Reminder: Today, @ParaFrap Webinar at 3pm : Karine FRENAL - “Insights into the molecular organization and functions of the basal pole of #Toxoplasma gondii​“ - #MFP_lab Bordeaux @univbordeaux @CNRSAquitaine

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🚨 Next @ParaFrap Webinar: Karine FRENAL - “Insights into the molecular organization and functions of the basal pole of Toxoplasma gondii​“ - #MFP_lab Bordeaux @univbordeaux @CNRSAquitaine

🗓️ Thursday, June 15, 3pm CEST

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bit.ly/ParaFrapWeb

💼Job offer: External Recruitment Competition - Assistant Engineer in biology

🔬Team @ProParaCyto (M. Bonhivers & D. Robinson), #MFP_Lab @univbordeaux

👩‍🔬Study of the cytoskeleton in T. brucei and T. gondii parasites (molecular and cell biology, imaging

labex-parafrap.fr/en/job-offers/…

"Metabolic contest", une nouvelle façon de contrôler l’utilisation des sources de carbone | CNRS Biologie Dans cet article publié dans la revue PLoS Biology, les scientifiques décrivent un nouveau mécanisme moléculaire perm

Metabolic contest, a new way to control the utilization of carbon sources. Check out this study published in @PLOSBiology, involving scientists from @ParaFrap @CNRS @CNRSAquitaine @univbordeaux @INSB_CNRS
@BringaudF. #MFP_Lab #metabolism #parasite #science

insb.cnrs.fr/fr/cnrsinfo/me…

The Trypanosome UDP-Glucose Pyrophosphorylase Is Imported by Piggybacking into Glycosomes, Where Unconventional Sugar Nucleotide Synthesis Takes Place | mBio Unusual compartmentalization of metabolic pathways within organelles is one of the most enigmatic features of trypanosomatids. These unicellular eukaryotes are the only organisms that sequestered glycolysis inside peroxisomes (glycosomes), although the ...

Check out the latest study of our former @ParaFrap PhD stud @OVillafraz: The Trypanosome UDP-Glucose Pyrophosphorylase Is Imported by Piggybacking into Glycosomes, Where Unconventional Sugar Nucleotide Synthesis Takes Place @mbiojournal @BringaudF #MFP_lab

journals.asm.org/doi/10.1128/mB…

New review on diagnosis of animal african trypanosomiases, by Magamba Tounkara @MagTOUNK, ParaFrap PhD student supervised by L. Rivière in @BringaudF team #MFP_Lab, in the bulletin of Association des Anciens Élèves de l'Institut Pasteur. Check it out

aaeip.fr/bulletin/Somma…

What a #parasite! Read the latest article of @BringaudF's team on the selective advantage of gene rearrangement in the FRD locus in #Trypanosoma brucei, published in @jbiolchem. #MFP_lab

sciencedirect.com/science/articl…

The trypanosome UDP-glucose pyrophosphorylase is imported by piggybacking into glycosomes where unconventional sugar nucleotide synthesis takes place Glycosomes are peroxisome-related organelles of trypanosomatid parasites containing metabolic pathways usually present in the cytosol of other eukaryotes, such as glycolysis and biosynthesis of sugar nucleotides. UDP-glucose pyrophosphorylase (UGP), the enzyme responsible for the synthesis of the sugar nucleotide UDP-glucose, is localised in the cytosol and glycosomes of the bloodstream and procyclic trypanosomes, despite the absence of any known peroxisomal targeting signal (PTS1 and PTS2). The questions we addressed here are ( i ) is the unusual glycosomal biosynthetic pathway of sugar nucleotide functional and ( ii ) how the PTS-free UGP is imported into glycosomes? We showed that UGP is imported into glycosomes by piggybacking on the glycosomal PTS1-containing phosphoenolpyruvate carboxykinase (PEPCK) and identified the domains involved in the UGP/PEPCK interaction. Proximity ligation assays revealed that this interaction occurs in 3-10% of glycosomes, suggesting that these correspond to organelles competent for protein import. We also showed that UGP is essential for growth of trypanosomes and that both the glycosomal and cytosolic metabolic pathways involving UGP are functional, since the lethality of the knock-down UGP mutant cell line ( RNAi UGP) was rescued by expressing a recoded UGP in the organelle ( RNAi UGP/ EXP rUGP-GPDH). Our conclusion was supported by targeted metabolomic analyses (IC-HRMS) showing that UDP-glucose is no longer detectable in the RNAi UGP mutant, while it is still produced in cells expressing UGP exclusively in the cytosol (PEPCK null mutant) or glycosomes ( RNAi UGP/ EXP rUGP-GPDH). Trypanosomatids are the only known organisms to have selected functional peroxisomal (glycosomal) sugar nucleotide biosynthetic pathways in addition to the canonical cytosolic ones. Importance Unusual compartmentalization of metabolic pathways within organelles is one of the most enigmatic features of trypanosomatids. These unicellular eukaryotes are the only organisms that sequestered glycolysis inside peroxisomes (glycosomes), although the selective advantage of this compartmentalization is still not clear. Trypanosomatids are also unique for the glycosomal localisation of enzymes of the sugar nucleotide biosynthetic pathways, which are also present in the cytosol. Here we showed that the cytosolic and glycosomal pathways are functional. Like in all other eukaryotes, the cytosolic pathways feed glycosylation reactions, however the role of the duplicated glycosomal pathways is currently unknown. We also showed that one of these enzymes (UGP) is imported into glycosomes by piggybacking on another glycosomal enzyme (PEPCK), which are not functionally related. The UGP/PEPCK association is unique since all piggybacking examples reported to date involve functionally related interacting partners, which broadens the possible combinations of carrier-cargo proteins being imported as hetero-oligomers.

