title: Centrin/Cdc31 is a novel regulator of protein degradation.
abstract: Rad23 is required for efficient protein degradation and performs an important role in nucleotide excision repair. Saccharomyces cerevisiae Rad23, and its human counterpart (hHR23), are present in a complex containing the DNA repair factor Rad4 (termed XPC, for xeroderma pigmentosum group C, in humans). XPC/hHR23 was also reported to bind centrin-2, a member of the superfamily of calcium-binding EF-hand proteins. We report here that yeast centrin, which is encoded by CDC31, is similarly present in a complex with Rad4/Rad23 (called NEF2). The interaction between Cdc31 and Rad23/Rad4 varied by growth phase and reflected oscillations in Cdc31 levels. Strikingly, a cdc31 mutant that formed a weaker interaction with Rad4 showed sensitivity to UV light. Based on the dual function of Rad23, in both DNA repair and protein degradation, we questioned if Cdc31 also participated in protein degradation. We report here that Cdc31 binds the proteasome and multiubiquitinated proteins through its carboxy-terminal EF-hand motifs. Moreover, cdc31 mutants were highly sensitive to drugs that cause protein damage, failed to efficiently degrade proteolytic substrates, and formed altered interactions with the proteasome. These findings reveal for the first time a new role for centrin/Cdc31 in protein degradation.
authors.affiliation: Department of Biochemistry, Robert Wood Johnson Medical School, SPH/RWJMS Room 383, 683 Hoes Lane, Piscataway, NJ 08854, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Chen
authors.forename: Kiran
authors.initials: K
authors.lastname: Madura
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D003001:Cloning, Molecular; D003513:Cycloheximide / Q000494:pharmacology; D004249:DNA Damage; D004271:DNA, Fungal / Q000528:radiation effects; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D005784:Gene Amplification; D020043:Genes, Essential; D005800:Genes, Fungal; D005982:Glutathione Transferase / Q000378:metabolism; D006921:Hygromycin B / Q000494:pharmacology; D009154:Mutation; D010957:Plasmids; D046988:Proteasome Endopeptidase Complex / Q000502:physiology; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D014452:Ubiquitins / Q000378:metabolism*; D014466:Ultraviolet Rays
chemical_list: C083769:CDC31 protein, S cerevisiae; D002135:Calcium-Binding Proteins; D018797:Cell Cycle Proteins; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; C100415:DSK2 protein, S cerevisiae; D011500:Protein Synthesis Inhibitors; C490846:RAD23 protein, S cerevisiae; C493797:Rad4 protein, S cerevisiae; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D014452:Ubiquitins; D006921:Hygromycin B; D003513:Cycloheximide; D005982:Glutathione Transferase; D046988:Proteasome Endopeptidase Complex; D000251:Adenosine Triphosphatases; C084493:RPT1 protein, S cerevisiae