title: Direct binding of ubiquitin conjugates by the mammalian p97 adaptor complexes, p47 and Ufd1-Npl4.
abstract: The multiple functions of the p97/Cdc48p ATPase can be explained largely by adaptors that link its activity to different cellular pathways, but how these adaptors recognize different substrates is unclear. Here we present evidence that the mammalian adaptors, p47 and Ufd1-Npl4, both bind ubiquitin conjugates directly and so link p97 to ubiquitylated substrates. In the case of Ufd1-Npl4, which is involved in endoplasmic reticulum (ER)-associated degradation and nuclear envelope reassembly, binding to ubiquitin is mediated through a putative zinc finger in Npl4. This novel domain (NZF) is conserved in metazoa and is both present and functional in other proteins. In the case of p47, which is involved in the reassembly of the ER, the nuclear envelope and the Golgi apparatus, binding is mediated by a UBA domain. Unlike Ufd1-Npl4, it binds ubiquitin only when complexed with p97, and binds mono- rather than polyubiquitin conjugates. The UBA domain is required for the function of p47 in mitotic Golgi reassembly. Together, these data suggest that ubiquitin recognition is a common feature of p97-mediated reactions.
authors.affiliation: Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, SHM, C441, PO Box 208002, New Haven, CT 06520-8002, USA. hemmo.meyer@yale.edu
authors.forename: Hemmo H
authors.initials: HH
authors.lastname: Meyer
authors.forename: Yanzhuang
authors.initials: Y
authors.lastname: Wang
authors.forename: Graham
authors.initials: G
authors.lastname: Warren
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport / Q000737:chemistry / Q000378:metabolism*; D000251:Adenosine Triphosphatases; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D018797:Cell Cycle Proteins / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism; D008322:Mammals; D008969:Molecular Sequence Data; D011485:Protein Binding; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D055765:Shc Signaling Adaptor Proteins; D025801:Ubiquitin / Q000378:metabolism*; D000074405:Valosin Containing Protein; D016335:Zinc Fingers
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D018797:Cell Cycle Proteins; D011994:Recombinant Proteins; D055765:Shc Signaling Adaptor Proteins; D025801:Ubiquitin; D000251:Adenosine Triphosphatases; D000074405:Valosin Containing Protein