title: A brief history of the search for the protein(s) involved in the acute regulation of steroidogenesis.
abstract: The synthesis of steroid hormones occurs in specific cells and tissues in the body in response to trophic hormones and other signals. In order to synthesize steroids de novo, cholesterol, the precursor of all steroid hormones, must be mobilized from cellular stores to the inner mitochondrial membrane (IMM) to be converted into the first steroid formed, pregnenolone. This delivery of cholesterol to the IMM is the rate-limiting step in this process, and has long been known to require the rapid synthesis of a new protein(s) in response to stimulation. Although several possibilities for this protein have arisen over the past few decades, most of the recent attention to fill this role has centered on the candidacies of the proteins the Translocator Protein (TSPO) and the Steroidogenic Acute Regulatory Protein (StAR). In this review, the process of regulating steroidogenesis is briefly described, the characteristics of the candidate proteins and the data supporting their candidacies summarized, and some recent findings that propose a serious challenge for the role of TSPO in this process are discussed.
authors.affiliation: Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA. Electronic address: doug.stocco@ttuhsc.edu.
authors.forename: Douglas M
authors.initials: DM
authors.lastname: Stocco
authors.affiliation: Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Amy H
authors.initials: AH
authors.lastname: Zhao
authors.affiliation: Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Lan N
authors.initials: LN
authors.lastname: Tu
authors.affiliation: Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Kanako
authors.initials: K
authors.lastname: Morohaku
authors.affiliation: Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Vimal
authors.initials: V
authors.lastname: Selvaraj
mesh_terms: D000818:Animals; D053898:Biosynthetic Pathways; D002784:Cholesterol / Q000378:metabolism; D006801:Humans; D010750:Phosphoproteins / Q000378:metabolism; D011506:Proteins / Q000378:metabolism*; D011963:Receptors, GABA-A / Q000378:metabolism; D013256:Steroids / Q000096:biosynthesis*; D000098682:Steroidogenic Acute Regulatory Protein
chemical_list: D010750:Phosphoproteins; D011506:Proteins; D011963:Receptors, GABA-A; D013256:Steroids; D000098682:Steroidogenic Acute Regulatory Protein; D002784:Cholesterol
keywords: Conditional knockout; Global knockout; Mitochondria; Steroidogenesis; Steroidogenic Acute Regulatory Protein (StAR); Translocator Protein (TSPO)