The ER/PM microdomain, PI(4,5)P2 and the regulation of STIM1-Orai1 channel function

- ER/PM microdomains are formed by tethering proteins such as the E-syts VAPs and the yeast homologues of Ist2.
- The ER/PM microdomains are divided to PI(4,5)P2-poor and PI(4,5)P2-rich domains.
- Dynamic translocation between the PI(4,5)P2-poor and PI(4,5)P2-rich domains is a new form of regulation of proteins in the ER/PM microdomains.
- Translocation of the Orai1-STIM1 complex from the PI(4,5)P2-poor to the PI(4,5)P2-rich domains determines STIM1 conformation and Orai1 gating by Ca2+.