title: BTB/POZ domain proteins are putative substrate adaptors for cullin 3 ubiquitin ligases.
abstract: Cullins (CULs) are subunits of a prominent class of RING ubiquitin ligases. Whereas the subunits and substrates of CUL1-associated SCF complexes and CUL2 ubiquitin ligases are well established, they are largely unknown for other cullin family members. We show here that S. pombe CUL3 (Pcu3p) forms a complex with the RING protein Pip1p and all three BTB/POZ domain proteins encoded in the fission yeast genome. The integrity of the BTB/POZ domain, which shows similarity to the cullin binding proteins SKP1 and elongin C, is required for this interaction. Whereas Btb1p and Btb2p are stable proteins, Btb3p is ubiquitylated and degraded in a Pcu3p-dependent manner. Btb3p degradation requires its binding to a conserved N-terminal region of Pcu3p that precisely maps to the equivalent SKP1/F box adaptor binding domain of CUL1. We propose that the BTB/POZ domain defines a recognition motif for the assembly of substrate-specific RING/cullin 3/BTB ubiquitin ligase complexes.
authors.affiliation: Department of Cancer Cell Biology, Harvard School of Public Health, Boston, MA 02115, USA.
authors.forename: Rory
authors.initials: R
authors.lastname: Geyer
authors.forename: Susan
authors.initials: S
authors.lastname: Wee
authors.forename: Scott
authors.initials: S
authors.lastname: Anderson
authors.forename: John
authors.initials: J
authors.lastname: Yates
authors.forename: Dieter A
authors.initials: DA
authors.lastname: Wolf
mesh_terms: D001665:Binding Sites / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D044842:Cullin Proteins; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D044783:F-Box Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008025:Ligases / Q000235:genetics / Q000378:metabolism*; D046911:Macromolecular Substances; D011485:Protein Binding / Q000235:genetics; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary / Q000502:physiology; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D044843:SKP Cullin F-Box Protein Ligases; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D012568:Schizosaccharomyces / Q000201:enzymology*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity; D014157:Transcription Factors; D025801:Ubiquitin / Q000235:genetics / Q000378:metabolism*
chemical_list: C402243:ABTB1 protein, human; C503645:CUL3 protein, human; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D044842:Cullin Proteins; D004268:DNA-Binding Proteins; D044783:F-Box Proteins; D047908:Intracellular Signaling Peptides and Proteins; D046911:Macromolecular Substances; C430457:PAK1IP1 protein, human; D020033:Protein Isoforms; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; D014157:Transcription Factors; D025801:Ubiquitin; D044843:SKP Cullin F-Box Protein Ligases; C120507:SKP1 protein, S cerevisiae; D008025:Ligases