The acidocalcisome Ca2+‐ATPase (TgA1) of Toxoplasma gondii is required for polyphosphate storage, intracellular calcium homeostasis and virulence

Luo, Shuhong; Ruiz, Félix A.; Moreno, Silvia N.J.

doi:10.1111/j.1365-2958.2004.04464.x

Cited by 74 publications

(68 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Primary antibodies used for these studies included polyclonal anti-FLAG (Sigma) at 1:1,000 and anti-acetyl H3 [K18] (Abcam) at 1:500. Microneme secretion assays were carried out as described previously (8,29). Antibody to MIC2 and MIC4 was kindly provided by David Sibley (Washington University, St. Louis, MO); antibody to MIC5 and MIC11 was kindly provided by Vern Carruthers (Johns Hopkins Malaria Research Institute, Baltimore, MD).…”

Section: Methodsmentioning

confidence: 99%

Pair of Unusual GCN5 Histone Acetyltransferases and ADA2 Homologues in the Protozoan ParasiteToxoplasma gondii

et al. 2006

View full text Add to dashboard Cite

GCN5 is a histone acetyltransferase (HAT) essential for development in mammals and critical to stress responses in yeast. The protozoan parasite Toxoplasma gondii is a serious opportunistic pathogen. The study of epigenetics and gene expression in this ancient eukaryote has pharmacological relevance and may facilitate the understanding of these processes in higher eukaryotes. Here we show that the disruption of T. gondii GCN5 yields viable parasites, which were subsequently employed in a proteomics study to identify gene products affected by its loss. Promoter analysis of these TgGCN5-dependent genes, which were mostly parasite specific, reveals a conserved T-rich element. The loss of TgGCN5 does not attenuate virulence in an in vivo mouse model. We also discovered that T. gondii is the only invertebrate reported to date possessing a second GCN5 (TgGCN5-B). TgGCN5-B harbors a strikingly divergent N-terminal domain required for nuclear localization. Despite high homology between the HAT domains, the two TgGCN5s exhibit differing substrate specificities. In contrast to TgGCN5-A, which exclusively targets lysine 18 of H3, TgGCN5-B acetylates multiple lysines in the H3 tail. We also identify two ADA2 homologues that interact differently with the TgGCN5s. TgGCN5-B has the potential to compensate for TgGCN5-A, which probably arose from a gene duplication unique to T. gondii. Our work reveals an unexpected complexity in the GCN5 machinery of this primitive eukaryote.

show abstract

Section: Methodsmentioning

confidence: 99%

Pair of Unusual GCN5 Histone Acetyltransferases and ADA2 Homologues in the Protozoan ParasiteToxoplasma gondii

et al. 2006

View full text Add to dashboard Cite

show abstract

“…There is also evidence for the presence of a Ca 2þ -ATPase in acidocalcisomes from several eukaryotic microbes, such as T. cruzi (Scott & Docampo 2000), T. brucei (Rodrigues et al 1999a;Luo et al 2004), Dictyostelium discoideum (Marchesini et al 2002) and T. gondii (TgA1; Luo et al 2001;Luo et al 2005). Na þ /H þ and Ca 2þ /H þ exchanger activities have been detected in acidocalcisomes of T. brucei procyclic forms (Vercesi & Docampo 1996;Vercesi et al 1997) and in L. donovani promastigotes (Vercesi et al 2000).…”

Section: Pumps Channels and Exchangers Of Acidocalcisomesmentioning

confidence: 99%

Evolution of acidocalcisomes and their role in polyphosphate storage and osmoregulation in eukaryotic microbes

Docampo

Ulrich

Moreno

2010

Phil. Trans. R. Soc. B

Self Cite

103

View full text Add to dashboard Cite

Acidocalcisomes are acidic electron-dense organelles, rich in polyphosphate (poly P) complexed with calcium and other cations. While its matrix contains enzymes related to poly P metabolism, the membrane of the acidocalcisomes has a number of pumps (Ca 2+ -ATPase, V-H + -ATPase, H + -PPase), exchangers (Na + /H + , Ca 2+ /H + ), and at least one channel (aquaporin). Acidocalcisomes are present in both prokaryotes and eukaryotes and are an important storage of cations and phosphorus. They also play an important role in osmoregulation and interact with the contractile vacuole complex in a number of eukaryotic microbes. Acidocalcisomes resemble lysosome-related organelles (LRO) from mammalian cells in many of their properties. They share similar morphological characteristics, acidic properties, phosphorus contents and a system for targeting of their membrane proteins through adaptor complex-3 (AP-3). Storage of phosphate and cations may represent the ancestral physiological function of acidocalcisomes, with cation and pH homeostasis and osmoregulatory functions derived following the divergence of prokaryotes and eukaryotes.

show abstract

“…4 A and B). DAPI staining was used to visualize Poly-P accumulation, which upon binding exhibits strong fluorescence emission at 530 nm (33,34). DAPI staining was greatly reduced in the tor3 − mutant, which again was reversed upon restoration of TOR3 (Fig.…”

Section: Infectivity Of L Major Tor3mentioning

confidence: 99%

Expansion of the target of rapamycin (TOR) kinase family and function in Leishmania shows that TOR3 is required for acidocalcisome biogenesis and animal infectivity

Silva

Beverley

2010

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Target of rapamycin (TOR) kinases are key regulators of cell growth, proliferation, and structure in eukaryotes, processes that are highly coordinated during the infectious cycle of eukaryotic pathogens. Database mining revealed three TOR kinases in the trypanosomatid parasite Leishmania major, as defined by homology to the phosphoinositide 3-kinase-related kinase (PIKK) family and a signature conserved FKBP12/rapamycin-binding domain. Consistent with the essential roles of TOR complexes in other organisms, we were unable to generate null TOR1 or TOR2 mutants in cultured L. major promastigotes. In contrast, tor3− null mutants were readily obtained; while exhibiting somewhat slower growth, tor3− maintained normal morphology, rapamycin sensitivity, and differentiation into the animal-infective metacyclic stage. Significantly, tor3− mutants were unable to survive or replicate in macrophages in vitro, or to induce pathology or establish infections in mice in vivo. The loss of virulence was associated with a defect in acidocalcisome formation, as this unique organelle was grossly altered in tor3-mutants and no longer accumulated polyphosphates. Correspondingly, tor3-mutants showed defects in osmoregulation and were sensitive to starvation for glucose but not amino acids, glucose being a limiting nutrient in the parasitophorous vacuole. Thus, in Leishmania, the TOR kinase family has expanded to encompass a unique role in AC function and biology, one that is essential for parasite survival in the mammalian infective stage. Given their important roles in cell survival and virulence, inhibition of TOR kinase function in trypanosomatids offers an attractive target for chemotherapy.chemotherapy | protozoan parasite | Trypanosomatidae | virulence | Kinetoplastida

show abstract

The acidocalcisome Ca²⁺‐ATPase (TgA1) of Toxoplasma gondii is required for polyphosphate storage, intracellular calcium homeostasis and virulence

Cited by 74 publications

References 32 publications

Pair of Unusual GCN5 Histone Acetyltransferases and ADA2 Homologues in the Protozoan ParasiteToxoplasma gondii

Pair of Unusual GCN5 Histone Acetyltransferases and ADA2 Homologues in the Protozoan ParasiteToxoplasma gondii

Evolution of acidocalcisomes and their role in polyphosphate storage and osmoregulation in eukaryotic microbes

Expansion of the target of rapamycin (TOR) kinase family and function in Leishmania shows that TOR3 is required for acidocalcisome biogenesis and animal infectivity

Contact Info

Product

Resources

About