Polyphosphate and acidocalcisomes

Lander, Noelia; Cordeiro, Ciro D.; Huang, Guozhong; Docampo, Roberto

doi:10.1042/bst20150193

Cited by 71 publications

(56 citation statements)

References 62 publications

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“…C). Acidocalcisomes are the main cellular storage compartment for polyphosphate in trypanosomes (Lander et al ., ). However, examination of the cells by super‐resolution microscopy with antibodies against the vacuolar proton pyrophosphatase (TbVP1) showed no apparent difference in labeling or distribution of acidocalcisomes between control and TbIPMK mutant cells (Supporting Information Fig.…”

Section: Resultsmentioning

confidence: 97%

“…Yeast lacking Arg82p have no observable inorganic polyphosphate accumulation (Lonetti et al ., ). As polyphosphate has important roles in trypanosomes, including growth, response to osmotic stress, and maintenance of persistent infections (Lander et al ., ), we investigated whether deletion of soluble inositol polyphosphates affected the levels of polyphosphate in T . brucei .…”

Section: Resultsmentioning

confidence: 99%

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The inositol pyrophosphate synthesis pathway in Trypanosoma brucei is linked to polyphosphate synthesis in acidocalcisomes

Cordeiro

Saiardi

Docampo

2017

Molecular Microbiology

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Summary Inositol pyrophosphates are novel signaling molecules possessing high-energy pyrophosphate bonds and involved in a number of biological functions. Here, we report the correct identification and characterization of the kinases involved in the inositol pyrophosphate biosynthetic pathway in Trypanosoma brucei: inositol polyphosphate multikinase (TbIPMK), inositol pentakisphosphate 2-kinase (TbIP5K) and inositol hexakisphosphate kinase (TbIP6K). TbIP5K and TbIP6K were not identifiable by sequence alone and their activities were validated by enzymatic assays with the recombinant proteins or by their complementation of yeast mutants. We also analyzed T. brucei extracts for the presence of inositol phosphates using polyacrylamide gel electrophoresis and high performance liquid chromatography. Interestingly, we could detect inositol phosphate (IP), inositol 4,5-bisphosphate (IP2), inositol 1,4,5-trisphosphate (IP3) and inositol hexakisphosphate (IP6) in T. brucei different stages. Bloodstream forms unable to produce inositol pyrophosphates, due to downregulation of TbIPMK expression by conditional knockout, have reduced levels of polyphosphate and altered acidocalcisomes. Our study links the inositol pyrophosphate pathway to the synthesis of polyphosphate in acidocalcisomes, and may lead to better understanding of these organisms and provide new targets for drug discovery.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

The inositol pyrophosphate synthesis pathway in Trypanosoma brucei is linked to polyphosphate synthesis in acidocalcisomes

Cordeiro

Saiardi

Docampo

2017

Molecular Microbiology

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“…Acidocalcisomes, in fact, work as an acidic storage for divalent (Ca 2+ ) and heavy metal (Zn 2+ and Fe 2+ ) cations, due to their high polyphosphate content. 46 In view of this result, the role of acidocalcisomes as a feasible target of 15a was further investigated, by using acridine orange (AO) dye as an acidocalcisome pH indicator. 47 Not unexpectedly, the intraorganellar acidic pH was quenched by 15a, These studies notwithstanding, additional targets for styrylquinolines cannot be ruled out, as frequently found for other antileishmanial drugs, such as miltefosine 49,50 or paromomycin.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Structure-activity relationships and mechanistic studies of novel mitochondria-targeted, leishmanicidal derivatives of the 4-aminostyrylquinoline scaffold

Staderini

Piquero

Abengózar

et al. 2019

European Journal of Medicinal Chemistry

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“…In bacteria, polyPs can form granules in the nucleoid region, regulate the cell cycle (3), form cation-selective membrane channels (4), control cell motility (5), mediate cellular stress responses, for instance by preventing protein aggregation (6). In eukaryotes, polyPs have thus far been found in vacuoles or specialized acidocalcisomes (7) and form an important store for P i (8)(9)(10)(11) and divalent metal ions (12,13). At the physiological level, polyPs are involved in cell cycle control (14), in cell death responses (15), coagulation (16), skeletal mineralization (17) and in the posttranslational modification of proteins (18).…”

