Inhibition of tRNA synthetase activity prevents the assembly of stress granules and P-bodies despite activation of the integrated stress response.
Absolute Event Rate: 0% vs 100%
Translation elongation defects activate the integrated stress response (ISR), but whether and how ribosome stalls are cleared to enable mRNA release for ribonucleoprotein (RNP) granule assembly remain unclear. We show that blocking tRNA aminoacylation generates persistent uncollided ribosome stalls that inhibit stress granule and P-body assembly despite robust ISR activation. Collided ribosomes are rapidly cleared by ZNF598-dependent ribosome-associated quality control within 4 h, while uncollided stalls resist clearance and persist for >16 h. Puromycin releases persistent stalls and restores RNP granule formation. The block in stress granule assembly is generalizable across tRNA synthetase inhibitors and amino acid deprivation. Therefore, stress granules represent signal integrators reporting translation elongation status when initiation is suppressed. Our findings reveal that translation quality control pathways selectively clear collided ribosomes, establish that translation elongation stress uncouples RNP granule assembly from the ISR, and suggest that tolerating uncollided stalls may be adaptive for cotranslational processes essential for cellular function.
Baymiller et al. (Wed,) conducted a other in tRNA synthetase inhibition. halofuginone vs. arsenite, thapsigargin was evaluated on Assembly of stress granules (SGs) and processing bodies (P-bodies). Inhibition of tRNA synthetase activity prevents the assembly of stress granules and P-bodies despite activation of the integrated stress response.