The mitochondrial chaperonin hsp60 is required for its own assembly

  title={The mitochondrial chaperonin hsp60 is required for its own assembly},
  author={Ming Yuan Cheng and F. Ulrich Hartl and Arthur L. Norwich},
HEATSHOCK protein 60 (hsp60) in the matrix of mitochondria is essential for the folding and assembly of newly imported proteins1. Hsp60 belongs to a class of structurally related chaperonins found in organelles of endosymbiotic origin and in the bacterial cytosol2–9. Hsp60 monomers form a complex arranged as two stacked 7-mer rings6. This 14-mer complex binds unfolded proteins at its surface, then seems to catalyse their folding in an ATP-dependent process10. The question arises as to how such… Expand
The human mitochondrial Hsp60 in the APO conformation forms a stable tetradecameric complex
Bacterial expression and purification of fully assembled human Hsp60 and Hsp10 recombinant proteins are reported and it is revealed that Hsp50 forms a stable tetradecameric double-ring conformation in the absence of co-chaperonin and nucleotide and the presence of a non-native substrate initiates ATP-hydrolysis within the Hsp 60/10 chaperon in to commence protein folding. Expand
Two cofactors and cytoplasmic chaperonin are required for the folding of alpha- and beta-tubulin
Though the chaperonins that mediate folding in prokaryotes, mitochondria, and chloroplasts have been relatively well characterized, the folding of proteins in the eukaryotic cytosol is much less wellExpand
Heat shock proteins: molecular chaperones of protein biogenesis
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Single-Ring Intermediates Are Essential for Some Chaperonins
A brief review of chaperonins that can form double- and single-ring conformational intermediates in their protein-folding catalytic pathway is presented and of special interest are the ϕ-EL and OBP chaper onins which demonstrate features of both group I and II chaperOnins in addition to their ability to function via single- ring intermediates. Expand
Loss of Mitochondrial hsp6O Function: Nonequivalent Effects
We have created yeast strains in which the mitochondrial chaperonin, hsp6O, can be either physically depleted or functionally inactivated. Cells completely depleted of hsp6O stop growing but retainExpand
Identification of in vivo substrates of the yeast mitochondrial chaperonins reveals overlapping but non‐identical requirement for hsp60 and hsp10
It is suggested that homologous substrate proteins have differential chaperonin requirements, indicating that hsp60 and hsp10 do not always act as a single functional unit in vivo. Expand
Antifolding activity of hsp60 couples protein import into the mitochondrial matrix with export to the intermembrane space
Hsp60 combines two activities: catalysis of folding of proteins destined for the matrix, and maintaining proteins in an unfolded state to facilitate their channeling between the machineries for import and export across the inner membrane. Expand
HSPD 1 ( heat shock 60 kDa protein 1 )
The HSP60 consists of 573 amino acids corresponding to a molecular weight of 61.05 kDa. The HSP60 proteins are ubiquitous abundant proteins of eubacterial genomes and also known as the Chaperonin.Expand
Molecular chaperones and the biogenesis of mitochondria and peroxisomes
Those aspects of mitochondrial biogenesis that have developed rapidly during the last few years, such as the requirement of molecular chaperones, are stressed in order to stimulate further parallel investigations aimed to understand the origin, biochemistry, molecular biology and pathology of peroxisomes. Expand
Mitochondrial Heat Shock Protein (Hsp) 70 and Hsp10 Cooperate in the Formation of Hsp60 Complexes*
It is concluded that coupling to Hsp10 recruits mtHsp70 to mediate the biogenesis of the heptameric Hsp60 rings. Expand