Biology subjects

Avalos-Padilla, Y.

Publications and source records attributed to Avalos-Padilla, Y..

4 recordsLinked to original sources

bioRxiv2025

Liquid-liquid phase separation (LLPS) as a sensing and adaptation mechanism: An evidence-based hypothesis on AP2 transcription factors in the malaria parasite

BackgroundProtein liquid-liquid phase separation (LLPS) can be driven by prion-like domains (PrLDs) inside intrinsically disordered regions (IDRs). The causing agent of the deadliest form of human malaria, Plasmodium falciparum, has abundant prion-like proteins whose aggregation is presumed to have a functional role. Multiple members of the largest family of transcription factors in P. falciparum, AP2 (PfAP2), responsible for adapting the parasite gene response in different scenarios, were found in aggregation-prone protein screenings. ResultsWe show that the PfAP2s members carry the physicochemical determinants to perform LLPS forming biomolecular condensates in vivo. The long IDRs of PfAP2s could sense changes in the cellular microenvironment, and their PrLDs could drive conformational rearrangements. PfAP2s do not function as centralizing hubs for protein-protein interaction networks, but display significant preferred interactions among themselves, establishing a large, connected subnetwork. Predictions suggest that all PfAP2s have regions to localize into LLPS-condensates, while larger PfAP2s could initiate condensation. We show that four PfAP2 members co-localize in live P. falciparum, bearing the potential to be engaged in LLPS-condensates. ConclusionWe present bioinformatics analyses and experimental data obtained in live parasites suggesting that PfAP2s are able to direct LLPS in P. falciparum. We propose a model in which sensing by the parasite of cellular stresses like host transfer, temperature changes and energy depletion, and the corresponding gene responses are driven by LLPS where the PfAP2 family plays a fundamental role. Finally, we postulate targeting PfAP2 as a new therapeutic antimalarial strategy to curb the emergence of drug-resistant parasites.

bioinformatics↗

bioRxiv2024

Hexosamine Biosynthesis Disruption Impairs GPI Production and Arrests Plasmodium falciparum Growth at Schizont Stages

UDP-N-acetylglucosamine (UDP-GlcNAc) is a crucial sugar nucleotide for glycan synthesis in eukaryotes. In the malaria parasite Plasmodium falciparum, UDP-GlcNAc is synthesized via the hexosamine biosynthetic pathway (HBP) and is essential for glycosylphosphatidylinositol (GPI) anchor production, the most prominent form of protein glycosylation in the parasite. In this study, we explore a conditional knockout of glucosamine-6-phosphate N-acetyltransferase (PfGNA1), a key HBP enzyme. PfGNA1 depletion led to significant disruptions in HBP metabolites, impairing GPI biosynthesis and causing mislocalization of the merozoite surface protein 1 (MSP1), the most abundant GPI-anchored protein in the parasite. Furthermore, parasites were arrested at the schizont stage, exhibiting severe segmentation defects and an incomplete rupture of the parasitophorous vacuole membrane (PVM), preventing egress from host red blood cells. Our findings demonstrate the critical role of HBP and GPI biosynthesis in P. falciparum asexual blood stage development and underscore the potential of targeting these pathways as a therapeutic strategy against malaria. Author SummaryMalaria remains a major cause of illness and death, particularly in sub-Saharan Africa, with increasing resistance to treatments highlighting the urgent need for new strategies. Malaria parasites rely on the hexosamine biosynthetic pathway to produce UDP-N-acetylglucosamine, an essential metabolite for glycosylphosphatidylinositol synthesis. Glycosylphosphatidylinositol molecules anchor vital proteins to the parasites surface and, as free glycolipids, serve as structural components of its membranes. Our study examined the effects of disrupting PfGNA1, a key enzyme in the hexosamine biosynthetic pathway, which is distinct from its human counterparts. Disruption of PfGNA1 blocked the production of glycosylphosphatidylinositol, leading to improper protein localization, developmental arrest, and failure of the parasites to mature or exit infected red blood cells. Our results underscore the central role of the hexosamine biosynthetic pathway and glycosylphosphatidylinositol biosynthesis, which are essential for parasite survival. This pathway represents a promising target for developing novel antimalarial therapies.

microbiology↗

bioRxiv2022

Stepwise remodelling and subcompartment formation in individual vesicles by three ESCRT-III proteins

The endosomal sorting complex required for transport (ESCRT) is a multi-protein complex involved in several membrane remodelling processes. Different approaches have been used to dissect the mechanism by which ESCRT proteins produce scission in the membranes. However, the underlying mechanisms generating the membrane deformations remain poorly understood. In this study, giant unilamellar vesicles (GUVs), microfluidic technology and micropipette aspiration are combined to continuously follow the ESCRT-III-mediated membrane remodelling on the single-vesicle level for the first time. With this approach, we identify different mechanisms by which a minimal set of three ESCRT-III proteins from the phagocytic parasite Entamoeba histolytica reshape the membrane. These proteins modulate the membrane stiffness and spontaneous curvature to regulate the bud size and generate intraluminal vesicles in GUVs even in the absence of ATP. We show that the bud stability depends on the protein concentration and membrane tension. The approach introduced here should open the road to diverse applications in synthetic biology for establishing artificial cells with several membrane compartments.

biophysics↗

bioRxiv2020

The ESCRT-III machinery participates in the production of extracellular vesicles and protein export during Plasmodium falciparum infection

Infection with Plasmodium falciparum enhances extracellular vesicles (EVs) production in parasitized red blood cells (pRBC), an important mechanism for parasite-to-parasite communication during the asexual intraerythrocytic life cycle. The endosomal sorting complex required for transport (ESCRT), and in particular the ESCRT-III sub-complex, participates in the formation of EVs in higher eukaryotes. However, RBCs have lost the majority of their organelles through the maturation process, including an important reduction in their vesicular network. Therefore, the mechanism of EV production in P. falciparum-infected RBCs remains to be elucidated. Here we demonstrate that P. falciparum possesses a functional ESCRT-III machinery that is activated by an alternative recruitment pathway involving the action of PfBro1 and PfVps32/PfVps60 proteins. Additionally, multivesicular bodies formation and membrane shedding, both reported mechanisms of EVs production, were reconstituted in the membrane model of giant unilamellar vesicles using the purified recombinant proteins. Moreover, the presence of PfVps32, PfVps60 and PfBro1 in EVs purified from a pRBC culture was confirmed by super-resolution microscopy. In accordance, disruption of the Pfvps60 gene led to a reduction in the number of the produced EVs in the KO strain when compared with the parental 3D7 strain. Overall, our results increase the knowledge on the underlying molecular mechanisms during malaria pathogenesis and demonstrate that ESCRT-III P. falciparum proteins participate in EVs production.

microbiology↗