A Hetero-Multimeric Chitinase-Containing Plasmodium falciparum and Plasmodium gallinaceum Ookinete-Secreted Protein Complex Involved in Mosquito Midgut Invasion

Patra, Kailash P.; Kaur, Harpreet; Kolli, Surendra Kumar; Wozniak, Jacob M.; Prieto, Judith Helena; Yates, John R.; Gonzalez, David J.; Janse, Chris J.; Vinetz, Joseph M.

doi:10.3389/fcimb.2020.615343

Cited by 4 publications

(18 citation statements)

References 74 publications

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“…This pivotal degradation process is normally carried out by a chitinase secreted by the parasite. Interestingly, chitinase inhibitors and anti-chitinase antibodies are known to reduce parasite transmission from the vertebrate host to the mosquito, thus suggesting that the peritrophic matrix chitin is a critical feature related to Plasmodium penetration of the midgut [45][46][47]. Considering the major roles of chitinases in the crucial processes of the Plasmodium invasion, it is reasonable to presume that genetic variants of mosquito chitinases can be responsible for the integrity and variable thicknesses of the PM.…”

Section: Discussionmentioning

confidence: 99%

Susceptibility of Field-Collected Nyssorhynchus darlingi to Plasmodium spp. in Western Amazonian Brazil

Alonso

Alvarez

Ribolla

et al. 2021

Genes

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Mosquito susceptibility to Plasmodium spp. infection is of paramount importance for malaria occurrence and sustainable transmission. Therefore, understanding the genetic features underlying the mechanisms of susceptibility traits is pivotal to assessing malaria transmission dynamics in endemic areas. The aim of this study was to investigate the susceptibility of Nyssorhynchus darlingi—the dominant malaria vector in Brazil—to Plasmodium spp. using a reduced representation genome-sequencing protocol. The investigation was performed using a genome-wide association study (GWAS) to identify mosquito genes that are predicted to modulate the susceptibility of natural populations of the mosquito to Plasmodium infection. After applying the sequence alignment protocol, we generated the variant panel and filtered variants; leading to the detection of 202,837 SNPs in all specimens analyzed. The resulting panel was used to perform GWAS by comparing the pool of SNP variants present in Ny. darlingi infected with Plasmodium spp. with the pool obtained in field-collected mosquitoes with no evidence of infection by the parasite (all mosquitoes were tested separately using RT-PCR). The GWAS results for infection status showed two statistically significant variants adjacent to important genes that can be associated with susceptibility to Plasmodium infection: Cytochrome P450 (cyp450) and chitinase. This study provides relevant knowledge on malaria transmission dynamics by using a genomic approach to identify mosquito genes associated with susceptibility to Plasmodium infection in Ny. darlingi in western Amazonian Brazil.

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Section: Discussionmentioning

confidence: 99%

Susceptibility of Field-Collected Nyssorhynchus darlingi to Plasmodium spp. in Western Amazonian Brazil

Alonso

Alvarez

Ribolla

et al. 2021

Genes

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“…Fetal bovine serum (FBS) was used as positive control, as it is known to have demonstrated chitinase activity. 11 The purified rPfCHT1-220, À230, and -Triple mutant did not show any measurable chitinase enzymatic activity. However, the elution peaks in the affinity purification chromatograms were observed for -Triple, and À230 mutant proteins (Figure S2).…”

Section: Pfcht1-203 Cysteine Is Highly Reactive and Leads To The Form...mentioning

confidence: 91%

“…In escaping the mosquito midgut, the role played by the Plasmodium ookinete‐secreted chitinases varies among Plasmodium species 10 . However, both long and short chitinase forms bind to chitin have been well demonstrated irrespective of the structural differences of the Plasmodium chitinase protein 11 . Structurally, Plasmodium species with long chitinases have four conserved cysteine residues in the chitin‐binding domain at the C‐terminal compared to the three conserved cysteine residues located in the catalytic domain of the short chitinases 10 .…”

