Fig. 4.

N-terminus of Orai1 anchored with STIM1 activates SOCE

STIM1 is localized primarily in the ER membrane, with a small fraction in the plasma membrane. The organization of the major predicted domains is shown, including an unpaired EF-hand and sterile-alpha motif (SAM) domains on the ER luminal side, and overlapping coiled-coil (CC) and ezrin-radixin-moesin (ERM) domains, and serine-proline-rich (S/P) and lysine-rich (K) domains on the cytosolic side. Orai1 is a plasma membrane protein with four membrane-spanning regions and intracellular N-terminus and C-terminus. It is impossible that the N-terminus of Orai1, anchored with ezrin-radixin-moesin (ERM) domain of STIM1 C-terminus, activates SOCE (Lewis, 2007)