UV light phototransduction depolarizes human melanocytes |
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Authors: | Nicholas W Bellono Elena Oancea |
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Affiliation: | Department of Molecular Pharmacology, Physiology, and Biotechnology; Brown University; Providence, RI USA |
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Abstract: | Exposure of human skin to low doses of solar UV radiation (UVR) causes increased pigmentation, while chronic exposure is a powerful risk factor for skin cancers. The mechanisms mediating UVR detection in skin, however, remain poorly understood. Our recent studies revealed that UVR activates a retinal-dependent G protein-coupled signaling pathway in melanocytes. This phototransduction pathway leads to the activation of transient receptor potential A1 (TRPA1) ion channels, elevation of intracellular calcium (Ca2+) and rapid increase in cellular melanin content. Here we report that physiological doses of solar-like UVR elicit a retinal-dependent membrane depolarization in human epidermal melanocytes. This transient depolarization correlates with delayed inactivation time of the UVR-evoked photocurrent and with sustained Ca2+ responses required for early melanin synthesis. Thus, the cellular depolarization induced by UVR phototransduction in melanocytes is likely to be a critical signaling mechanism necessary for the protective response represented by increased melanin content. |
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Keywords: | melanocyte ultraviolet phototransduction calcium signaling UV |
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