Transient association of newly synthesized unfolded proteins with the heat-shock GroEL protein

Bochkareva, Elena; Lissin, Nikolai; Girshovich, A.S.

doi:10.1038/336254a0

Cited by 402 publications

(194 citation statements)

References 23 publications

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“…ATP is apparently not necessary for association of the precursor proteins with GroEL. The complexes dissociate after adding ATP (BOCHKAREVA et al 1988). Since the interaction of GroEL and GroES was only observed in the presence of ATP (CHANDRASEKHAR et al 1986), a role of the GroES protein in the release of GroEL-associated proteins was assumed (KUSUKAWAet al 1989).…”

Section: Translocation Of Proteins Across Membranesmentioning

confidence: 99%

“…Evidence for interaction of GroEL with newly synthesized proteins came from photo-cross-linking experiments (BOCHKAREVA et al 1988). After such cross-linking newly synthesized, plasmid-encoded secretory ^-lactamase (and plasmid-encoded chloramphenicol acetyltransferase) sedimented during ultracentrifugation as a 20S particle.…”

Section: Translocation Of Proteins Across Membranesmentioning

confidence: 99%

“…The same subset of E. coli heat shock proteins seems to be involved in some of these processes, namely DnaK, DnaJ, and GrpE, which are all essential for bacterial growth. DnaK, several other proteins have been suggested to exert such a chaperone function in E. coli, namely SecB, trigger factor, and GroEL (COLLIER et al 1988;CROOKE and WICKNER 1987;CROOKE et al 1988;BOCHKAREVA et al 1988). …”

Section: Dnak-the Prokaryotic Homologuementioning

confidence: 99%

See 2 more Smart Citations

Heat Shock Proteins hsp60 and hsp70: Their Roles in Folding, Assembly and Membrane Translocation of Proteins

Langer¹,

Neupert²

1991

Current Topics in Microbiology and Immunology

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Section: Translocation Of Proteins Across Membranesmentioning

confidence: 99%

Section: Translocation Of Proteins Across Membranesmentioning

confidence: 99%

Section: Dnak-the Prokaryotic Homologuementioning

confidence: 99%

See 1 more Smart Citation

Heat Shock Proteins hsp60 and hsp70: Their Roles in Folding, Assembly and Membrane Translocation of Proteins

Langer¹,

Neupert²

1991

Current Topics in Microbiology and Immunology

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“…Bochkareva et al (6) showed that GroEL interacts specifically with the immature forms of ,-lactamase and chloramphenicol acetyltransferase, befitting a chaperonin. The dissociation of this complex was again dependent on the presence of ATP.…”

mentioning

confidence: 99%

Regulation and sequence of the Synechococcus sp. strain PCC 7942 groESL operon, encoding a cyanobacterial chaperonin

1990

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The molecular chaperonins such as GroEL are now widely regarded as essential components for the stabilization of integral membrane or secretory proteins before membrane insertion or translocation, as well as for the assembly of macromolecular complexes such as ribulose bisphosphate carboxylase-oxygenase. The groESL operon of Synechococcus sp. strain PCC 7942 was cloned as two independent lacZ-groEL translational fusions by immunoscreening a lambda ZAP genomic expression library and then sequenced. The derived amino acid sequences of the GroES and GroEL proteins demonstrated very high levels of amino acid identity with cognate chaperonins from bacteria and chloroplasts. The bicistronic 2.4-kilobase transcript from this operon, barely detectable in RNA preparations from cells grown at 30 degrees C, accumulated approximately 120-fold in preparations from cells grown for 20 min at 45 degrees C. Under these conditions, GroEL protein accumulated to 10-fold-higher levels. Primer extension analysis was used to identify a cyanobacterial heat shock promoter located at -81 base pairs from the groES initiation codon. The transcriptional -10 and -35 sequences differ slightly from Escherichia coli consensus heat shock promoter sequences.

