Orai1 interacts with STIM1 and mediates capacitative Ca2+entry in mouse pulmonary arterial smooth muscle cells
| Autor: | Maria L. Valencik, Honglin Tian, Lih Chyuan Ng, Joseph R. Hume, Phillip S. Keller, Deepa Ramduny, Cherie A. Singer, Xiao-Ming Shen, Judith A. Airey |
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| Rok vydání: | 2010 |
| Předmět: |
inorganic chemicals
Male ORAI1 Protein Physiology Myocytes Smooth Muscle Pulmonary Artery Biology Muscle Smooth Vascular TRPC1 Mice Transient receptor potential channel medicine.artery medicine Animals Myocyte Stromal Interaction Molecule 1 RNA Small Interfering Cells Cultured TRPC Cation Channels Membrane Transporters Ion Channels and Pumps Membrane Glycoproteins Voltage-dependent calcium channel ORAI1 STIM1 Cell Biology Cell biology Mice Inbred C57BL Pulmonary artery Immunology Calcium Calcium Channels Intracellular |
| Zdroj: | American Journal of Physiology-Cell Physiology. 299:C1079-C1090 |
| ISSN: | 1522-1563 0363-6143 |
| DOI: | 10.1152/ajpcell.00548.2009 |
| Popis: | Previous studies in mouse pulmonary arterial smooth muscle cells (PASMCs) showed that cannonical transient receptor potential channel TRPC1 and stromal interaction molecule 1 (STIM1) mediate the sustained component of capacitative Ca2+entry (CCE), but the molecular candidate(s) that mediate the transient component of CCE remain unknown. The aim of the present study was to examine whether Orai1 mediates the transient component of CCE through activation of STIM1 in mouse PASMCs. In primary cultured mouse PASMCs loaded with fura-2, cyclopiazonic acid (CPA) caused a transient followed by a sustained rise in intracellular Ca2+concentration ([Ca2+]i). The transient but not the sustained rise in [Ca2+]iwas partially inhibited by nifedipine. The nifedipine-insensitive transient rise in [Ca2+]iand the increase in Mn2+quench of fura-2 fluorescence caused by CPA were both reduced in cells treated with Orai1 siRNA. These responses to CPA were further reduced in cells treated with Orai1 and STIM1 small interfering (si)RNA. Moreover, overexpression of STIM1 enhanced the rise in [Ca2+]iand the increase in Mn2+quench of fura-2 fluorescence caused by CPA, and these responses were reduced in cells treated with Orai1 siRNA. RT-PCR revealed Orai1 and STIM1 mRNAs, and Western blot analysis identified Orai1 and STIM1 proteins in mouse PASMCs. Furthermore, Orai1 was found to coimmunoprecipitate with STIM1, and the precipitation level of Orai1 was increased in cells subjected to store-depletion. Immunostaining revealed colocalization of Orai1 and STIM1 proteins, and the colocalization of these proteins was more apparent after store-depletion. These data provide direct evidence that the transient component of CCE is mediated by Orai1 channel as a result of STIM1 activation in mouse PASMCs. |
| Databáze: | OpenAIRE |
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