Essential role of the N-terminus of murine Orai1 in store-operated Ca2+ entry.
Store-operated Ca(2+) entry (SOCE) is a physiologically important process that is triggered by intracellular Ca(2+) depletion. Recently, human Orai1 (the channel-forming subunit) and STIM1 (the calcium sensor) were identified as essential molecules for SOCE. Here, we report the cloning and functional analysis of three murine orthologs of Orai1, termed Orai1, 2, and 3. Among the genes identified, Orai1 contains a distinctive proline- and arginine-rich N-terminal cytoplasmic sequence. Co-expression of STIM1 with Orai1 produced a marked effect on SOCE, while co-expression with Orai2 or Orai3 had little effect. Expression of Orai1 without its N-terminal tail had a marginal effect on SOCE, while chimeric Orai2 containing the Orai1 N-terminus produced a marked increase in SOCE. In addition, a truncated version of Orai1 containing the N-terminus without the pore-forming transmembrane domain had a dominant negative effect on SOCE. These results reveal the essential role of Orai1 and its N-terminal sequence in SOCE.
Takahashi
Yoichiro
Y
Second Department of Internal Medicine, Akita University School of Medicine, Akita, Japan.
Murakami
Manabu
M
Watanabe
Hiroyuki
H
Hasegawa
Hitoshi
H
Ohba
Takayoshi
T
Munehisa
Yoshiko
Y
Nobori
Kiyoshi
K
Ono
Kyoichi
K
Iijima
Toshihiko
T
Ito
Hiroshi
H
D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002460:Cell Line; D003001:Cloning, Molecular; D020869:Gene Expression Profiling; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D000071740:ORAI1 Protein; D000071741:ORAI2 Protein; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D034622:RNA Interference; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D000071737:Stromal Interaction Molecule 1; D014162:Transfection
D015220:Calcium Channels; D008562:Membrane Glycoproteins; D000071740:ORAI1 Protein; D000071741:ORAI2 Protein; C520430:Orai1 protein, mouse; C520431:Orai2 protein, mouse; C520432:Orai3 protein, mouse; D020033:Protein Isoforms; D011993:Recombinant Fusion Proteins; C100757:Stim1 protein, mouse; D000071737:Stromal Interaction Molecule 1; D049452:Green Fluorescent Proteins; D002118:Calcium