Import of phosphatidylserine to and export of phosphatidylethanolamine molecular species from mitochondria

► Mass spectrometry was used to study PE and PS trafficking to and from mitochondria. ► The acyl chains have a major effect on translocation of both PS and PE. ► KD of Mitofusin 2 and Mitostatin had no effect on PS translocation to mitochondria. ► Inhibition of PS synthesis by KD of PS synthase 1 markedly inhibited PS translocation. ► The CDP-EA and PSD pathways both contribute significantly to the PE pools of IMM and ER.