The function of STARD7 (StAR related lipid transfer domain containing 7, ENSG00000084090) is as follows. Mediates non-vesicular transfer of phosphatidylcholine to mitochondria, thereby maintaining mitochondrial membrane lipid composition, cristae organization, and respiratory function across diverse tissues. {ECO:0000269|PubMed:20042613, ECO:0000269|PubMed:28401922, ECO:0000269|PubMed:28821867, ECO:0000269|PubMed:29301859, ECO:0000269|PubMed:32071354, ECO:0000269|PubMed:34416390}. [StAR-related lipid transfer protein 7, mitochondrial]: Transfers phosphatidylcholine (PC) from the endoplasmic reticulum to the mitochondrial outer membrane at ER-mitochondria contact sites, thereby maintaining mitochondrial PC content, respiratory complex stability and mitochondrial cristae morphology. . [StAR-related lipid transfer protein 7, mature]: Transfers phosphatidylcholine (PC) between the mitochondrial outer and inner membranes, contributing to mitochondrial lipid homeostasis. The mature cytosolic and intermembrane space forms of STARD7 mediate non-vesicular PC transport by transiently associating with mitochondrial membranes. Required for normal cristae architecture and optimal activity of the respiratory chain (PubMed:29301859). Mediates intracellular distribution of coenzyme Q (ubiquinone), the intermembrane space form supports mitochondrial coenzyme Q biosynthesis and the cytosolic form transfers coenzyme Q to extramitochondrial membranes, enhancing antioxidant protection and limiting ferroptosis sensitivity (PubMed:36658222). {ECO:0000269|PubMed:29301859, ECO:0000269|PubMed:36658222}.