The Peptidyl-prolyl Isomerase Domain of the CyP-40 Cyclophilin Homolog Cpr7 Is Not Required to Support Growth or Glucocorticoid Receptor Activity in Saccharomyces cerevisiae

Duina, Andrea A.; Marsh, James A.; Kurtz, Richard; Chang, Hui; Lindquist, Susan; Gaber, Richard F.

doi:10.1074/jbc.273.18.10819

Cited by 52 publications

(56 citation statements)

References 43 publications

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“…We established that sequences outside the PPIase domain are responsible for Cpr7 function. Cpr7-R64A, which alters a residue predicted to be required for catalytic activity (Duina et al 1998b), was able to support viability in cpr7hsc82hsp82 cells expressing hsp82D211-264 (not shown). The chimeric constructs as well as the isolated TPR domain (amino acids 193-393) that supported Cpr7 functions included the TPR domain as well as a linker region postulated to be important for chaperone activity (Mok et al 2006).…”

Section: Discussionmentioning

confidence: 99%

“…Cpr6 and Cpr7 contain two main domains: an amino-terminal PPIase domain and a carboxy-terminal TPR domain. The PPIase domain of Cpr7 is dispensable for growth (Duina et al 1998b). We made chimeras in which the PPIase domains were swapped, creating Cpr6 PPIase domain/Cpr7 TPR domain (6PPI/7TPR) and Cpr7 PPIase domain/Cpr6 TPR domain (7PPI/6TPR).…”

Section: Tpr Domain Of Cpr7 Specifies Its In Vivo Functionsmentioning

confidence: 99%

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Chaperoning the Chaperone: A Role for the Co-chaperone Cpr7 in Modulating Hsp90 Function in Saccharomyces cerevisiae

Zuehlke

Johnson

2012

Genetics

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Heat-shock protein 90 (Hsp90) of Saccharomyces cerevisiae is an abundant essential eukaryotic molecular chaperone involved in the activation and stabilization of client proteins, including several transcription factors and oncogenic kinases. Hsp90 undergoes a complex series of conformational changes and interacts with partner co-chaperones such as Sba1, Cpr6, Cpr7, and Cns1 as it binds and hydrolyzes ATP. In the absence of nucleotide, Hsp90 is dimerized only at the carboxy-terminus. In the presence of ATP, Hsp90 also dimerizes at the amino-terminus, creating a binding site for Sba1. Truncation of a charged linker region of yeast Hsp90 (Hsp82Dlinker) was known to disrupt the ability of Hsp82 to undergo amino-terminal dimerization and bind Sba1. We found that yeast expressing Hsp82Dlinker constructs exhibited a specific synthetic lethal phenotype in cells lacking CPR7. The isolated tetratricopeptide repeat domain of Cpr7 was both necessary and sufficient for growth in those strains. Cpr6 and Cpr7 stably bound the carboxyterminus of wild-type Hsp82 only in the presence of nonhydrolyzable ATP and formed an Hsp82-Cpr6-Cpr7 ternary complex. However, in cells expressing Hsp82Dlinker or lacking CPR7, Cpr6 was able to bind Hsp82 in the presence or absence of nucleotide. Overexpression of CNS1, but not of other co-chaperones, in cpr7 cells restored nucleotide-dependent Hsp82-Cpr6 interaction. Together, our results suggest that the in vivo functions of Cpr7 include modulating Hsp90 conformational changes, mediating proper signaling of the nucleotide-bound state to the carboxy-terminus of Hsp82, or regulating Hsp82-Cpr6 interaction.

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Section: Discussionmentioning

confidence: 99%

Section: Tpr Domain Of Cpr7 Specifies Its In Vivo Functionsmentioning

confidence: 99%

Chaperoning the Chaperone: A Role for the Co-chaperone Cpr7 in Modulating Hsp90 Function in Saccharomyces cerevisiae

Zuehlke

Johnson

2012

Genetics

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“…This results in an increasing amount of reactivatable intermediates of CS. In vivo the deletion of Cpr7 led to a decrease of steroid hormone receptor activation that could not be rescued by overexpression of Cpr6 (32,45). Additionally, it was shown that the PPIase domain of Cpr7 is dispensable for the activation of steroid hormone receptors (32).…”

Section: Catalytic Activity Of the Large Immunophilins In The Accelermentioning

confidence: 99%

“…Depletion of Cpr7 led to a growth defect that could not be rescued by the overexpression of Cpr6 (28,30). In vitro it was shown that Cpr6 is able to catalyze the isomerization of Xaa-Pro peptide bonds (29,31), whereas Cpr7 is assumed to be inactive (32). Here we analyzed and compared the function and stability of Cpr6 and Cpr7.…”

Section: Ppiasesmentioning

confidence: 99%

Cpr6 and Cpr7, Two Closely Related Hsp90-associated Immunophilins from Saccharomyces cerevisiae, Differ in Their Functional Properties

