title: Roles of the N domain of the AAA+ Lon protease in substrate recognition, allosteric regulation and chaperone activity.
abstract: Degron binding regulates the activities of the AAA+ Lon protease in addition to targeting proteins for degradation. The sul20 degron from the cell-division inhibitor SulA is shown here to bind to the N domain of Escherichia coli Lon, and the recognition site is identified by cross-linking and scanning for mutations that prevent sul20-peptide binding. These N-domain mutations limit the rates of proteolysis of model sul20-tagged substrates and ATP hydrolysis by an allosteric mechanism. Lon inactivation of SulA in vivo requires binding to the N domain and robust ATP hydrolysis but does not require degradation or translocation into the proteolytic chamber. Lon-mediated relief of proteotoxic stress and protein aggregation in vivo can also occur without degradation but is not dependent on robust ATP hydrolysis. In combination, these results demonstrate that Lon can function as a protease or a chaperone and reveal that some of its ATP-dependent biological activities do not require translocation.
authors.affiliation: Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Wohlever
authors.forename: Tania A
authors.initials: TA
authors.lastname: Baker
authors.forename: Robert T
authors.initials: RT
authors.lastname: Sauer
mesh_terms: D000074183:ATPases Associated with Diverse Cellular Activities; D000251:Adenosine Triphosphatases; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000494:Allosteric Regulation; D001665:Binding Sites; D049071:Endopeptidase Clp; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D018832:Molecular Chaperones / Q000378:metabolism*; D009154:Mutation; D049070:Protease La / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D059748:Proteolysis; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D029968:Escherichia coli Proteins; D018832:Molecular Chaperones; D011993:Recombinant Fusion Proteins; C053139:sulA protein, E coli; D000255:Adenosine Triphosphate; C483567:Lon protein, E coli; D049070:Protease La; D049071:Endopeptidase Clp; D000251:Adenosine Triphosphatases; C088072:ClpX protein, E coli; D000074183:ATPases Associated with Diverse Cellular Activities