Protects against mitochondrial dysfunction during cellular stress, potentially by phosphorylating mitochondrial proteins (By similarity). Plays a role in mitophagy (PubMed:25896323). ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Autophosphorylated. RNAi-mediated knockdown in daf-2, isp-1, or clk-1 mutant backgrounds suppresses their increased lifespan phenotype. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family.