Biology subjects

Castro-Pena, C.

Publications and source records attributed to Castro-Pena, C..

3 recordsLinked to original sources

bioRxiv2024

Malaria parasite HOPS/CORVET complexes are critical for endocytosis and invasion organelles function

The tethering complexes HOPS/CORVET are central for vesicular fusion through the eukaryotic endolysosomal system, but the functions of these complexes in the intracellular development of malaria parasites are unknown. Here we show that early inactivation of core HOPS/CORVET complex subunits in Plasmodium falciparum leads to developmental arrest and accumulation of cytosolic vesicles, indicating a role of HOPS/CORVET in parasite endocytosis and fusion of endosomes to the digestive vacuole membrane. Late inactivation of the core HOPS/CORVET subunits led to the mislocalization of luminal rhoptry and microneme proteins, and to a severe defect in merozoite invasion. Ultra-expansion microscopy revealed a reduced rhoptry volume and the accumulation of numerous vesicles, further supporting a role of HOPS/CORVET in protein trafficking to the apical organelles. Malaria parasites have therefore repurposed HOPS/CORVET to perform dual functions consistent with a canonical endocytosis pathway for delivery of host cell material to the digestive vacuole in trophozoite stages and a parasite specific role in trafficking of protein cargo to the apical organelles required for invasion in schizont stages.

cell biology↗

bioRxiv2024

A system for functional studies of the major virulence factor of malaria parasites

PfEMP1 is a variable antigen displayed on erythrocytes infected with the malaria parasite Plasmodium falciparum. PfEMP1 mediates binding of the infected cell to the endothelium of blood vessels, a cause of severe malaria. Each parasite encodes [~]60 different PfEMP1 variants but only one is expressed at a time. Switching between variants underlies immune evasion in the host and variant-specific severity of disease. PfEMP1 is difficult to study due to expression heterogeneity between parasites which also renders genetic modification approaches ineffective. Here, we used selection linked integration (SLI) to generate parasites all expressing the same PfEMP1 variant and genome edit the expressed locus. Moving this system from the reference strain 3D7 to IT4 resulted in PfEMP1 expressor parasites with effective receptor binding capacities. We also introduce a second version of SLI (SLI2) to introduce additional genome edits. Using these systems, we study PfEMP1 trafficking, generate cell lines binding to the most common endothelial receptors, survey the protein environment from functional PfEMP1 in the host cell and identify new proteins needed for PfEMP1 mediated sequestration. These findings show the usefulness of the system to study the key virulence factor of malaria parasites.

microbiology↗

bioRxiv2022

The Kelch13 compartment is a hub of highly divergent vesicle trafficking proteins in malaria parasites

Single amino acid changes in the parasite protein Kelch13 (K13) result in reduced susceptibility of P. falciparum parasites to artemisinin and its derivatives (ART). Recent work indicated that K13 and other proteins co-localising with K13 (K13 compartment proteins) are involved in the endocytic uptake of host cell cytosol (HCCU) and that a reduction in HCCU results in ART resistance. HCCU is critical for parasite survival but is poorly understood, with the K13 compartment proteins among the few proteins so far functionally linked to this process. Here we further defined the composition of the K13 compartment by analysing more hits from a previous BioID, showing that MyoF and MCA2 as well as Kelch13 interaction candidate (KIC) 11 and 12 are found at this site. Functional analyses, tests for ART susceptibility as well as comparisons of structural similarities using AlphaFold2 predictions of these and previously identified proteins showed that canonical vesicle trafficking and endocytosis domains were frequent in proteins involved in resistance or endocytosis (or both), comprising one group of K13 compartment proteins. While this strengthened the link of the K13 compartment to endocytosis, many proteins of this group showed unusual domain combinations and large parasite-specific regions, indicating a high level of taxon-specific adaptation of this process. Another group of K13 compartment proteins did not influence endocytosis or ART susceptibility and lacked detectable vesicle trafficking domains. We here identified the first protein of this group that is important for asexual blood stage development and showed that it likely is involved in invasion. Overall, this work identified novel proteins functioning in endocytosis and at the K13 compartment. Together with comparisons of structural predictions it provides a repertoire of functional domains at the K13 compartment that indicate a high level of adaption of endocytosis in malaria parasites.

cell biology↗