scholarly journals A Bacterial Phosphatase-Like Enzyme of the Malaria Parasite Plasmodium falciparum Possesses Tyrosine Phosphatase Activity and Is Implicated in the Regulation of Band 3 Dynamics during Parasite Invasion

2013 ◽  
Vol 12 (9) ◽  
pp. 1179-1191 ◽  
Author(s):  
Sebastian Fernandez-Pol ◽  
Zdenek Slouka ◽  
Souvik Bhattacharjee ◽  
Yana Fedotova ◽  
Stefan Freed ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Phosphatase Activity ◽  
Tyrosine Phosphatase ◽  
Protein Band ◽  
Band 3 ◽  
Dense Granule ◽  
Content Type ◽  
Cytoskeletal Network ◽  
Parasite Plasmodium Falciparum

ABSTRACT Eukaryotic parasites of the genus Plasmodium cause malaria by invading and developing within host erythrocytes. Here, we demonstrate that PfShelph2, a gene product of Plasmodium falciparum that belongs to the Shewanella -like phosphatase (Shelph) subfamily, selectively hydrolyzes phosphotyrosine, as shown for other previously studied Shelph family members. In the extracellular merozoite stage, PfShelph2 localizes to vesicles that appear to be distinct from those of rhoptry, dense granule, or microneme organelles. During invasion, PfShelph2 is released from these vesicles and exported to the host erythrocyte. In vitro , PfShelph2 shows tyrosine phosphatase activity against the host erythrocyte protein Band 3, which is the most abundant tyrosine-phosphorylated species of the erythrocyte. During P. falciparum invasion, Band 3 undergoes dynamic and rapid clearance from the invasion junction within 1 to 2 s of parasite attachment to the erythrocyte. Release of Pfshelph2 occurs after clearance of Band 3 from the parasite-host cell interface and when the parasite is nearly or completely enclosed in the nascent vacuole. We propose a model in which the phosphatase modifies Band 3 in time to restore its interaction with the cytoskeleton and thus reestablishes the erythrocyte cytoskeletal network at the end of the invasion process.

scholarly journals Porphyromonas gingivalis Tyrosine Phosphatase Php1 Promotes Community Development and Pathogenicity

mBio ◽  
2019 ◽  
Vol 10 (5) ◽  
Author(s):  
Young-Jung Jung ◽  
Daniel P. Miller ◽  
John D. Perpich ◽  
Zackary R. Fitzsimonds ◽  
Daonan Shen ◽  
...  
Keyword(s):  
Community Development ◽  
Phosphatase Activity ◽  
Tyrosine Phosphorylation ◽  
Porphyromonas Gingivalis ◽  
Tyrosine Phosphatase ◽  
Protein Tyrosine Phosphorylation ◽  
Tyrosine Phosphatases ◽  
Content Type ◽  
Protein Tyrosine

