title: Structural and functional evolution of the translocator protein (18 kDa).
abstract: Translocator proteins (TSPO) are the products of a family of genes that is evolutionarily conserved from bacteria to humans and expressed in most mammalian tissues and cells. Human TSPO (18 kDa) is expressed at high levels in steroid synthesizing endocrine tissues where it localizes to mitochondria and functions in the first step of steroid formation, the transport of cholesterol into the mitochondria. TSPO expression is elevated in cancerous tissues and during tissue injury, which has lead to the hypothesis that TSPO has roles in apoptosis and the maintenance of mitochondrial integrity. We recently identified a new paralog of Tspo in both the human and mouse. This paralog arose from an ancient gene duplication event before the divergence of the classes aves and mammals, and appears to have specialized tissue-, cell-, and organelle-specific functions. Evidence from the study of TSPO homologs in mammals, bacteria, and plants supports the conclusion that the TSPO family of proteins regulates specialized functions related to oxygen-mediated metabolism. In this review, we provide a comprehensive overview of the divergent function and evolutionary origin of Tspo genes in Bacteria, Archaea, and Eukarya domains.
authors.affiliation: Research Institute of the McGill University Health Centre, Montreal, Quebec H3G 1A4, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Fan
authors.forename: P
authors.initials: P
authors.lastname: Lindemann
authors.forename: M G J
authors.initials: MG
authors.lastname: Feuilloley
authors.forename: V
authors.initials: V
authors.lastname: Papadopoulos
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019843:Archaeal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017124:Conserved Sequence; D019143:Evolution, Molecular; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018079:Receptors, GABA / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D019843:Archaeal Proteins; D001426:Bacterial Proteins; D005656:Fungal Proteins; D010940:Plant Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D018079:Receptors, GABA; C499229:TSPO protein, human; C545441:TSPO2 protein, human