Protein phosphatase that plays an essential role in mitochondrial metabolism and biogenesis (PubMed:30267671). Positively regulates biosynthesis of the ubiquinone, coenzyme Q (PubMed:30267671). Dephosphorylates the ubiquinone biosynthesis protein COQ7 which is likely to lead to its activation (PubMed:30267671). Serves as a crucial sensor for mitophagy, though the underlying mechanism remains ambiguous (By similarity). May dephosphorylate BNIP3 and NIX and thereby directly regulates mitophagy receptor function and stability (By similarity). Alternatively, promotes SCF-FBXL4-dependent ubiquitination and degradation of BNIP3 and NIX independently of its catalytic activity to restrain mitophagy (PubMed:38992176). {ECO:0000250|UniProtKB:Q6NVE9, ECO:0000269|PubMed:30267671, ECO:0000269|PubMed:38992176}. This is the function of PPTC7 (protein phosphatase targeting COQ7, ENSG00000196850).