StAR Related Lipid Transfer Domain Containing Protein 3 (STARD3)

STARD3 encodes a member of a subfamily of lipid trafficking proteins that are characterized by a C-terminal steroidogenic acute regulatory domain and an N-terminal metastatic lymph node 64 domain. The encoded protein localizes to the membranes of late endosomes and may be involved in exporting cholesterol. Alternative splicing results in multiple transcript variants.Sequence analysis predicted that the 445-amino acid protein, which is 33% identical to STAR, contains an N-terminal hydrophobic, helical transmembrane region and a C-terminal STAR homology domain characterized by a WX(4)DLKGXLP protein signature. Northern blot analysis indicated high levels of a 2.1-kb transcript that was coexpressed with ERBB2 in 15% of invasive primary breast carcinomas and in 43% of breast cancer metastases tested.