FAM98A is localized to stress granules and associates with multiple stress granule-localized proteins

Stress granules are evolutionally conserved ribonucleoprotein structures that are formed in response to various stress stimuli. Recent studies have demonstrated that proteins with low complexity (LC) regions play a critical role for the formation of stress granules. In this study, we report that FAM98A, whose biological functions are unknown, is a novel component of stress granules. FAM98A is localized to stress granules, but not to P-bodies, after various stress stimuli. Analysis with deletion mutants revealed that C-terminal region that contains LC region was essential for FAM98A accumulation to stress granules. Depletion of FAM98A using two different siRNAs decreased the number of stress granules formed per cell. Finally, we show that FAM98A associates with stress granule-localized proteins, such as DDX1, ATXN2, ATXN2L, and NUFIP2. Our results show a partial role of FAM98A for the organization of stress granules.