Assembly of stress granules requires microfilaments and microtubules

LOSCHI, MARIELA; BOCCACCIO, GRACIELA L.

Pinamar, Argentina

Congreso; XLI reunión SAIB; 2005

Stress granules (SGs) are phase-dense organelles that appear transiently in the perinuclear region of eukaryotic cells upon induction of enviromental stress (e.g. heat, oxidative agents, UV, etc). SG assembly is triggered by an abortive translational initiation that leads to the accumulation of stalled preinitiation complexes along with RNA-binding proteins (TIA-1/R, HuR, Staufen, etc). SGs are proposed to serve as a triage site that controls the fate of untranslated mRNAs. Our goal is to evaluate the participation of the cytoskeleton and molecular motors in the collapse into SGs of the translational machinery, normally dispersed throughout the cytoplasm. We tested the effect of different microtubule and microfilament-disrupting drugs on SG formation upon exposure of cultured cells to oxidative stress-inducing agents. We found that cytoskeleton–disrupting treatments cause dramatic changes on SG assembly. Disruption of the microtubule network prior to stress induction provokes the formation of SGs of normal size that fail to localize perinuclearly. Disruption of the actin network induces the accumulation of a larger number of smaller SGs that remain dispersed throughout the cytoplasm. Our results suggests a role for the cytoskeleton for the anchorage and/or for the transport of stress-granule components to the perinuclear region.