BreakingNews: cytosolic & glycosomal sugar nucleotide synthesis are functional in #trypanosomes + piggyback of 2 functionally unrelated proteins. Curious? Read the preprint by @OVillafraz &al. @BringaudF @Eri_pinedar #MFP_lab @ApicoLipid @biorxivpreprint

doi.org/10.1101/2021.0…

Structural and functional studies of the first tripartite protein complex at the Trypanosoma brucei flagellar pocket collar The flagellar pocket (FP) is the only endo- and exocytic organelle in most trypanosomes and, as such, is essential throughout the life cycle of the parasite. The neck of the FP is maintained enclosed around the flagellum via the flagellar pocket collar (FPC). The FPC is a macromolecular cytoskeletal structure and is essential for the formation of the FP and cytokinesis. FPC biogenesis and structure are poorly understood, mainly due to the lack of information on FPC composition. To date, only two FPC proteins, BILBO1 and FPC4, have been characterized. BILBO1 forms a molecular skeleton upon which other FPC proteins can, theoretically, dock onto. We previously identified FPC4 as the first BILBO1 interacting partner and demonstrated that its C-terminal domain interacts with the BILBO1 N-terminal domain (NTD). Here, we report the characterization of a new FPC component and BILBO1 partner protein, BILBO2 (Tb927.6.3240) by yeast two-hybrid screen, bioinformatics, functional and structural studies. We show that BILBO2 colocalizes with BILBO1 and can modulate the shape of the BILBO1 filament by interacting with the BILBO1 EF-hand domains. Further, we demonstrate that BILBO1 and BILBO2 share a homologous NTD domain and that both domains interact with FPC4. We have determined a 1.9 Å resolution crystal structure of the BILBO2 NTD in complex with the FPC4 BILBO1-binding domain. Together with mutational analyses, our studies reveal key residues for the function of the BILBO2 NTD and its interaction with FPC4 and evidenced a tripartite interaction between BILBO1, BILBO2, and FPC4. Our work sheds light on the first atomic structure of an FPC protein complex and represents a significant step in deciphering the FPC function in Trypanosoma brucei and other pathogenic kinetoplastids. Author summary Trypanosomes belong to a group of zoonotic, protist, parasites that are found in Africa, Asia, South America, and Europe and are responsible for severe human and animal diseases. They all have a common structure called the flagellar pocket (FP). In most trypanosomes, all macromolecular exchanges between the trypanosome and the environment occur via the FP. The FP is thus essential for cell viability and evading the host immune response. We have been studying the flagellar pocket collar (FPC), an enigmatic macromolecular structure at the neck of the FP, and demonstrated its essentiality for the biogenesis of the FP. We demonstrated that BILBO1 is an essential protein of the FPC that interacts with other proteins including a microtubule-binding protein FPC4. Here we identify another bona fide FPC protein, BILBO2, so named because of close similarity with BILBO1 in protein organization and functional domains. We demonstrate that BILBO1 and BILBO2 share a common N-terminal domain involved in the interaction with FPC4, and illustrate a tripartite interaction between BILBO1, BILBO2, and FPC4. Our study also provides the first atomic view of two FPC components. These data represent an additional step in deciphering the FPC structure and function in T. brucei .

The new story of the D. Robinson @LocutustheBorg team is out. They characterised a new protein of the flagellar pocket of #Trypanosoma brucei. This work is part of Charlotte Isch's thesis, @ParaFrap alumni, supervised by @BonhiversMel #MFP_lab #parasite

biorxiv.org/content/10.110…