Aggregation of SND1 in Stress Granules is Associated with the Microtubule Cytoskeleton During Heat Shock Stimulus.

Stress granules (SGs) are dynamic dense structures in the cytoplasm that form in response to a variety of environmental stress stimuli. Staphylococcal nuclease and Tudor domain containing 1 (SND1) is a type of RNA-binding protein and has been identified as a transcriptional co-activator. Our previous studies have shown that SND1 is a component of the stress granule, which forms under stress conditions. Here, we observed that SND1 granules were often surrounded by ɑ-tubulin-microtubules in 45°C-treated HeLa cells at 15 min or colocalized with microtubules at 30 or 45 min. Furthermore, Nocodazole-mediated microtubule depolymerization could significantly affect the efficient recruitment of SND1 proteins to the SGs during heat shock stress. In addition, the 45°C heat shock mediated the enhancement of eIF2α phosphorylation, which was not affected by treatment with Nocodazole, an agent that disrupts the cytoskeleton. The intact microtubule cytoskeletal tracks are important for the efficient assembly of SND1 granules under heat shock stress and may facilitate SND1 shuttling between cytoplasmic RNA foci. Anat Rec, 300:2192-2199, 2017. © 2017 The Authors The Anatomical Record published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists.