Open AccessSTIM1 interacts with termini of Orai channels in a sequential manner
Author(s) -
Liling Niu,
Fuyun Wu,
Kaili Li,
Jing Li,
Shenyuan L. Zhang,
Junjie Hu,
Qian Wang
Publication year - 2020
Publication title -
journal of cell science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.384
H-Index - 278
eISSN - 1477-9137
pISSN - 0021-9533
DOI - 10.1242/jcs.239491
Subject(s) - stim1 , endoplasmic reticulum , orai1 , microbiology and biotechnology , gating , biology , immunoprecipitation , biophysics , biochemistry , gene
Store-operated calcium entry (SOCE) is critical for numerous calcium-related processes. The activation of SOCE requires engagement between stromal interaction molecule 1 (STIM1) molecules on the endoplasmic reticulum and Ca2+ release-activated Ca2+ channel (CRAC) Orai on the plasma membrane. However, the molecular details of their interactions remain elusive. Here, we analyzed STIM1-Orai interactions using synthetic peptides derived from the N- and C-termini of Orai channels (Orai-NT and Orai-CT, respectively) and purified fragments of STIM1. The binding of STIM1 to Orai-NT is hydrophilic-based, whereas binding to the Orai-CT is mostly hydrophobic. STIM1 decreases its affinity for Orai-CT when Orai-NT is present, supporting a stepwise interaction. Orai3-CT exhibits stronger binding to STIM1 than Orai1-CT, largely due to the shortness of one helical turn. The role of newly identified residues was confirmed by co-immunoprecipitation and calcium imaging using full-length molecules. Our results provide important insight into CRAC channel gating by STIM1.