Section: Introductionmentioning

confidence: 99%

Molecular characterization of CHAD domains as inorganic polyphosphate binding modules

Lorenzo‐Orts

Hohmann

Zhu

et al. 2019

Preprint

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Inorganic polyphosphates (polyPs) are long polymers of orthophosphate units (P i ), linked by energyrich phosphoanhydride bonds. Conserved histidine α-helical (CHAD) domains of unknown biochemical function are often located at the C-terminus of polyP-metabolizing triphosphate tunnel metalloenzymes (TTMs), or can be found as stand-alone proteins in bacterial operons harboring polyP kinases or phosphatases. Here we report that bacterial, archaeal and eukaryotic CHAD domains are specific polyP binding modules. Crystal structures reveal that CHAD domains are formed by two fourhelix bundles, giving rise to a central cavity surrounded by two conserved basic surface patches.Different CHAD domains bind polyPs with dissociation constants ranging from the nano-to midmicromolar range, but not DNA or other P i -containing ligands. A 2.1 Å CHAD -polyP complex structure reveals the phosphate polymer binding across a central pore and along the two basic patches.Mutational analysis of CHAD -polyP interface residues validates the complex structure and reveals that CHAD domains evolved to bind long-chain polyPs. The presence of a CHAD domain in the polyPase ygiF enhances its enzymatic activity. In plants, CHAD domains bind polyP in vivo and localize to the nucleus and nucleolus, suggesting that plants harbor polyP stores in these compartments.We propose that CHAD domains may be used to engineer the properties of polyP-metabolizing enzymes and to specifically localize polyP stores in eukaryotic cells and tissues. (221 words)Significance A domain of unknown function termed CHAD, present in all kingdoms of life, is characterized as a specific inorganic polyphosphate binding domain. The small size of the domain and its high specificity for inorganic polyphosphates suggest that it could be used as a tool to locate inorganic polyphosphate stores in pro-and eukaryotic cells and tissues. operons expressing polyP metabolic enzymes (39). Recently, it was found that CHAD domaincontaining proteins specifically localize to polyP granules in the bacterium Ralstonia eutropha (40). In this study, we combine structural biology and quantitative biochemistry to define CHAD domains as polyP binding modules. ResultsWe located CHAD domains in the different kingdoms of life. According to Interpro (https://www.ebi.ac.uk/interpro), ~ 99 % of the annotated CHAD proteins correspond to bacteria, while only ~ 1 % (129 proteins) and 0.1 % (10 proteins) belong to archaea and eukaryota, respectively (Fig. 1A). We selected CHAD domain-containing proteins belonging to the three kingdoms of life: archaea (Sulfolobus solfataricus; termed SsCHAD hereafter), bacteria (Chlorobium tepidum; CtCHAD) and eukaryota (Ricinus communis or castor bean; RcCHAD) ( Fig 1A) (SI Appendix Fig. S1). Several of these CHAD proteins form part of gene clusters encoding polyP metabolizing enzymes, with the exception of RcCHAD (Fig. 1B).To confirm if indeed RcCHAD is expressed in Ricinus, we performed RT-PCR experiments using Ricinus cDNA prepared from leave extracts. We detected a transcri...

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Polyphosphate and acidocalcisomes

Cited by 71 publications

References 62 publications

The inositol pyrophosphate synthesis pathway in Trypanosoma brucei is linked to polyphosphate synthesis in acidocalcisomes

The inositol pyrophosphate synthesis pathway in Trypanosoma brucei is linked to polyphosphate synthesis in acidocalcisomes

Structure-activity relationships and mechanistic studies of novel mitochondria-targeted, leishmanicidal derivatives of the 4-aminostyrylquinoline scaffold

Molecular characterization of CHAD domains as inorganic polyphosphate binding modules

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