Potent functional uncoupling between STIM1 and Orai1 by dimeric 2-aminodiphenyl borinate analogs

Eunan Hendron, Xizhuo Wang, Yandong Zhou, Xiangyu Cai, Jun Ichi Goto, Katsuhiko Mikoshiba, Yoshihiro Baba, Tomohiro Kurosaki, Youjun Wang, Donald L. Gill

Research output: Contribution to journalArticlepeer-review

34 Scopus citations


The coupling of ER Ca2+-sensing STIM proteins and PM Orai Ca2+ entry channels generates "store-operated" Ca2+ signals crucial in controlling responses in many cell types. The dimeric derivative of 2-aminoethoxydiphenyl borinate (2-APB), DPB162-AE, blocks functional coupling between STIM1 and Orai1 with an IC50 (200nM) 100-fold lower than 2-APB. Unlike 2-APB, DPB162-AE does not affect L-type or TRPC channels or Ca2+ pumps at maximal STIM1-Orai1 blocking levels. DPB162-AE blocks STIM1-induced Orai1 or Orai2, but does not block Orai3 or STIM2-mediated effects. We narrowed the DPB162-AE site of action to the STIM-Orai activating region (SOAR) of STIM1. DPB162-AE does not prevent the SOAR-Orai1 interaction but potently blocks SOAR-mediated Orai1 channel activation, yet its action is not as an Orai1 channel pore blocker. Using the SOAR-F394H mutant which prevents both physical and functional coupling to Orai1, we reveal DPB162-AE rapidly restores SOAR-Orai binding but only slowly restores Orai1 channel-mediated Ca2+ entry. With the same SOAR mutant, 2-APB induces rapid physical and functional coupling to Orai1, but channel activation is transient. We infer that the actions of both 2-APB and DPB162-AE are directed toward the STIM1-Orai1 coupling interface. Compared to 2-APB, DPB162-AE is a much more potent and specific STIM1/Orai1 functional uncoupler. DPB162-AE provides an important pharmacological tool and a useful mechanistic probe for the function and coupling between STIM1 and Orai1 channels.

Original languageEnglish (US)
Pages (from-to)482-492
Number of pages11
JournalCell Calcium
Issue number6
StatePublished - 2014

All Science Journal Classification (ASJC) codes

  • Physiology
  • Molecular Biology
  • Cell Biology


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