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Proc Natl Acad Sci U S A. 2012 Apr 24;109(17):6745-50. doi: 10.1073/pnas.1114193109. Epub 2012 Apr 9.

Redox signal-mediated sensitization of transient receptor potential melastatin 2 (TRPM2) to temperature affects macrophage functions.

Author information

1
Division of Cell Signaling, Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki 444-8787, Japan.

Abstract

The ability to sense temperature is essential for organism survival and efficient metabolism. Body temperatures profoundly affect many physiological functions, including immunity. Transient receptor potential melastatin 2 (TRPM2) is a thermosensitive, Ca(2+)-permeable cation channel expressed in a wide range of immunocytes. TRPM2 is activated by adenosine diphosphate ribose and hydrogen peroxide (H(2)O(2)), although the activation mechanism by H(2)O(2) is not well understood. Here we report a unique activation mechanism in which H(2)O(2) lowers the temperature threshold for TRPM2 activation, termed "sensitization," through Met oxidation and adenosine diphosphate ribose production. This sensitization is completely abolished by a single mutation at Met-214, indicating that the temperature threshold of TRPM2 activation is regulated by redox signals that enable channel activity at physiological body temperatures. Loss of TRPM2 attenuates zymosan-evoked macrophage functions, including cytokine release and fever-enhanced phagocytic activity. These findings suggest that redox signals sensitize TRPM2 downstream of NADPH oxidase activity and make TRPM2 active at physiological body temperature, leading to increased cytosolic Ca(2+) concentrations. Our results suggest that TRPM2 sensitization plays important roles in macrophage functions.

PMID:
22493272
PMCID:
PMC3340098
DOI:
10.1073/pnas.1114193109
[Indexed for MEDLINE]
Free PMC Article

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