title: Uncoupling proteins (UCP) in unicellular eukaryotes: true UCPs or UCP1-like acting proteins?
abstract: Uncoupling proteins belong to the superfamily of mitochondrial anion carriers. They are apparently present throughout the Eukarya domain in which only some members have an established physiological function, i.e. UCP1 from brown adipose tissue is involved in non-shivering thermogenesis. However, the proteins responsible for the phenotype observed in unicellular organisms have not been characterized. In this report we analyzed functional evidence concerning unicellular UCPs and found that true UCPs are restricted to some taxonomical groups while proteins conferring a UCP1-like phenotype to fungi and most protists are the result of a promiscuous activity exerted by other mitochondrial anion carriers. We describe a possible evolutionary route followed by these proteins by which they acquire this promiscuous mechanism.
authors.affiliation: Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Cidade Universitária, Av Prof Lineu Prestes 748, 05508-000 São Paulo, Brazil. aluevano@iq.usp.br
authors.forename: Luis Alberto
authors.initials: LA
authors.lastname: Luévano-Martínez
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D030562:Databases, Protein; D056890:Eukaryota / Q000378:metabolism*; D019143:Evolution, Molecular; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007473:Ion Channels / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D013045:Species Specificity; D000071256:Uncoupling Protein 1
chemical_list: D005656:Fungal Proteins; D007473:Ion Channels; D024101:Mitochondrial Proteins; D010940:Plant Proteins; D020033:Protein Isoforms; D015800:Protozoan Proteins; D000071256:Uncoupling Protein 1