8.A.93.1.1
TMEM97 protein (the sigma2 receptor (sigma2R); Mac30; S2R) of 176 aas and 4 TMSs in a 1 + 2 + 1 TMS arrangement (Alon et al. 2017).  It is an ER resident protein that regulates the sterol transporter, NPC1 (TC# 2.A.6.6.1). It is involved in diseases as diverse as cancer and neurological disorders (Alon et al. 2017).  TMEM97 possesses the full suite of molecular properties that define the sigma2 receptor, and Asp29 and Asp56 are essential for ligand recognition (Alon et al. 2017). It is regulated by a number of drugs (Intagliata et al. 2020). The highly specific sigma(2)R/TMEM97 ligand, FEM-1689, alleviates neuropathic pain and inhibits the integrated stress response (Yousuf et al. 2023).