Probable transcription factor that acts during mitochondrial stress by activating the mitochondrial unfolded protein response (mtUPR) (PubMed:17925224, PubMed:30642431). Required during mitochondrial stress for the activation of genes involved in the mtUPR, in concert with histone deacetylase hda-1 (PubMed:32934238). May play a role in modulating the decline in protein homeostasis associated with normal aging (PubMed:32934238). Required for embryonic development and maintenance of mitochondrial morphology (PubMed:17925224). Interacts with ubiquitin-like protein ubl-5; the interaction occurs in a mitochondrial stress-dependent manner (PubMed:17925224). Interacts with lin-40; probably associates with a NuRD (Nucleosome Remodeling and Deacetylase) complex via lin-40 (PubMed:32789178). Interacts with histone deacetylase hda-1 (PubMed:32934238). Upon mitochondrial stress translocates from cytosol into the nucleus. Widely expressed in embryos, but particularly in intestinal precursor cells (at protein level). Sumoylated at Lys-327; sumoylation is required for cytosolic localization (PubMed:30642431). May be desumoylated by ulp-4 (PubMed:30642431). RNAi-mediated knockdown inhibits expression of hsp-60 when adults are exposed to conditions causing mitochondrial unfolded protein stress (PubMed:17925224). Causes abnormal mitochondrial morphology (PubMed:17925224). Drastically reduces the protein level of hda-1, possibly via ubiquitin-mediated degradation (PubMed:32934238). Under conditions of mitochondrial stress, partially suppresses nuclear accumulation of lin-40 and lin-53 (PubMed:32789178).