8.A.141. The Eros Chaperone Protein (Eros) Family
In response to extracellular ATP, the purinergic receptor P2X7 mediates various biological processes, including phosphatidylserine (PtdSer) exposure, phospholipid scrambling, dye uptake, ion transport, and interleukin (IL)-1beta production. A transmembrane protein, 'Essential for reactive oxygen species' (Eros) is a necessary protein for P2X7 expression (Ryoden et al. 2020). An Eros-null mouse T cell line lost the ability to expose PtdSer, to scramble phospholipids, and to internalize a dye, YO-PRO-1, and Ca2+. The eros-null mutation abolished the ability of macrophages to secrete IL-1beta in response to ATP. Eros is localized to the endoplasmic reticulum and functions as a chaperone for NADPH oxidase components. Similarly, Eros at the endoplasmic reticulum transiently associates with P2X7 to promote the formation of a stable homotrimeric complex of P2X7. Thus, Eros acts as a chaperone not only for NADPH oxidase, but also for P2X7, and it contributes to the innate immune reaction (Ryoden et al. 2020).