| Summary: | Transient receptor potential (TRP) proteins form non-selective Ca<sup>2+</sup> permeable channels that contribute to the modulation of a number of physiological functions in a variety of cell types. Since the identification of TRP proteins in <i>Drosophila</i>, it is well known that these channels are activated by stimuli that induce PIP<sub>2</sub> hydrolysis. The canonical TRP (TRPC) channels have long been suggested to be constituents of the store-operated Ca<sup>2+</sup> (SOC) channels; however, none of the TRPC channels generate Ca<sup>2+</sup> currents that resemble <i>I</i><sub>CRAC</sub>. STIM1 and Orai1 have been identified as the components of the Ca<sup>2+</sup> release-activated Ca<sup>2+</sup> (CRAC) channels and there is a body of evidence supporting that STIM1 is able to gate Orai1 and TRPC1 in order to mediate non-selective cation currents named <i>I</i><sub>SOC</sub>. STIM1 has been found to interact to and activate Orai1 and TRPC1 by different mechanisms and the involvement of TRPC1 in store-operated Ca<sup>2+</sup> entry requires both STIM1 and Orai1. In addition to the participation of TRPC1 in the <i>I</i><sub>SOC</sub> currents, TRPC1 and other TRPC proteins might play a relevant role modulating Orai1 channel function. This review summarizes the functional role of TRPC channels in the STIM1−Orai1 scenario.
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