The Hsp70/J-protein machinery of the African trypanosome, Trypanosoma brucei

Bentley, Stephen; Jamabo, Miebaka; Boshoff, Aileen

doi:10.1007/s12192-018-0950-x

Cited by 14 publications

(30 citation statements)

References 142 publications

(240 reference statements)

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“…Both proteins cooperate with the bacterial DnaK/DnaJ/GrpE (KJE) system, which is highly homologous to the mitochondrial Hsp70 system [51], and their chaperone-active reduced forms maintain client proteins in a refolding-competent conformation. An in silico survey of the Hsp70/J-protein machinery of African trypanosomes revealed 12 putative Hsp70 proteins and 67 putative J-proteins [64]. Many of these proteins were predicted or experimentally shown to be localized in the mitochondrion.…”

Section: Discussionmentioning

confidence: 99%

An essential thioredoxin-type protein of Trypanosoma brucei acts as redox-regulated mitochondrial chaperone

et al. 2019

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Most known thioredoxin-type proteins (Trx) participate in redox pathways, using two highly conserved cysteine residues to catalyze thiol-disulfide exchange reactions. Here we demonstrate that the so far unexplored Trx2 from African trypanosomes (Trypanosoma brucei) lacks protein disulfide reductase activity but functions as an effective temperature-activated and redox-regulated chaperone. Immunofluorescence microscopy and fractionated cell lysis revealed that Trx2 is located in the mitochondrion of the parasite. RNA-interference and gene knock-out approaches showed that depletion of Trx2 impairs growth of both mammalian bloodstream and insect stage procyclic parasites. Procyclic cells lacking Trx2 stop proliferation under standard culture conditions at 27°C and are unable to survive prolonged exposure to 37°C, indicating that Trx2 plays a vital role that becomes augmented under heat stress. Moreover, we found that Trx2 contributes to the in vivo infectivity of T. brucei. Remarkably, a Trx2 version, in which all five cysteines were replaced by serine residues, complements for the wildtype protein in conditional knock-out cells and confers parasite infectivity in the mouse model. Characterization of the recombinant protein revealed that Trx2 can coordinate an iron sulfur cluster and is highly sensitive towards spontaneous oxidation. Moreover, we discovered that both wildtype and mutant Trx2 protect other proteins against thermal aggregation and preserve their ability to refold upon return to non-stress conditions. Activation of the chaperone function of Trx2 appears to be triggered by temperature-mediated structural changes and inhibited by oxidative disulfide bond formation. Our studies indicate that Trx2 acts as a novel chaperone in the unique single mitochondrion of T. brucei and reveal a new perspective regarding the physiological function of thioredoxin-type proteins in trypanosomes.

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Section: Discussionmentioning

confidence: 99%

An essential thioredoxin-type protein of Trypanosoma brucei acts as redox-regulated mitochondrial chaperone

et al. 2019

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“…In Leishmania and Trypanosoma cruzi , heat shock proteins have been shown to play an essential role in stress-induced stage differentiation and are important for disease progression and transmission [4–5], making this protein family an attractive chemotherapeutic target. The completion of the Trypanosoma brucei ( T. brucei ) genome has expedited transcriptome and proteome analyses and revealed that the extracellular parasite has an expanded and diverse Hsp70 and J-protein complement, with the parasite possessing cytosolic Hsp70 members that display atypical Hsp70 features [6].…”

Section: Introductionmentioning

confidence: 99%

“…A recent in silico investigation revealed that the T. brucei genome was found to encode 12 members of the Hsp70 superfamily, with 8 members from the Hsp70/HSPA family and 4 Hsp110/HSPH family members [6]. The same study identified 67 putative J-proteins, with 5 type I J-proteins [6]. Phenotypic knockdown of T. brucei genes using RNAi, conducted by Alsford and colleagues [21], demonstrated that the Hsp70/J-protein machinery plays a prominent role in trypanosome biology, as the loss of certain members of these protein families impacted the survival and fitness of the parasite at various stages of its life cycle.…”

Section: Introductionmentioning

confidence: 99%

“…It has been proposed that TbHsp70 is cytosolic and a vital component of the heat shock response as it plays a key role by providing cytoprotection against cellular stress [6]. The Hsp70 orthologue in Leishmania chagasi was been linked to the parasite’s resistance to macrophage-induced oxidative stress [22], and has been shown in several Leishmania spp.…”