Mayr

Richter

Lilie

et al. 2000

Journal of Biological Chemistry

106

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Hsp90 is an abundant cytosolic molecular chaperone. It controls the folding of target proteins including steroid hormone receptors and kinases in complex with several partner proteins. Prominent members of this protein family are large peptidyl prolyl cis/trans isomerases (PPIases), which catalyze the cis/trans isomerization of prolyl peptide bonds in proteins and possess chaperone activity. In Saccharomyces cerevisiae, two closely related large Hsp90-associated PPIases, Cpr6 and Cpr7, exist. We show here that these homologous proteins bind with comparable affinity to Hsp90 but exhibit significant structural and functional differences. Cpr6 is more stable than Cpr7 against thermal denaturation and displays an up to 100-fold higher PPIase activity. In contrast, the chaperone activity of Cpr6 is much lower than that of Cpr7. Based on these results we suggest that the two immunophilins perform overlapping but not identical tasks in the Hsp90 chaperone cycle. PPIases1 are enzymes that are able to catalyze the cis-trans isomerization of Xaa-Pro peptide bonds in short synthetic peptides as well as in proteins (1). The isomerization of these bonds is a slow process (2) and often a rate-determining step in protein folding (3-6). PPIases have been found in all organisms and subcellular compartments studied so far (1,7,8). Until now three unrelated families of PPIases could be identified: parvulins, cyclophilins, and FKBPs (1,5,9). Because of their inhibition by the immunosuppressive drugs cyclosporin A (CsA) or FK506/rapamycin, the cyclophilins and FKBPs are also termed immunophilins (10 -13). Several large immunophilins with a molecular mass of about 40 -54 kDa are components of the Hsp90 chaperone complex. In higher eukaryotes, FKBP51, FKBP52, and Cyp40 act together with Hsp90; in yeast these are Cpr6 and Cpr7, two cyclophilins. The Hsp90 complex seems to regulate the conformation of its target proteins. These substrates include steroid hormone receptors. Here, the Hsp90 chaperone cycle is well established (reviewed in Refs. 14 -16).In the case of the progesterone receptor, the receptor is bound to Hsp70 in an early complex (15,17). Then an intermediate complex is formed in which Hsp90, Hsp70, Hip, Hop, and perhaps Hsp40 participate. The last step of this activation cycle is a complex, consisting of the progesterone receptor, Hsp90, p23, and one of the large immunophilins. The specific function of the immunophilins in the chaperone cycle is far from clear. However, it is well established that progesterone receptor has to be bound in this complex to allow binding of the hormone, dimerization, and subsequently, interaction with DNA. In the absence of hormone, the receptor is released from the complex, and the cycle starts again. The large immunophilins interact with Hsp90 via tetratricopeptide repeats (18 -21). The partner site for the tetratricopeptide-repeat motifs is located in a 12-kDa carboxyl-terminal domain of Hsp90 (22, 23). The tetratricopeptide-repeat proteins compete with each other for this binding site (18,1...

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“…A large body of evidence suggests that the PPIase activity of immunophilins is responsible for various functions (16,46,47). However, the controversy regarding the chaperone function of small immunophilins has yet to be fully settled (18,20,48).…”

Section: And References Therein)mentioning

confidence: 99%

A Single-domain Cyclophilin from Leishmania donovaniReactivates Soluble Aggregates of Adenosine Kinase by Isomerase-independent Chaperone Function

Chakraborty¹,

Das²,

Datta³

et al. 2002

Journal of Biological Chemistry

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Disaggregation and reactivation of aggregated proteins by chaperones is well established. However, little is known regarding such kind of function of single-domain small cyclophilins (CyPs). Here we demonstrate that, with increasing concentrations, fully active adenosine kinase (AdK) of Leishmania donovani tends to form soluble aggregates, resulting in inactivation. Using this inactive enzyme as the substrate, it is shown that a CyP from L. donovani (LdCyP) alone can cause complete disaggregation, leading to reactivation of the enzyme. The reactivating ability of LdCyP remains unaffected even in the presence of cyclosporin A and macromolecular crowding agents. The reactivation occurs noncatalytically and is reversible. A truncated LdCyP, devoid of 88 amino acids from the N terminus, is found to be required in near stoichiometric proportion to reactivate AdK, suggesting essentiality of the C-terminal region. Gel filtration and light-scattering experiments together with protein cross-linking studies revealed that both full-length LdCyP and the truncated form directly interact with AdK and convert oligomeric forms of the enzyme to monomeric state. Homology modeling studies suggest that the exposed hydrophobic residues of LdCyP, by interacting with solvent-accessible hydrophobic surface of AdK, pull apart its aggregated inactive oligomers to functional monomers. Clearly, the results are consistent with the interpretation that the higher efficiency of the truncated LdCyP is most likely due to increased exposure of the hydrophobic residues on its surface. These observations, besides establishing L. donovani AdK as one of the model enzymes to study aggregation-disaggregation of proteins, raise the possibility that single-domain small CyPs, under physiological conditions, may regulate the activity of aggregation-prone proteins by ensuring their disaggregation.

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The Peptidyl-prolyl Isomerase Domain of the CyP-40 Cyclophilin Homolog Cpr7 Is Not Required to Support Growth or Glucocorticoid Receptor Activity in Saccharomyces cerevisiae

Cited by 52 publications

References 43 publications

Chaperoning the Chaperone: A Role for the Co-chaperone Cpr7 in Modulating Hsp90 Function in Saccharomyces cerevisiae

Chaperoning the Chaperone: A Role for the Co-chaperone Cpr7 in Modulating Hsp90 Function in Saccharomyces cerevisiae

Cpr6 and Cpr7, Two Closely Related Hsp90-associated Immunophilins from Saccharomyces cerevisiae, Differ in Their Functional Properties

A Single-domain Cyclophilin from Leishmania donovaniReactivates Soluble Aggregates of Adenosine Kinase by Isomerase-independent Chaperone Function

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