Project description:To adapt mitochondrial function to the ever-changing intra- and extra-cellular environment, multiple mitochondrial stress response (MSR) pathways, including the mitochondrial unfolded protein response (UPRmt), have evolved. However, how the mitochondrial stress signal is sensed and relayed to UPRmt transcription factors, such as ATFS-1 in Caenorhabditis elegans, remains largely unknown. Here, we show that a panel of vacuolar H+-ATPase (v-ATPase) subunits and the target of rapamycin complex 1 (TORC1) activity are essential for the cytosolic relay of mitochondrial stress to ATFS-1, and for the induction of the UPRmt. Mechanistically, mitochondrial stress stimulates v-ATPase/Rheb-dependent TORC1 activation, subsequently promoting ATFS-1 translation. Increased translation of ATFS-1 upon mitochondrial stress furthermore relies on a set of ribosomal components, but is independent of GCN-2/PEK-1 signaling. Finally, the v-ATPase and ribosomal subunits are required for mitochondrial surveillance and mitochondrial stress-induced longevity. These results reveal a v-ATPase-TORC1-ATFS-1 signaling pathway that links mitochondrial stress to the UPRmt through intimate crosstalks between multiple organelles.
Project description:ATFS-1 has been shown to regulate transcription of mitochondrial chaperone genes such as mtHsp70/hsp-6 and hsp-60 in response to mitocondrial stress. To identify the entire ATFS-1-mediated response, we compared the transcript profiles from wild-type and atfs-1(tm4525) worms raised in the absence and presence of mitochondrial stress. We used microarrays to identify genes regulated by ATFS-1 during mitochondrial stress RNA samples were prepared from wild-type(wt) and atfs-1(tm4525)(mutant) worms fed either control(RNAi) or spg-7(RNAi). Worms were synchronized by bleaching, raised in liquid culture and harvested at the L4 stage. Control is denoted as C and spg-7 treatment is denoted T. Each experiment was performed in triplicate indicated as 1,2 and 3.
Project description:ATFS-1 has been shown to regulate transcription of mitochondrial chaperone genes such as mtHsp70/hsp-6 and hsp-60 in response to mitocondrial stress. To identify the entire ATFS-1-mediated response, we compared the transcript profiles from wild-type and atfs-1(tm4525) worms raised in the absence and presence of mitochondrial stress. We used microarrays to identify genes regulated by ATFS-1 during mitochondrial stress
Project description:We previously reported that the RNA endonculease HOE-1 (RNaseZ/ELAC2) is necessary and sufficient for activation of the mitochondrial unfolded protein response (UPRmt) in C. elegans (PMID: 35451962). To comprehensively assess the broader cellular consequences of increased nuclear activity of HOE-1, we conducted RNA sequencing on day 2 adult wildtype animals vs animals in which endogenous HOE-1 is elevated in the nucleus via perturbation of its nuclear export signal (hoe-1(ΔNES)). Additionally, wildtype and hoe-1(ΔNES) animals were grown on both control and atfs-1 RNAi (ATFS-1 is the central transcription factor for UPRmt) to determine gene expression that is atfs-1 dependent. This analysis revealed that differential gene expression in hoe-1(ΔNES) animals exhibits a strong mitochondrial signature. Notably, gene ontology (GO) analysis of significantly upregulated genes showed a significant overrepresentation of mitochondrial associated genes. Moreover, knockdown of atfs-1 strongly compromised the differentially expressed gene profile. Together these data suggest that increased nuclear activity of HOE-1 preferential impacts expression of mitochondrial genes.
Project description:We previously identified a number of genes which were differentially expressed during mitochondrial stress in an ATFS-1-dependent manner using an atfs-1 loss-of-function mutant allele . To complement the findings from our previous microarray, we compared the transcript profiles from wild-type and atfs-1(et18) gain-of-function worms (which have constitutively active ATFS-1) in the absence of mitochondrial stress. We used microarrays to identify genes regulated by ATFS-1 using a gain-of-function allele of atfs-1.
Project description:To better understand genome coordination and OXPHOS recovery during mitochondrial dysfunction, we examined ATFS-1, a transcription factor that regulates mitochondria-to nuclear communication during the mitochondrial UPR, via ChIP-sequencing. Wildtype worms treated spg-7(RNAi) are analyzed in the presence and absence of ATFS-1 antibody to identify ATFS-1 targets. Individual samples were analyzed. Wildtype worms treated spg-7(RNAi) in the absence of antibody is used as a control.
Project description:ATFS-1 has been shown to regulate transcription of mitochondrial chaperone genes such as mtHsp70/hsp-6 and hsp-60 in response to mitocondrial stress. To identify the entire ATFS-1-mediated response, we compared the transcript profiles from wild-type and atfs-1(tm4525) worms raised in the absence and presence of mitochondrial stress. We used microarrays to identify genes regulated by ZIP-3