title: Substrate threading through the central pore of the Hsp104 chaperone as a common mechanism for protein disaggregation and prion propagation.
abstract: The oligomeric AAA+ chaperone Hsp104 is essential for thermotolerance development and prion propagation in yeast. Thermotolerance relies on the ability of Hsp104 to cooperate with the Hsp70 chaperone system in the reactivation of heat-aggregated proteins. Prion propagation requires the Hsp104-dependent fragmentation of prion fibrils to create infectious seeds. It remained elusive whether both processes rely on common or different activities of Hsp104. Specifically, protein reactivation has been suggested to require a substrate threading activity of Hsp104 whereas fibril fragmentation may be mediated by a crowbar activity. Here we engineered an Hsp104 variant, HAP, which cooperates with the bacterial peptidase ClpP to form a novel proteolytic system. HAP threads aggregated model substrates as well as the yeast prion Sup35 through its central pore into associated ClpP. HAP variants that harbour a reduced threading activity were affected in both protein disaggregation and prion propagation, demonstrating that substrate threading represents the common mechanism for the processing of both substrate classes.
authors.affiliation: Universität Heidelberg, Zentrum fuer Molekulare Biologie Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, Heidelberg D-69120, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Tessarz
authors.forename: Axel
authors.initials: A
authors.lastname: Mogk
authors.forename: Bernd
authors.initials: B
authors.lastname: Bukau
mesh_terms: D000595:Amino Acid Sequence; D002364:Caseins / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018832:Molecular Chaperones / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D011328:Prions / Q000378:metabolism*; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
chemical_list: D002364:Caseins; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D011328:Prions; D029701:Saccharomyces cerevisiae Proteins; C070972:HsP104 protein, S cerevisiae