Bidhan Bandyopadhyay - Store-operated Ca2+ signaling in dendritic cells occurs independently of STIM1

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      Publication Details (including relevant citation   information):

      J Leukoc Biol. 2011 Jan;89(1):57-62.


      SOCE via CRAC channels is a critical signaling event in immune   cells. Recent studies have identified key proteins underlying   this process; STIM is an ER Ca²+ sensor that interacts with Orai,   an intrinsic, pore-forming protein of the CRAC channel. In   heterologous expression systems, STIM1 regulates SOCE by   interacting with Orai1, -2, and -3. In native tissues, however,   the precise roles of STIM and Orai proteins are not well defined.   Here, we have investigated the molecular components of SOCE   signaling in mouse DCs. We show that DCs predominantly express   STIM2 and only very low levels of STIM1 compared with T   lymphocytes. Upon store depletion with Tg, STIM2 aggregates and   interacts selectively with Orai2. In contrast, Tg fails to   aggregate STIM1 or enhance STIM1-mediated interactions with Orai   proteins. Consistent with this biochemical characterization,   stimulation of DCs with the adhesion molecule ICAM-1 selectively   recruits STIM2 and Orai2 to the IS. Together, these data   demonstrate a novel, STIM2-dependent SOCE signaling pathway in   DCs.

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