8.A.41 The Stretch-activated Calcium Channel Auxiliary Protein, Mid1 (Mid1) Family
The Mid1 protein in Saccharomyces cerevisiae forms a complex with the Cch1 calcium channel (TC# 1.A.1.11.10) and the Ecm7 protein (TC# 1.H.1.4.6). The Mid1 protein appears to be essentially required for activity of Cch1 which is homologous to VIC family alpha subunits. Mid1 proteins always have an N-terminal TMS, sometimes have a C-terminal TMS, and have been reported to have as many as 4 TMSs. The Ecm7 protein is a homologue of claudins, some of which have been reported to have channel activity.