RT Journal Article SR Electronic T1 Neutral sphingomyelinase 1 regulates cellular fitness at the level of ER stress and cell cycle JF bioRxiv FD Cold Spring Harbor Laboratory SP 2022.02.23.481585 DO 10.1101/2022.02.23.481585 A1 Dolma Choezom A1 Julia Christina Gross YR 2022 UL http://biorxiv.org/content/early/2022/02/24/2022.02.23.481585.abstract AB Neutral sphingomyelinase 1 (nSMase1) belongs to the sphingomyelinase enzyme family that hydrolyzes sphingomyelin to produce signaling active lipid ceramide and phosphorylcholine. The molecular characterization and biological function of nSMase1 remain poorly studied. Here, we report that nSMase1 (gene name: SMPD2) knockdown reduces LAMP1 at the mRNA levels and is required for initiating a full-potential unfolded protein response under ER stress. Additionally, SMPD2 KD dramatically reduces the global protein translation rate. We further show that SMPD2 KD cells are arrested in the G1 phase of the cell cycle and that two important cell cycle regulating processes - PI3K/Akt pathway and Wnt signaling pathway are altered. Taken together, we propose a role for nSMase1 in buffering ER stress and modulating cellular fitness via cell cycle regulation.