Heat Shock Protein HSP101 Affects the Release of Ribosomal Protein mRNAs for Recovery after Heat Shock

Abstract

Heat shock (HS) is known to have a profound impact on gene expression at different levels, such as inhibition of protein synthesis, in which HS blocks translation initiation and induces the sequestration of mRNAs into stress granules (SGs) or P-bodies for storage and/or decay. SGs prevent the degradation of the stored mRNAs, which can be reengaged into translation in the recovery period. However, little is known on the mRNAs stored during the stress, how these mRNAs are released from SGs afterward, and what the functional importance is of this process. In this work, we report that Arabidopsis HEAT SHOCK PROTEIN101 (HSP101) knockout mutant (hsp101) presented a defect in translation recovery and SG dissociation after HS. Using RNA sequencing and RNA immunoprecipitation approaches, we show that mRNAs encoding ribosomal proteins (RPs) were preferentially stored during HS and that these mRNAs were released and translated in an HSP101-dependent manner during recovery. By 15 N incorporation and polysome profile analyses, we observed that these released mRNAs contributed to the production of new ribosomes to enhance translation. We propose that, after HS, HSP101 is required for the efficient release of RP mRNAs from SGs resulting in a rapid restoration of the translation machinery by producing new RPs.

ATP Hydrolysis Determines Cold Tolerance by Regulating Available Energy for Glutathione Synthesis in Rice Seedling Plants

“…Heat shock protein is always accumulated to confer heat tolerance in plants under heat stress (Merret et al 2017;Islam et al 2019;Jiang et al 2020;Li et al 2020). It is worth noting that, similar results were also found in the rice plants under cold stress, in which higher increase in expression levels of HSP71.1 and HSP24.1 were found in the cold resistant plants than the cold susceptible one compared with their respective controls (Fig.…”

The YTH Domain Protein ECT2 Is an m6A Reader Required for Normal Trichome Branching in Arabidopsis

“…Since ECT2 does not appear to form foci under normal growth conditions, we postulated that it associates in SGs rather than P-bodies. We next ran colocalization experiments using a stable line coexpressing both YFP-ECT2 and RFP-PAB2, a canonical marker of SGs (Weber et al, 2008;Merret et al, 2017) (Figures 10C and 10D). As expected, both the YFP and RFP signals appeared as discrete foci in the cytosol in response to heat stress, and the vast majority of them overlapped (merged panels in Figure 10C).…”

Polysomes, Stress Granules, and Processing Bodies: A Dynamic Triumvirate Controlling Cytoplasmic mRNA Fate and Function

“…Typically, mRNAs stored in SGs are translationally competent and can reenter the translational pool once released. In plants, this is exemplified by Arabidopsis mRNAs encoding ribosomal proteins that are preferentially stored in SGs under heat shock stress and released and translated during recovery through a mechanism that requires HEAT SHOCK PROTEIN101 (HSP101; Merret et al, 2017).…”