A subfamily of stress proteins facilitates translocation of secretory and mitochondrial precursor polypeptides

Deshaies, Raymond J.; Koch, B; Werner‐Washburne, Margaret; Craig, Elizabeth A.; Schekman, Randy

doi:10.1038/332800a0

Cited by 1,470 publications

(792 citation statements)

References 49 publications

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“…They serve important functions when the microorganism adapts to environmental changes and their synthesis markedly increases when the cell is exposed to elevated temperatures or to other stress factors, such as oxygen radicals or ethanol. These proteins are believed to function intracellularly as molecular chaperones involved in protein folding, unfolding and assembly; in eucaryotes more precisely in protein unfolding before secretion [153]. The crystal structure of GroES from M. leprae has recently been elucidated and revealed a heptamer configuration with the form of a highly charged dome [154].…”

Section: Culture Filtrate Proteinsmentioning

confidence: 99%

Host Responses and Antigens Involved in Protective Immunity to Mycobacterium tuberculosis

1997

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Andersen P. Host Responses and Antigens Involved in Protective Immunity to Mycobacterium tuberculosis. Scand J Immunol 1997;45:115-131 Tuberculosis (TB) is the largest single infectious cause of human mortality. The incidence of TB has remained high in most of the developing world and the disease has recently re-emerged as a public health problem in industrialized countries. The development of a new improved TB vaccine is a highly prioritized international research area, which has been further stimulated by the appearance of multi-drug resistant strains of Mycobacterium tuberculosis. The present status of the attempts to characterize the protective immune response to TB will be reviewed with special emphasis on recent progress in the identification and characterization of target molecules recognized by protective cells. This paper will focus on proteins released from live bacteria and discuss their role in the host-pathogen interaction and the ongoing attempts to use these molecules in TB subunit vaccines.

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Section: Culture Filtrate Proteinsmentioning

confidence: 99%

Host Responses and Antigens Involved in Protective Immunity to Mycobacterium tuberculosis

1997

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“…Recently, it has been reported that an enzymatic unfolding activity is necessary for the denaturation of native proteins that are to be translocated across microsomal [11,12] and mitochondrial [11,19] membranes. This activity has been attributed to a member(s) of the 70 kDa heat shock protein family (hsp 70).…”

Section: Resultsmentioning

confidence: 99%

“…Although this process is well characterized [1][2][3], the machinery involved is not. In addition to the mitochondrial receptor/translocation apparatus and processing proteases, there is evidence suggesting that soluble cytosolic proteins are required as well [4][5][6][7][8][9][10][11]. It may be that an import-competent conformation effected by soluble proteins results in the enhanced translocation of proteins across both microsomal [11][12][13], mitochondrial [11] and bacterial cell membranes [14,15].…”

Section: Introductionmentioning

confidence: 99%

“…In addition to the mitochondrial receptor/translocation apparatus and processing proteases, there is evidence suggesting that soluble cytosolic proteins are required as well [4][5][6][7][8][9][10][11]. It may be that an import-competent conformation effected by soluble proteins results in the enhanced translocation of proteins across both microsomal [11][12][13], mitochondrial [11] and bacterial cell membranes [14,15]. A recent report has shown that at least two independent soluble activities (hsp Abbreviations: CCCP, carbonylcyanide-m-chlophenyl hydrazone; HSF, heat-stable factor; NEM, N-ethylmaleimide; pOCT, precursor to ornithine carbamyltransferase; pO-DHFR, dihydrofolate reductase fused to the signal sequence of pOCT 70 and an NEM-sensitive factor) are important for efficient import of mitochondrial precursors [16].…”

Section: Introductionmentioning

confidence: 99%

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Import of a mutant mitochondrial precursor fails to respond to stimulation by a cytosolic factor

Randall

Shore

1989

FEBS Letters

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Import of the precursor to ornithine carbamyltransferase is stimulated by a partially‐purified, NEM‐sensitive soluble factor from rabbit reticulocyte lysate. A mutant in which the carboxy‐terminal 73 amino acids were deleted, had a sharply reduced response to this factor. The NEM‐sensitive, import‐stimulating factor interacts with the surface of mitochondria in the absence of precursor protein. Thus reticulocyte lysate contains an NEM‐sensitive, import stimulating factor which interacts both with the surface of mitochondria and whose activity appears to be dependent upon the structure of the mature portion of the precursor.

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“…Such a function is illustrated by the reactivation of heat-denatured and aggregated E. coli RNA polymerase in the presence of ATP and DnaK protein, the bacterial hsp70 (Skowira eta/., 1990). In cells grown under normal conditions, constitutive hsp70s have been shown to bind protein precursors and to maintain them in a proper conformation during protein transport and secretion (Deshaies et a/., 1988). For example, genetical and biochemical evidence have demonstrated that hsp70s are involved in the transport of proteins into yeast mitochondria (Kang et a/., 1990).…”

Section: Introductionmentioning

confidence: 99%

Molecular characterization of a 70 kDa heat‐shock protein of bean mitochondria

et al. 1993

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SummaryA bean cDNA clone that specifies a 70 kDa heat-shock protein (hsp70) has been isolated and sequenced. The nucleotide sequence analysis shows that the cDNA could encode a 72 kDa protein that is highly related to prokaryotic and mitochondrial members of the hsp7O family. The predicted protein was found to contain an amino-terminal extension typical of transit sequences. The in vitro transcription/translation product of the cDNA behaved as a 72 kDa polypeptide as predicted from the longest open reading frame. This polypeptide could be imported into isolated mitochondria and recovered as a 68 kDa product. The imported protein is identical in size to a mitochondrial protein that cross-reacts with hsp70-specific antibodies. The import data and Western blot analysis suggest that the cDNA clone encodes a mitochondrial member of the hsp70 family. Electrophoretic and immunoblot analysis reveal that the protein is loosely associated to the mitochondrial envelope and also exists as discrete soluble protein aggregates of about 270 and 420 kDa. Hsp7O of bean mitochondria can be in vitro phosphorylated on threonine residues in a calcium-dependent manner, and the modified protein was detected as an oligomer of about 160 kDa only. The data are discussed with respect to the chaperone function of hsp7O in mitochondria.

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A subfamily of stress proteins facilitates translocation of secretory and mitochondrial precursor polypeptides

Cited by 1,470 publications

References 49 publications

Host Responses and Antigens Involved in Protective Immunity to Mycobacterium tuberculosis

Host Responses and Antigens Involved in Protective Immunity to Mycobacterium tuberculosis

Import of a mutant mitochondrial precursor fails to respond to stimulation by a cytosolic factor

Molecular characterization of a 70 kDa heat‐shock protein of bean mitochondria

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