Biology subjects

Lauruol, F.

Publications and source records attributed to Lauruol, F..

3 recordsLinked to original sources

bioRxiv2026

Characterization of Sec14 domain-containing proteins in the malaria parasite Plasmodium falciparum.

Malaria, of which the most virulent form is caused by Plasmodium falciparum parasites, remains a major global health burden. The appearance of resistance to first line treatments artemisinin-based therapies, emphasizes the need to identify new parasite vulnerabilities to develop new therapeutics. Phosphoinositides are central regulators of membrane identity, vesicular trafficking, and signaling, and their synthesis depends on tightly controlled phosphatidylinositol transfer by Sec14-like phosphatidylinositol transfer proteins in many eukaryotes, yet their roles in P. falciparum remain poorly defined. Here, we analyzed six P. falciparum Sec14 domain-containing proteins: PfSec14-1 (PF3D7_0626400), PfSec14-2 (PF3D7_0629900), PfSec14-3 (PF3D7_0717100), PfSec14-4 (PF3D7_0920700), PfSec14-5 (PF3D7_1007200), and PfSec14-6 (PF3D7_1127600). Domain organization segregates these proteins into a BNIP-2 and Cdc42GAP homology (BCH) subfamily (PfSec14-3, PfSec14-5) and a canonical Sec14 subfamily (PfSec14-1, PfSec14-2, PfSec14-4, PfSec14-6). Yeast complementation assays showed that PfSec14-1, PfSec14-4, and PfSec14-6 partially rescue growth of a temperature-sensitive sec14 mutant, suggesting phosphatidylinositol and phosphatidylcholine transfer activity. Gene disruption revealed that PfSec14-1 is important for asexual blood-stage proliferation, whereas PfSec14-2 is dispensable under standard culture conditions. In contrast, mislocalization of PfSec14-1 and PfSec14-4 using a knock-sideways approach did not impair asexual growth. Subcellular localization indicates distinct distributions for PfSec14-1, PfSec14-2, and PfSec14-4. Together, these findings reveal functional and spatial diversification of Sec14-like phosphatidylinositol transfer proteins in P. falciparum.

microbiology↗

bioRxiv2024

Characterization of the Plasmodium falciparum homologue of Vps16, a member of the Vps-2 C tethering complex.

The organelles of the apical complex (rhoptries, micronemes and dense granules) are critical for erythrocyte invasion by the malaria parasite Plasmodium falciparum. Though they have essential roles in the parasite lifecycle, the mechanisms behind their biogenesis are still poorly defined. The Class C Vps proteins Vps11, 16, 18 and 33 constitute the core of the CORVET and HOPS complexes implicated in vesicle tethering and fusion in the eukaryotic endolysosomal system. Work in the model apicomplexan Toxoplasma gondii has revealed that TgVps11 is essential for the generation of the apical complex. P. falciparum possesses all the four subunits of the Vps-C complex but their function is currently unknown. We here present an initial characterization of the P. falciparum orthologue of Vps16, a member of the Vps-C complex. Our structural predictions suggest that the structure of PfVps16 is similar to its other eukaryotic counterparts and that the binding region responsible for its interaction with PfVps33 is conserved. We next show that PfVps16 is expressed throughout the asexual erythrocytic cycle and that it is potentially associated with the rhoptries in schizont stage parasites. Finally, we present our unsuccessful attempts at studying its function using knock sideways.

microbiology↗

bioRxiv2021

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 [A] 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 summaryTrypanosomes 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.

cell biology↗