Section: Introductionmentioning

confidence: 99%

Structure–function analysis of cysteine residues in the plasmodium falciparum chitinase, PfCHT1

et al. 2022

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The Plasmodium ookinete uses chitinase activity to penetrate the acellular, chitin-containing peritrophic matrix to invade the mosquito vector. Plasmodium ookinetes from different parasite clades secrete two structurally distinct forms of chitinase, one, a short form lacking a C-terminal putative chitinbinding domain (CBD), the other, a long form with both proenzyme and C-terminal putative chitin-binding domains. Here, we structurally and functionally characterize the three cysteines in the short chitinase of the humaninfecting malaria parasite, P. falciparum testing the hypothesis that one unpaired cysteine would not contribute to chitinase-specific enzymatic activity which would identify this residue as potentially involved in intermolecular disulfide bonding and heteromultimeric invasion complex formation as previously described. To test this hypothesis, we produced and characterized recombinant wild-type and cysteine-mutation PfCHT1 proteins in E. coli and used biophysical and enzymatic approaches to examine their enzymatic activities and chitin-binding affinities. The cysteine-203 PfCHT1 mutation had no effect on chitinolytic and chitin-binding functions. The cysteine-220 and cysteine-230 mutants were enzymatically inactive and did not bind to chitin. The artificial intelligence-based protein prediction algorithm, AlphaFold, correctly identified the involvement of cys-220 and cys-230 in the intramolecular disulfide linkages key to maintaining properly folded chitinase structural integrity. AlphaFold predicted that cys-203 cysteine is surface exposed and thus involved in intermolecular protein-protein interaction. Production of the cys-to-ser 203 PfCHT1 mutant facilitated recombinant protein production. Future cellular and biochemical studies are needed to further understand details of Plasmodium ookinete mosquito midgut invasion.

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“…A recent report showed that PgCHT2 and its ortholog PfCHT1 form high-molecular weight (HMW) complexes, the implications of which are unknown. 58 Sequence alignment of four representative long forms (PvCHT1, PbCHT1, PreCHT1, and PgCHT1) or four short forms (PgCHT2, PfCHT1, PrCHT1, and PreCHT2), lead to the construction of a consensus-like signature sequence for the long and short forms. When the consensus sequence belonging to the long and short forms were aligned, some of the positions were not invariant (Figure 3).…”

Section: Properties Of Plasmodium Chitinasesmentioning

confidence: 99%

“…This regulation is dialed out in short forms along probably compensated with high specific activity. A recent report showed that PgCHT2 and its ortholog PfCHT1 form high‐molecular weight (HMW) complexes, the implications of which are unknown 58 …”

Section: Properties Of Plasmodium Chitinasesmentioning

confidence: 99%

Plasmodium chitinases: revisiting a target of transmission‐blockade against malaria

et al. 2021

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Malaria is a life-threatening disease caused by one of the five species of Plasmodium, among which Plasmodium falciparum cause the deadliest form of the disease. Plasmodium species are dependent on a vertebrate host and a bloodsucking insect vector to complete their life cycle. Plasmodium chitinases belonging to the GH18 family are secreted inside the mosquito midgut, during the ookinete stage of the parasite. Chitinases mediate the penetration of parasite through the peritrophic membrane, facilitating access to the gut epithelial layer. In this review, we describe Plasmodium chitinases with special emphasis on chitinases from P. falciparum and P. vivax, the representative examples of the short and long forms of this protein. In addition to the chitinase domain, chitinases belonging to the long form contain a pro-domain and chitin-binding domain. Amino acid sequence alignment of long and short form chitinase domains reveals multiple positions containing variant residues. A subset of these positions was found to be conserved or invariant within long or short forms, indicating the role of these positions in attributing form-specific activity. The reported differences in affinities to allosamidin for P. vivax and P. falciparum were predicted to be due to different residues at two amino acid positions, resulting in altered interactions with the inhibitor. Understanding the role of these amino acids in Plasmodium chitinases will help us elucidate the mechanism of catalysis and the mode of inhibition, which will be the key for identification of potent inhibitors or antibodies demonstrating transmission-blocking activity.

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A Hetero-Multimeric Chitinase-Containing Plasmodium falciparum and Plasmodium gallinaceum Ookinete-Secreted Protein Complex Involved in Mosquito Midgut Invasion

Cited by 4 publications

References 74 publications

Susceptibility of Field-Collected Nyssorhynchus darlingi to Plasmodium spp. in Western Amazonian Brazil

Susceptibility of Field-Collected Nyssorhynchus darlingi to Plasmodium spp. in Western Amazonian Brazil

Structure–function analysis of cysteine residues in the plasmodium falciparum chitinase, PfCHT1

Plasmodium chitinases: revisiting a target of transmission‐blockade against malaria

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