TWO TYPES OF STORE-OPERATED CHANNELS IN A431 CELLS
K. O. Gusev, A. N. Zubov, E. V. Kaznacheyeva, G. N. Mozhayeva 1
Institute of Cytology RAS, St. Petersburg, Russia;
1 e-mail: gnmozh@link.cytspb.rssi.ru
Activation of phospholipase C-coupled receptors leads to the release of бр2+ from бр2+
stores, and subsequent activation of store-operated cation (SOC) channels, promoting sustained бр2+ influx.
The most studied SOC channels are CRAC ("calcium-release activated calcium") channels exhibiting a very high selectivity
for бр2+. However, there are many SOC channels permeable for бр2+ but having a lower selectivity.
And while бр2+ influx is important for many biological processes, little is known about the types of SOC channels
and mechanisms of SOC channel activation. Previously, we described store-operated Imin channels in A431 cells.
Here, by whole-cell recordings, we demonstrated that the store depletion activates two types of current in A431 cells - highly
selective for divalent cations (presumably, ICRAC), and moderately selective (ISOC supported
by Imin channels). These currents can be registered separately and have different developing time and amplitude.
Coexisting of two different types of SOC channels in A431 cells seems to facilitate the control of intracellular бр2+-dependent
processes.
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