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) (see TC# 1.R.1). Therefore, StarD7 facilitates phosphatidylcholine (PC) transfer to mitochondria and is essential for mitochondrial homeostasis. A  putative 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 into and/or associated with 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).



Horibata, Y., H. Ando, M. Satou, H. Shimizu, S. Mitsuhashi, Y. Shimizu, M. Itoh, and H. Sugimoto. (2017). Identification of the N-terminal transmembrane domain of StarD7 and its importance for mitochondrial outer membrane localization and phosphatidylcholine transfer. Sci Rep 7: 8793.


TC#NameOrganismal TypeExample

StarD7 of 370 aas and 2 TMSs.  See family description and (Horibata et al. 2017) for a functional description.

StarD7 of Homo sapiens


Uncharacterized StarD7-like phosphatidyl choline transfer protein, PCTP-like protein, of 267 aas and 0 TMSs, containing a START domain. 

UP of Neolamprologus brichardi


Uncharacterized protein of 311 aas and 0 TMSs.

UP of Trypanosoma theileri


Uncharacterized protein of 217 aas

UP of Acinetobacter baumannii


Uncharacterized protein of 244 aas

UP of Turneriella parva


Uncharacterized polyketide cyclase/dehydrase and lipid transport superfamily protein of 294 aas and 2 N-terminal TMSs. 

UP of Arabidopsis thaliana