8.A.120. The Mitochondrial StAR-related lipid transfer protein (StAR) Family
StarD7 is anchored onto the outer mitochondrial membrane through its N-terminal TMS, and the C-terminal START domain may extend into the cytoplasm and shuttle phosphatidyl choline between the ER and the outer mitochondrial membrane at ER-mitochondrion contact sites (Horibata et al. 2017). Therefore, StarD7 facilitates phosphatidylcholine (PC) transfer to mitochondria, and is essential for mitochondrial homeostasis. A putative novel TMS, C-terminal to the mitochondria-targeting signal (MTS) sequence at the N-terminus of StarD7 may play an important role. The mature form of StarD7 is integrated and/or associated onto the outer leaflet of the outer mitochondrial membrane. The precursor form of StarD7 is cleaved between Met(76) and Ala(77), and Ala(77) and Ala(78) in the TMS to produce the mature form (Horibata et al. 2017).