title: HspBP1, a homologue of the yeast Fes1 and Sls1 proteins, is an Hsc70 nucleotide exchange factor.
abstract: The yeast FES1 and SLS1 genes encode conserved nucleotide exchange factors that act on the cytoplasmic and endoplasmic reticulum luminal Hsp70s, Ssa1p and BiP, respectively. We report here that mammalian HspBP1 is homologous to Fes1p and that HspBP1 promotes nucleotide dissociation from both Ssa1p and mammalian Hsc70. In contrast, Fes1p inefficiently strips nucleotide from mammalian Hsc70, and unlike HspBP1 does not inhibit chaperone-mediated protein refolding in vitro. Together, our data indicate that HspBP1 is a member of this new class of nucleotide exchange factors that exhibit varying degrees of compartment and species specificity.
authors.affiliation: Department of Biological Sciences, 274 Crawford Hall, University of Pittsburgh, Pittsburgh, PA 15260, USA.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Kabani
authors.forename: Catherine
authors.initials: C
authors.lastname: McLellan
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Raynes
authors.forename: Vince
authors.initials: V
authors.lastname: Guerriero
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Brodsky
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005656:Fungal Proteins / Q000235:genetics / Q000494:pharmacology; D050883:HSC70 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism* / Q000494:pharmacology; D007700:Kinetics; D008156:Luciferases / Q000737:chemistry; D017510:Protein Folding; D029701:Saccharomyces cerevisiae Proteins; D017385:Sequence Homology
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D004791:Enzyme Inhibitors; D005656:Fungal Proteins; D050883:HSC70 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; C116331:HSPBP1 protein, human; D029701:Saccharomyces cerevisiae Proteins; D000255:Adenosine Triphosphate; D008156:Luciferases; D000251:Adenosine Triphosphatases; C095973:SSA1 protein, S cerevisiae