Occurrence of a putative SCF ubiquitin ligase complex in Drosophila.
Many proteins are targeted to proteasome degradation by a family of E3 ubiquitin ligases, termed SCF complexes, that link substrate proteins to an E2 ubiquitin-conjugating enzyme. SCFs are composed of three core proteins-Skp1, Cdc53/Cull, Rbx1/Hrt1-and a substrate specific F-box protein. We have identified in Drosophila melanogaster the closest homologues to the human components of the SCF(betaTrCP) complex and the E2 ubiquitin-conjugating enzyme UbcH5. We show that putative Drosophila SCF core subunits dSkpA and dRbx1 both interact directly with dCu11 and the F-box protein Slmb. We also describe the direct interaction of the UbcH5 related protein UbcD1 with dCul1 and Slmb. In addition, a functional complementation test performed on a Saccharomyces cerevisiae Hrt1p-deficient mutant showed that Drosophila Rbx1 is able to restore the yeast cells viability. Our results suggest that dRbx1, dSkpA, dCullin1, and Slimb proteins are components of a Drosophila SCF complex that functions in combination with the ubiquitin conjugating enzyme UbcD1.
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Instituto de Investigaciones Bioquímicas "Fundación Campomar," Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Patricias Argentinas 435, Buenos Aires, 1405, Argentina.
Muzzopappa
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Silberstein
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Wappner
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D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D044842:Cullin Proteins; D004330:Drosophila / Q000201:enzymology* / Q000235:genetics; D029721:Drosophila Proteins; D017344:Genes, Insect; D005816:Genetic Complementation Test; D006801:Humans; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism*; D046911:Macromolecular Substances; D008954:Models, Biological; D008969:Molecular Sequence Data; D010453:Peptide Synthases / Q000235:genetics / Q000378:metabolism*; D044786:S-Phase Kinase-Associated Proteins; D044843:SKP Cullin F-Box Protein Ligases; D017386:Sequence Homology, Amino Acid; D020798:Two-Hybrid System Techniques; D044767:Ubiquitin-Protein Ligases
D002352:Carrier Proteins; D018797:Cell Cycle Proteins; C100318:Cullin 1; D044842:Cullin Proteins; D029721:Drosophila Proteins; D019476:Insect Proteins; D046911:Macromolecular Substances; D044786:S-Phase Kinase-Associated Proteins; C434749:SkpA protein, Drosophila; C110233:slmb protein, Drosophila; D044843:SKP Cullin F-Box Protein Ligases; D044767:Ubiquitin-Protein Ligases; D010453:Peptide Synthases