The human steroidogenic acute regulatory (StAR) gene is expressed in the urogenital system and encodes a mitochondrial polypeptide.
The first enzymatic step in the biosynthesis of steroid hormones occurs in the mitochondrial inner membrane and is dependent on the mobilization of cholesterol from cellular stores. We report on the isolation of a human cDNA which encodes a mitochondrial protein called steroidogenic acute regulatory (StAR) protein, implicated in transport of cholesterol into mitochondria. Nucleotide and predicted amino acid sequence analyses indicate that the human and murine polypeptides are highly conserved, sharing 87% identity with an overall homology of 92%. Analysis of the distribution of StAR mRNA transcripts in human tissues by Northern blotting reveals several mRNA species, the most abundant of which is a 1.8 kb mRNA transcript present in testes, ovaries and kidneys. Using in vitro translated protein, we demonstrate that the StAR gene product can be efficiently imported into exogenously added mitochondria.
Gradi
A
A
Department of Biochemistry, McGill University, Montreal, Quebec, Canada.
Tang-Wai
R
R
McBride
H M
HM
Chu
L L
LL
Shore
G C
GC
Pelletier
J
J
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001692:Biological Transport; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D002460:Cell Line; D002784:Cholesterol / Q000378:metabolism; D003001:Cloning, Molecular; D005260:Female; D015870:Gene Expression / Q000235:genetics; D006801:Humans; D008297:Male; D008928:Mitochondria / Q000737:chemistry* / Q000378:metabolism; D008969:Molecular Sequence Data; D009369:Neoplasms / Q000737:chemistry / Q000235:genetics; D010455:Peptides / Q000737:chemistry; D010750:Phosphoproteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D016415:Sequence Alignment; D014357:Trypsin / Q000378:metabolism; D014407:Tumor Cells, Cultured; D014566:Urogenital System / Q000378:metabolism*; D000098682:Steroidogenic Acute Regulatory Protein
D010455:Peptides; D010750:Phosphoproteins; D000098682:Steroidogenic Acute Regulatory Protein; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D002784:Cholesterol; D014357:Trypsin