MID-type transmembrane mechanosensor of the CWI pathway; O-glycosylated integral plasma membrane protein; acts as a sensor for cell wall integrity (CWI) signaling and activates the pathway; interacts with Rom2p, a guanine nucleotide exchange factor for Rho1p, and with cell integrity pathway protein Zeo1p; required for heat-induced phosphorylation of Ssa1p by Pkc1p resulting in epichaperome rearrangement and fine tuning of multiple cellular processes; functionally analogous to mammalian integrins