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“…In particular, one class of chaperones (typified by GroEL in prokaryotes) consist of multisubunit toroidal ring assemblies and are believed to function by providing a sequestered environment in which aberrant folding and aggregation are prevented; the correctly folded polypeptide is ultimately discharged in an Mg-ATP-dependent reaction. These toroidal structures are termed chaperonins (6,10,19,28,34,35,46). Actin and tubulin are the major soluble cytoplasmic proteins in eukaryotic cells and are the subunits from which actin filaments and microtubules are assembled.…”

mentioning

confidence: 99%

Facilitated folding of actins and tubulins occurs via a nucleotide-dependent interaction between cytoplasmic chaperonin and distinctive folding intermediates.

Melki¹,

Cowan²

1994

Mol. Cell. Biol.

107

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In the cytoplasm of eukaryotes, the folding of actins and tubulins is facilitated via interaction with a heteromeric toroidal complex (cytoplasmic chaperonin). The folding reaction consists of the formation of a binary complex between the unfolded target protein and the chaperonin, followed by the ultimate release of the native polypeptide in an ATP-dependent reaction. Here we show that the mitochondrial chaperonin (cpn6O) and the cytoplasmic chaperonin both recognize a range of target proteins with different relative affinities; however, the cytoplasmic chaperonin shows the highest affinity for intermediates derived from unfolded tubulins and actins. These high-affinity actin and tubulin folding intermediates are distinct from the "molten globule" intermediates formed by noncytoskeletal target proteins in that they form relatively slowly. We show that the interaction between cytoplasmic chaperonin and unfolded target proteins depends on the chaperonin being in its ADP-bound state and that the release of the target protein occurs after a transition of the chaperonin to the ATP-bound state. Our data suggest a model in which ATP hydrolysis acts as a switch between conformational forms of the cytoplasmic chaperonin that interact either strongly or weakly with unfolded substrates.The biological function of most, if not all, proteins depends critically upon their three-dimensional structure. Although the information contained in the linear sequence of amino acids is thought to be sufficient. to specify this structure (2, 24), the correct folding of many proteins is not a spontaneous process under physiological conditions; rather, there is a requirement for interaction with a class of proteins or protein complexes known as molecular chaperones (reviewed in references 14, 18, and 39). In particular, one class of chaperones (typified by GroEL in prokaryotes) consist of multisubunit toroidal ring assemblies and are believed to function by providing a sequestered environment in which aberrant folding and aggregation are prevented; the correctly folded polypeptide is ultimately discharged in an Mg-ATP-dependent reaction. These toroidal structures are termed chaperonins (6,10,19,28,34,35,46). Actin and tubulin are the major soluble cytoplasmic proteins in eukaryotic cells and are the subunits from which actin filaments and microtubules are assembled. The folding of actins, tubulins, and actin-and tubulin-related proteins is facilitated by a chaperonin (15-17, 31, 49) that differs from its prokaryotic and mitochondrial homologs in that it is heteromeric: the multisubunit toroidal structure is assembled from eight different (though related) polypeptides (15, 38), one of which is the t-complex polypeptide TCP-1 (27, 42). As is the case for other chaperonins, the cytoplasmic chaperonin forms a stable binary complex with unfolded target polypeptides in the absence of Mg-ATP, and the hydrolysis of Mg-ATP is absolutely required for the generation of folded proteins (15-17). However, an important difference exists between the mecha...

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Transient association of newly synthesized unfolded proteins with the heat-shock GroEL protein

Cited by 402 publications

References 23 publications

Heat Shock Proteins hsp60 and hsp70: Their Roles in Folding, Assembly and Membrane Translocation of Proteins

Heat Shock Proteins hsp60 and hsp70: Their Roles in Folding, Assembly and Membrane Translocation of Proteins

Regulation and sequence of the Synechococcus sp. strain PCC 7942 groESL operon, encoding a cyanobacterial chaperonin

Facilitated folding of actins and tubulins occurs via a nucleotide-dependent interaction between cytoplasmic chaperonin and distinctive folding intermediates.

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