Section: Introductionmentioning

confidence: 99%

“…to be linked to parasite’s resistance to pentavalent antimonial treatment, as it induces Hsp70 expression which provides stress tolerance against the drug [23–24]. Based on phylogeny, TbHsp70.4 was found to form a distinct Hsp70/HSPA group unique to kinetoplastid parasites, with no obvious mammalian orthologues and a divergent C-terminal EEVD motif [6]. The Hsp70.4 orthologue in Leishmania major was shown to be cytoplasmic and constitutively expressed [25].…”

Section: Introductionmentioning

confidence: 99%

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Trypanosoma bruceiJ protein 2 functionally cooperates with the cytosolic Hsp70.4 and Hsp70 proteins

Bentley

Boshoff

2019

Preprint

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30The etiological agent of African trypanosomiasis, Trypanosoma brucei, has been identified to 31 possess an expanded and diverse group of heat shock proteins, that have been implicated in 32 cytoprotection, differentiation, and subsequently progression and transmission of the disease. 33 Heat shock protein 70 is a highly conserved and ubiquitous molecular chaperone that is 34 important in maintaining protein homeostasis in the cell. Its function is regulated by a wide 35 range of co-chaperones; and inhibition of these functions and interactions with co-chaperones 36 are emerging as potential therapeutic targets for numerous diseases. This study sought to 37 biochemically characterize the cytosolic Hsp70 and Hsp70.4 proteins and to investigate if they 38 form a functional partnership with the Type I J-protein, Tbj2. The cytosolic localisation of the 39 proteins was confirmed by accessing the TrypTag endogenous tagging microscopy database. 40Expression of TbHsp70 was shown to be heat inducible, whilst TbHsp70.4 was constitutively 41 expressed. The basal ATPase activities of TbHsp70.4 and TbHsp70 were stimulated by Tbj2. 42It was further determined that Tbj2 forms a functional partnership with TbHsp70 and 43 TbHsp70.4 as the J-protein was shown to stimulate the ability of both proteins to mediate the 44 refolding of chemically denatured β-galactosidase. This study provides further insight into this 45 important class of proteins which may contribute to the development of new therapeutic 46 strategies to combat African Trypanosomiasis. 47 48 49 50 51 52 53 54 3 55 Introduction 56 African trypanosomiasis, a neglected tropical disease, afflicts humans as well as domestic and 57 wild animals, and has a detrimental impact on socioeconomic development in sub-Saharan 58 Africa [1]. There is a need for the development of more effective and safer chemotherapies to 59 treat the disease, due to existing drug toxicity, growing parasite resistance and the lack of a 60 vaccine [2]. The Hsp70/J-protein chaperone machinery has been implicated to play an integral 61 role in the development, differentiation, and survival of protozoan parasites, as they transition 62 through the various stages of their life cycle [3]. In Leishmania and Trypanosoma cruzi, heat 63 shock proteins have been shown to play an essential role in stress-induced stage differentiation 64 and are important for disease progression and transmission [4-5], making this protein family 65 an attractive chemotherapeutic target. The completion of the Trypanosoma brucei (T. brucei) 66 genome has expedited transcriptome and proteome analyses and revealed that the extracellular 67 parasite has an expanded and diverse Hsp70 and J-protein complement, with the parasite 68 possessing cytosolic Hsp70 members that display atypical Hsp70 features [6]. 69 70 The Hsp70 protein family is ubiquitous and plays an integral role in protein quality control and 71 maintaining protein homeostasis under normal and stressful conditions [7-8]. Evolution has 72 given rise to multiple ...

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General Structural and Functional Features of Molecular Chaperones

Edkins

Boshoff

2021

Advances in Experimental Medicine and Biology

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The Hsp70/J-protein machinery of the African trypanosome, Trypanosoma brucei

Cited by 14 publications

References 142 publications

An essential thioredoxin-type protein of Trypanosoma brucei acts as redox-regulated mitochondrial chaperone

An essential thioredoxin-type protein of Trypanosoma brucei acts as redox-regulated mitochondrial chaperone

Trypanosoma bruceiJ protein 2 functionally cooperates with the cytosolic Hsp70.4 and Hsp70 proteins

General Structural and Functional Features of Molecular Chaperones

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