Golgi biogenesis in Toxoplasma gondii

Pelletier, Laurence; Stern, Charlene A.; Pypaert, Marc; Sheff, David; Ngô, Huân M.; Roper, Nitin; He, Cynthia Y.; Hu, Ke; Toomre, Derek; Coppens, Isabelle; Roos, David S.; Joiner, Keith A.; Warren, Graham

doi:10.1038/nature00946

Cited by 186 publications

(186 citation statements)

References 28 publications

Supporting

Mentioning

171

Contrasting

Order By: Relevance

“…Since N-and C-terminal tagging of TgROM1 resulted in the same localisation, the other ROMs were tagged only with an N-terminal myc-epitope. mycTgROM2 showed a focused staining at the apical side of the nucleus, typical of Golgi staining in T. gondii (Pelletier et al, 2002). Double immunofluoresce analysis with the Golgi marker GRASP-YFP (Pelletier et al, 2002), suggests that TgROM2 accumulates in a distinct region of the Golgi stack from GRASP-YFP, likely to correspond to the trans-Golgi network (TGN) (Fig.…”

Section: Subcellular Distribution Of the T Gondii Rom Proteasesmentioning

confidence: 87%

Apicomplexan rhomboids have a potential role in microneme protein cleavage during host cell invasion

Dowse

Pascall

Brown

et al. 2005

International Journal for Parasitology

112

129

View full text Add to dashboard Cite

Apicomplexan parasites secrete transmembrane (TM) adhesive proteins as part of the process leading to host cell attachment and invasion. These microneme proteins are cleaved in their TM domains by an unidentified protease termed microneme protein protease 1 (MPP1). The cleavage site sequence (IAYGG), mapped in the Toxoplasma gondii microneme proteins TgMIC2 and TgMIC6, is conserved in microneme proteins of other apicomplexans including Plasmodium species. We report here the characterisation of novel T. gondii proteins belonging to the rhomboid family of intramembrane-cleaving serine proteases. T. gondii possesses six genes encoding rhomboid-like proteins. Four are localised along the secretory pathway and therefore constitute possible candidates for MPP1 activity. Toxoplasma rhomboids TgROM1, TgROM2 and TgROM5 cleave the TM domain of Drosophila Spitz, an established substrate for rhomboids from several species, demonstrating that they are active proteases. In addition, TgROM2 cleaves chimeric proteins that contain the TM domains of TgMIC2 and TgMIC12. q

show abstract

Section: Subcellular Distribution Of the T Gondii Rom Proteasesmentioning

confidence: 87%

Apicomplexan rhomboids have a potential role in microneme protein cleavage during host cell invasion

Dowse

Pascall

Brown

et al. 2005

International Journal for Parasitology

112

129

View full text Add to dashboard Cite

show abstract

“…Given that TgASP1 was previously shown to reside in a novel compartment of the secretory system that potentially serves a link between the Golgi and the IMC (Shea et al, 2007), we investigated the localization of the cis-Golgi marker, GRASP by pYFP-GRASP transient transfection (Pelletier et al, 2002). No alteration of GRASP localization was observed (Fig.…”

Section: Tgasp1 Is Dispensable For T Gondii Growth In Vitro and In Vivomentioning

confidence: 99%

“…Transient tranfections were done with pPhil1-YFP (Gilk et al, 2006), pDLC-EGFP , pMORN-EGFP (Gubbels et al, 2006), and pGRASP-YFP (Pelletier et al, 2002) in RH and Tgasp1-strains. Co-localizations were done using anti-TgGAP45 antibodies as described previously with goat-anti-rabbit IgG conjugated Alexa-Fluor-594 as secondary antibodies.…”

Section: Immunofluorescence Assay (Ifa) and Confocal Microscopymentioning

confidence: 99%

Toxoplasma gondii aspartic protease 1 is not essential in tachyzoites

Polonais

Shea²,

Soldati‐Favre

2011

Experimental Parasitology

View full text Add to dashboard Cite

a b s t r a c tAspartic proteases are important virulence factors for pathogens and are recognized as attractive drug targets. Seven aspartic proteases (ASPs) have been identified in Toxoplasma gondii genome. Bioinformatics and phylogenetic analyses regroup them into five monophyletic groups. Among them, TgASP1, a coccidian specific aspartic protease related to the food vacuole plasmepsins, is associated with the secretory pathway in non-dividing cells and relocalizes in close proximity to the nascent inner membrane complex (IMC) of daughter cells during replication. Despite a potential role for TgASP1 in IMC formation, the generation of a conventional knockout of the TgASP1 gene revealed that this protease is not required for T. gondii tachyzoite survival or for proper IMC biogenesis.

