title: Hierarchical binding of cofactors to the AAA ATPase p97.
abstract: The hexameric AAA ATPase p97 is involved in several human proteinopathies and mediates ubiquitin-dependent protein degradation among other essential cellular processes. Via its N-terminal domain (N domain), p97 interacts with multiple regulatory cofactors including the UFD1/NPL4 heterodimer and members of the "ubiquitin regulatory X" (UBX) domain protein family; however, the principles governing cofactor selectivity remain to be deciphered. Our crystal structure of the FAS-associated factor 1 (FAF1)UBX domain in complex with the p97N domain reveals that the signature Phe-Pro-Arg motif known to be crucial for interactions of UBX domains with p97 adopts a cis-proline configuration, in contrast to a cis-trans mixture we derive for the isolated FAF1UBX domain. Biochemical studies confirm that binding critically depends on a proline at this position. Furthermore, we observe that the UBX proteins FAF1 and UBXD7 only bind to p97-UFD1/NPL4, but not free p97, thus demonstrating for the first time a hierarchy in p97-cofactor interactions.
authors.affiliation: Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Josef-Schneider-Str. 2, 97080 Würzburg, Germany. petra.haenzelmann@virchow.uni-wuerzburg.de
authors.forename: Petra
authors.initials: P
authors.lastname: Hänzelmann
authors.forename: Alexander
authors.initials: A
authors.lastname: Buchberger
authors.forename: Hermann
authors.initials: H
authors.lastname: Schindelin
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry*; D033942:Adaptor Proteins, Vesicular Transport; D000251:Adenosine Triphosphatases / Q000737:chemistry*; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D051017:Apoptosis Regulatory Proteins; D002151:Calorimetry; D002352:Carrier Proteins / Q000737:chemistry; D002850:Chromatography, Gel; D003067:Coenzymes / Q000737:chemistry*; D017124:Conserved Sequence; D018360:Crystallography, X-Ray; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry*; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry; D013499:Surface Properties; D017186:Titrimetry; D025801:Ubiquitin / Q000737:chemistry; D057149:Ubiquitinated Proteins / Q000737:chemistry
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D051017:Apoptosis Regulatory Proteins; D002352:Carrier Proteins; D003067:Coenzymes; C490780:FAF1 protein, human; D047908:Intracellular Signaling Peptides and Proteins; C514112:NPLOC4 protein, human; D009687:Nuclear Proteins; D011506:Proteins; C531895:UBXN7 protein, human; C491497:UFD1 protein, human; D025801:Ubiquitin; D057149:Ubiquitinated Proteins; D000251:Adenosine Triphosphatases; C404942:p97 ATPase