APlasmodiumα/β-hydrolase modulates the development of invasive stages

Abstract

The bud emergence (BEM)46 proteins are evolutionarily conserved members of the α/β-hydrolase superfamily, which includes enzymes with diverse functions and a wide range of substrates. Here, we identified a Plasmodium BEM46-like protein (PBLP) and characterized it throughout the life cycle of the rodent malaria parasite Plasmodium yoelii. The Plasmodium BEM46-like protein is shown to be closely associated with the parasite plasma membrane of asexual erythrocytic stage schizonts and exo-erythrocytic schizonts; however, PBLP localizes to unique intracellular structures in sporozoites. Generation and analysis of P. yoelii knockout (Δpblp) parasite lines showed that PBLP has an important role in erythrocytic stage merozoite development with Δpblp parasites forming fewer merozoites during schizogony, which results in decreased parasitemia when compared with wild-type (WT) parasites. Δpblp parasites showed no defects in gametogenesis or transmission to mosquitoes; however, because they formed fewer oocysts there was a reduction in the number of developed sporozoites in infected mosquitoes when compared with WT. Although Δpblp sporozoites showed no apparent defect in mosquito salivary gland infection, they showed decreased infectivity in hepatocytes in vitro. Similarly, mice infected with Δpblp sporozoites exhibited a delay in the onset of blood-stage patency, which is likely caused by reduced sporozoite infectivity and a discernible delay in exo-erythrocytic merozoite formation. These data are consistent with the model that PBLP has an important role in parasite invasive-stage morphogenesis throughout the parasite life cycle.

The transcriptome of the mosquito Aedes fluviatilis (Diptera: Culicidae), and transcriptional changes associated with its native Wolbachia infection

“…Some galactose-specific c-type lectins are highly differentially expressed by Wolbachia [11], their expression is stimulated by Plasmodium infection, and they have been shown to protect Plasmodium against melanisation by the host immune system [49]. There are also examples of mucin like genes and cell wall hydrolases that are critical to Plasmodium development in mosquitoes [50, 51]. …”

Discovery of four new B-cell protective epitopes for malaria using Q beta virus-like particle as platform

“… Protein Accession no. Initial description Evidence for role in liver-stage infectivity and as vaccine PBLP Plasmodium BEM46-like protein A0A113RBV9 41 41 SSP3 sporozoite surface protein 3 PBANKA_1425200 42 42 SIAP 1 sporozoite invasion-associated protein 1 PBANKA_1006200 43 43 , 44 Maebl merozoite adhesive erythrocytic binding protein PBANKA_0901300.2 45 46 – 49 RON4 rhoptry neck protein 4 PBANKA_0932000 50 51 P113 surface protein P113 PBANKA_1022500 52 53 PLP1 sporozoite micronemal protein essential for cell traversal PBANKA_1006300 54 55 – 57 RON3 rhoptry neck protein 3 PBANKA_1464900 58 none a Falstatin PBANKA_0813000 59 60 – 62 TRSP Thrombospondin-related sporozoite protein A1X5V6-1 63 64 a Evidence only for RON3 surface expression on sporozoites 19 . …”

Functional annotation of serine hydrolases in the asexual erythrocytic stage of Plasmodium falciparum

“…Proteins are listed in order of ID. S, soluble; I, insoluble; db-FP, desthiobiotin-FP.ID PF3D7_Name/PlasmoDB Annotation a Mass (kDa) b FractionUnique PeptidesConfidenceTn insertion c db-FPno probe Serine hydrolase superfamily 0209100Patatin-like phospholipase, putative78.3S1, 3, 20, 0, 0mediumyes0218600Patatin-like phospholipase, putative284I18, 16, 400, 0, 0highyes d 0301300Epoxide hydrolase 1 17 50.5I7, 6, 70, 0, 0highyes0321500Peptidase, putative126I22, 19, 280, 0, 0highyesS3, 3, 100, 0, 1high0403800Alpha/beta hydrolase, putative83.4I7, 7, 140, 0, 0highno0506900Rhomboid protease ROM4 19 86.7I4, 4, 20, 0, 0mediumno0629300Phospholipase 15 99.2I2, 2, 90, 0, 0mediumno0709700Prodrug activation and resistance esterase 24 42.4I16, 14, 160, 0, 0highyes0728700Alpha/beta hydrolase, putative84.8I2, 2, 50, 0, 0mediumno0818600Plasmodium BEM46-like protein 18 34.9I4, 3, 100, 0, 0highno1001600Exported lipase 2 17 88.6S2, 6, 120, 0, 0mediumnoI5, 2, 80, 0, 0medium1120400Alpha/beta hydrolase...…”

“…The ten serine hydrolases without reported transposon insertions represent putatively essential proteins for asexual replication of P. falciparum . Only four have been previously characterized at a biochemical and/or cellular level in any Plasmodium species: PF3D7_0629300, an ortholog of a P. berghei phospholipase that contributes to effective sporozoite migration 15 and merozoite egress from hepatocytes 16 ; PF3D7_1001600, termed “exported lipase 2” based on sequence homology and exported into the host erythrocyte 17 ; PF3D7_0818600, an ortholog of P. berghei BEM46-like protein that influences merozoite development in erythrocytes and sporozoite development in oocysts 18 ; and rhomboid protease ROM4, which is responsible for shedding adhesins from the surface of invasive parasite forms 19,20 .…”

“…Seven candidate lipases fulfilled these criteria, six of which exhibited a complete or near-complete disappearance of unique peptides from the IDFP-treated samples (Table 3). These six include “prodrug activation and resistance esterase” (PfPARE), an enzyme that can catalyse the hydrolysis of pepstatin esters but has no known physiological substrate 24 , BEM46-like protein 18 also with no known physiological substrate, and four uncharacterized enzymes. The seventh enzyme, exported lipase 2 17 , exhibited modest decreases in unique peptide numbers and T3PQ ratios, which together suggest partial inhibition by IDFP.…”