TY - JOUR

T1 - The Ubx2 and Ubx3 cofactors direct Cdc48 activity to proteolytic and nonproteolytic ubiquitin-dependent processes.

AU - Hartmann-Petersen, Rasmus

AU - Wallace, Mairi

AU - Hofmann, Kay

AU - Koch, Grete

AU - Johnsen, Anders H

AU - Hendil, Klavs B

AU - Gordon, Colin

N1 - Keywords: Adenosine Triphosphatases; Amino Acid Sequence; Cell Cycle Proteins; Flow Cytometry; Membrane Fusion; Molecular Sequence Data; Mutation; Peptide Hydrolases; Phenotype; Plasmids; Proteasome Endopeptidase Complex; Schizosaccharomyces; Schizosaccharomyces pombe Proteins; Sequence Alignment; Two-Hybrid System Techniques; Ubiquitins

PY - 2004

Y1 - 2004

N2 - Valosin-containing protein, VCP/p97 or Cdc48, is a eukaryotic ATPase involved in membrane fusion, protein transport, and protein degradation. We describe two proteins, Ubx2 and Ubx3, which interact with Cdc48 in fission yeast. Ubx3 is the ortholog of p47/Shp1, a previously described Cdc48 cofactor involved in membrane fusion, whereas Ubx2 is a novel protein. Cdc48 binds the UBX domains present in both Ubx2 and Ubx3, indicating that this domain is a general Cdc48-interacting module. Ubx2 and Ubx3 also interact with ubiquitin chains. Disruption of the ubx3(+)-gene causes both temperature and canavanine sensitivity and stabilizes some ubiquitin-protein conjugates including the CDK inhibitor Rum1, but not a model substrate of the ER-degradation pathway. Moreover the ubx3 null displays synthetic lethality with a pus1 null mutant, a multiubiquitin binding subunit of the 26S proteasome. In contrast, the ubx2 null mutant did not display any obvious protein-degradation phenotype. In conclusion Ubx3/p47 is not, as previously thought, only important for membrane fusion; it's also important for the specific degradation of a subset of cell proteins. Our genetic analyses revealed that Ubx3/p47 functionally parallels a substrate receptor of the 26S proteasome, Pus1/Rpn10, indicating that the Cdc48-Ubx3 complex is involved in delivering substrates to the 26S proteasome.

AB - Valosin-containing protein, VCP/p97 or Cdc48, is a eukaryotic ATPase involved in membrane fusion, protein transport, and protein degradation. We describe two proteins, Ubx2 and Ubx3, which interact with Cdc48 in fission yeast. Ubx3 is the ortholog of p47/Shp1, a previously described Cdc48 cofactor involved in membrane fusion, whereas Ubx2 is a novel protein. Cdc48 binds the UBX domains present in both Ubx2 and Ubx3, indicating that this domain is a general Cdc48-interacting module. Ubx2 and Ubx3 also interact with ubiquitin chains. Disruption of the ubx3(+)-gene causes both temperature and canavanine sensitivity and stabilizes some ubiquitin-protein conjugates including the CDK inhibitor Rum1, but not a model substrate of the ER-degradation pathway. Moreover the ubx3 null displays synthetic lethality with a pus1 null mutant, a multiubiquitin binding subunit of the 26S proteasome. In contrast, the ubx2 null mutant did not display any obvious protein-degradation phenotype. In conclusion Ubx3/p47 is not, as previously thought, only important for membrane fusion; it's also important for the specific degradation of a subset of cell proteins. Our genetic analyses revealed that Ubx3/p47 functionally parallels a substrate receptor of the 26S proteasome, Pus1/Rpn10, indicating that the Cdc48-Ubx3 complex is involved in delivering substrates to the 26S proteasome.

U2 - 10.1016/j.cub.2004.04.029

DO - 10.1016/j.cub.2004.04.029

M3 - Journal article

C2 - 15120077

VL - 14

SP - 824

EP - 828

JO - Current Biology

JF - Current Biology

SN - 0960-9822

IS - 9

ER -