Drosophila Roc1a encodes a RING-H2 protein with a unique function in processing the Hh signal transducer Ci by the SCF E3 ubiquitin ligase.
Substrate specificity of SCF E3 ubiquitin ligases is thought to be determined by the F box protein subunit. Another component of SCF complexes is provided by members of the Roc1/Rbx1/Hrt1 gene family, which encode RING-H2 proteins. Drosophila contains three members of this gene family. We show that Roc1a mutant cells fail to proliferate. Further, while the F box protein Slimb is required for Cubitus interruptus (Ci) and Armadillo/beta-catenin (Arm) proteolysis, Roc1a mutant cells hyperaccumulate Ci but not Arm. This suggests that Slimb and Roc1a function in the same SCF complex to target Ci but that a different RING-H2 protein acts with Slimb to target Arm. Consequently, the identity of the Roc subunit may contribute to the selection of substrates by metazoan SCF complexes.
Noureddine
Maher A
MA
Department of Biology, University of North Carolina, Chapel Hill 27599, USA.
Donaldson
Timothy D
TD
Thacker
Stephen A
SA
Duronio
Robert J
RJ
D000818:Animals; D051186:Armadillo Domain Proteins; D018797:Cell Cycle Proteins / Q000378:metabolism; D002455:Cell Division / Q000235:genetics; D004268:DNA-Binding Proteins / Q000378:metabolism*; D029721:Drosophila Proteins; D066298:In Vitro Techniques; D019476:Insect Proteins / Q000378:metabolism; D007814:Larva; D008025:Ligases / Q000235:genetics*; D008969:Molecular Sequence Data; D050506:Mutant Chimeric Proteins; D009154:Mutation; D011993:Recombinant Fusion Proteins / Q000378:metabolism*; D015398:Signal Transduction; D015534:Trans-Activators; D014157:Transcription Factors / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases
D051186:Armadillo Domain Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D019476:Insect Proteins; D050506:Mutant Chimeric Proteins; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C092937:ci protein, Drosophila; C110233:slmb protein, Drosophila; D044767:Ubiquitin-Protein Ligases; D008025:Ligases