title: Prefoldin, a chaperone that delivers unfolded proteins to cytosolic chaperonin.
abstract: We describe the discovery of a heterohexameric chaperone protein, prefoldin, based on its ability to capture unfolded actin. Prefoldin binds specifically to cytosolic chaperonin (c-cpn) and transfers target proteins to it. Deletion of the gene encoding a prefoldin subunit in S. cerevisiae results in a phenotype similar to those found when c-cpn is mutated, namely impaired functions of the actin and tubulin-based cytoskeleton. Consistent with prefoldin having a general role in chaperonin-mediated folding, we identify homologs in archaea, which have a class II chaperonin but contain neither actin nor tubulin. We show that by directing target proteins to chaperonin, prefoldin promotes folding in an environment in which there are many competing pathways for nonnative proteins.
authors.affiliation: Department of Biochemistry, New York University Medical Center, New York 10016, USA.
authors.forename: I E
authors.initials: IE
authors.lastname: Vainberg
authors.forename: S A
authors.initials: SA
authors.lastname: Lewis
authors.forename: H
authors.initials: H
authors.lastname: Rommelaere
authors.forename: C
authors.initials: C
authors.lastname: Ampe
authors.forename: J
authors.initials: J
authors.lastname: Vandekerckhove
authors.forename: H L
authors.initials: HL
authors.lastname: Klein
authors.forename: N J
authors.initials: NJ
authors.lastname: Cowan
mesh_terms: D000199:Actins / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001105:Archaea / Q000235:genetics; D001692:Biological Transport; D018834:Chaperonin 60 / Q000378:metabolism; D056404:Chaperonin Containing TCP-1; D018833:Chaperonins / Q000378:metabolism*; D005057:Eukaryotic Cells; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding; D011489:Protein Denaturation; D017510:Protein Folding; D011817:Rabbits; D012441:Saccharomyces cerevisiae; D017386:Sequence Homology, Amino Acid
chemical_list: D000199:Actins; D018834:Chaperonin 60; D018832:Molecular Chaperones; C112806:prefoldin; D056404:Chaperonin Containing TCP-1; D018833:Chaperonins