyloid peptide. We determined that TRPM2 is rapidly tyrosine phosphorylated after stimulation with H2O2or TNFα. Inhibition of tyrosine phosphorylation with the tyrosine kinase inhibitors genistein or PP2 significantly reduced the increase in [Ca2+]iobserved after H2O2or TNFα treatment in TRPM2-expressing cells, suggesting that phosphorylation is important in TRPM2 activation. Utilizing a TransSignal PDZ domain array blot to identify proteins which interact with TRPM2, we identified PTPL1 as a potential binding protein. PTPL1 is a widely expressed tyrosine phosphatase, which has a role in cell survival and tumorigenesis. Immunoprecipitation and glutathione- S-transferase pull-down assays confirmed that TRPM2 and PTPL1 interact. To examine the ability of PTPL1 to modulate phosphorylation or activation of TRPM2, PTPL1 was coexpressed with TRPM2 in human embryonic kidney-293T cells. This resulted in significantly reduced TRPM2 tyrosine phosphorylation, and inhibited the rise in [Ca2+]iand the loss of cell viability, which follow H2O2or TNFα treatment. Consistent with these findings, reduction in endogenous PTPL1 expression with small interfering RNA resulted in increased TRPM2 tyrosine phosphorylation, a significantly greater rise in [Ca2+]ifollowing H2O2treatment, and enhanced susceptibility to H2O2-induced cell death. Endogenous TRPM2 and PTPL1 was associated in U937-ecoR cells, confirming the physiological relevance of this interaction. These data demonstrate that tyrosine phosphorylation of TRPM2 is important in its activation and function and that inhibition of TRPM2 tyrosine phosphorylation reduces Ca2+influx and protects cell viability. They also suggest that modulation of TRPM2 tyrosine phosphorylation is a mechanism through which PTPL1 may mediate resistance to cell death. |
| Databáze: | OpenAIRE |
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