show abstract

“…If the Golgi apparatus is responsible for its biogenesis, then it can be viewed as an autonomous organelle (Pelletier et al, 2002). If, on the other hand, it depends on the endoplasmic reticulum, then it can be viewed as a dependent organelle, which exists only as a consequence of ER functioning (Zaal et al, 1999;Bevis et al, 2002;Munro, 2002).…”

Section: Introductionmentioning

confidence: 99%

Rapid, Endoplasmic Reticulum-independent Diffusion of the Mitotic Golgi Haze

Axelsson

Warren

2004

MBoC

Self Cite

View full text Add to dashboard Cite

Early in mitosis, the mammalian Golgi apparatus disassembles, and fluorescence microscopy reveals Golgi clusters and an extensive, nonresolvable haze that either represents scattered vesicles or a merged endoplasmic reticulum (ER)-Golgi compartment. To help decide between these alternatives, we have carried out a combined microscopic and pharmacological analysis, by using a BS-C-1 cell line stably coexpressing ER and Golgi markers. Video fluorescence microscopy showed that these two organelles were morphologically distinguishable at all stages of mitosis, and photobleaching experiments showed that diffusion of the Golgi marker was unaffected by the presence of the ER. Fragmentation of the ER by using filipin III completely blocked diffusion of the ER marker but had no effect on the Golgi marker, unless it was first relocated to the ER by using brefeldin A. The Golgi haze was also studied using BODIPY ceramide. Its diffusion was slower in mitotic Golgi than in mitotic ER, but similar to that of a Golgi enzyme marker in the mitotic Golgi haze or in Golgi vesicles generated by ilimaquinone. Together, these results support the idea that the Golgi and the ER remain separate during mitosis and strongly suggest that Golgi markers move by vesicle diffusion, as opposed to lateral diffusion in continuous membranes. INTRODUCTIONThe status of the Golgi apparatus as an organelle has been the subject of a long-running debate that focused initially on the route taken by transiting cargo (cisternal maturation or vesicle-mediated transport; Glick and Malhotra, 1998;Pelham and Rothman, 2000) and, more recently, on the mechanisms of duplication and partitioning that underlie its biogenesis (Marsh and Howell, 2002;Munro, 2002). If the Golgi apparatus is responsible for its biogenesis, then it can be viewed as an autonomous organelle (Pelletier et al., 2002). If, on the other hand, it depends on the endoplasmic reticulum, then it can be viewed as a dependent organelle, which exists only as a consequence of ER functioning (Zaal et al., 1999;Bevis et al., 2002;Munro, 2002).Golgi partitioning during mitosis in animal cells has been particularly controversial, with models ranging from partitioning by Golgi elements themselves (Lucocq et al., 1989;Misteli and Warren, 1995;Jesch and Linstedt, 1998;Shima et al., 1998;Jesch et al., 2001;Jokitalo et al., 2001) to the partial or even complete merger of the Golgi with the ER, which then mediates the partitioning process (Thyberg and Moskalewski, 1992;Zaal et al., 1999;Kano et al., 2000;Terasaki, 2000). Although most biochemical experiments have yielded consistent results, suggesting a separation of the ER and Golgi during mitosis (Jesch and Linstedt, 1998;Farmaki et al., 1999;Jesch et al., 2001), microscopic experiments have often yielded contradictory results (Thyberg and Moskalewski, 1992;Shima et al., 1998;Zaal et al., 1999;Jokitalo et al., 2001).A particular issue has been the Golgi haze observed by fluorescence microscopy of mitotic cells. Breakdown and fragmentation of the Golgi ribbon a...

show abstract

Golgi biogenesis in Toxoplasma gondii

Cited by 186 publications

References 28 publications

Apicomplexan rhomboids have a potential role in microneme protein cleavage during host cell invasion

Apicomplexan rhomboids have a potential role in microneme protein cleavage during host cell invasion

Toxoplasma gondii aspartic protease 1 is not essential in tachyzoites

Rapid, Endoplasmic Reticulum-independent Diffusion of the Mitotic Golgi Haze

Contact Info

Product

Resources

About