ABSTRACT Protein-tyrosine phosphorylation in bacteria plays a significant role in multiple cellular functions, including those related to community development and virulence. Metal-dependent protein tyrosine phosphatases that belong to the polymerase and histindinol phosphatase (PHP) family are widespread in Gram-positive bacteria. Here, we show that Porphyromonas gingivalis, a Gram-negative periodontal pathogen, expresses a PHP protein, Php1, with divalent metal ion-dependent tyrosine phosphatase activity. Php1 tyrosine phosphatase activity was attenuated by mutation of conserved histidine residues that are important for the coordination of metal ions and by mutation of a conserved arginine residue, a key residue for catalysis in other bacterial PHPs. The php1 gene is located immediately downstream of the gene encoding the bacterial tyrosine (BY) kinase Ptk1, which was a substrate for Php1 in vitro. Php1 rapidly caused the conversion of Ptk1 to a state of low tyrosine phosphorylation in the absence of discernible intermediate phosphoforms. Active Php1 was required for P. gingivalis exopolysaccharide production and for community development with the antecedent oral biofilm constituent Streptococcus gordonii under nutrient-depleted conditions. In contrast, the absence of Php1 had no effect on the ability of P. gingivalis to form monospecies biofilms. In vitro, Php1 enzymatic activity was resistant to the effects of the streptococcal secreted metabolites pABA and H2O2, which inhibited Ltp1, an enzyme in the low-molecular-weight (LMW) phosphotyrosine phosphatase family. Ptk1 reciprocally phosphorylated Php1 on tyrosine residues 159 and 161, which independently impacted phosphatase activity. Loss of Php1 rendered P. gingivalis nonvirulent in an animal model of periodontal disease. Collectively, these results demonstrate that P. gingivalis possesses active PHP and LMW tyrosine phosphatases, a unique configuration in Gram-negatives which may allow P. gingivalis to maintain phosphorylation/dephosphorylation homeostasis in multispecies communities. Moreover, Php1 contributes to the pathogenic potential of the organism. IMPORTANCE Periodontal diseases are among the most common infections of humans and are also associated with systemic inflammatory conditions. Colonization and pathogenicity of P. gingivalis are regulated by signal transduction pathways based on protein tyrosine phosphorylation and dephosphorylation. Here, we identify and characterize a novel component of the tyrosine (de)phosphorylation axis: a polymerase and histindinol phosphatase (PHP) family enzyme. This tyrosine phosphatase, designated Php1, was required for P. gingivalis community development with other oral bacteria, and in the absence of Php1 activity P. gingivalis was unable to cause disease in a mouse model of periodontitis. This work provides significant insights into the protein tyrosine (de)phosphorylation network in P. gingivalis, its adaptation to heterotypic communities, and its contribution to colonization and virulence.

Cytoadherence-related neoantigens on Plasmodium falciparum (human malaria)-infected human erythrocytes result from the exposure of normally cryptic regions of the band 3 protein

Parasitology ◽  
1994 ◽  
Vol 108 (3) ◽  
pp. 257-267 ◽  
Author(s):  
I. Crandall ◽  
I. W. Sherman
Keyword(s):  
Plasmodium Falciparum ◽  
Protein Band ◽  
Band 3 ◽  
Amelanotic Melanoma ◽  
Red Cells ◽  
Sequence Motif ◽  
Red Cell ◽  
Band 3 Protein ◽  
Red Cell Membranes

SUMMARYMurine monoclonal antibodies (Mabs) were produced by vaccination of Balb/c mice with live Plasmodium falciparum infected red cells (iRBC). The iRBC Mabs recognized altered forms of the human erythrocyte membrane protein band 3; however, these Mabs did not recognize the band 3 molecule in uninfected or ring-infected red cells. The location of epitopes was determined by studying the binding of the iRBC Mabs after selective proteolysis of band 3 as well as by the reactivity of these Mabs to synthetic peptides that corresponded to putative exofacial regions of band 3. Treatment of uninfected red cell membranes with trypsin under low ionic strength conditions resulted in exposure of cryptic epitopes of band 3 which were recognized by the iRBC Mabs. Several of the anti-iRBC Mabs (two of which were described previously) inhibited the in vitro adherence of infected erythrocytes to C32 amelanotic melanoma cells. A mouse polyclonal serum against a synthetic peptide based on an amino acid sequence motif of band 3 reacted (by immunostaining) only with the surface of iRBC and blocked adhesion. Thus, it appears that cryptic residues of the band 3 protein become exposed upon parasitization, and their presence contributes to the increased adhesiveness of the P. falciparum-infected red cell.

scholarly journals Localization of ferrochelatase in Plasmodium falciparum

2004 ◽  
Vol 384 (2) ◽  
pp. 429-436 ◽  
Author(s):  
Sundaramurthy VARADHARAJAN ◽  
B. K. Chandrashekar SAGAR ◽  
Pundi N. RANGARAJAN ◽  
Govindarajan PADMANABAN
Keyword(s):  
Plasmodium Falciparum ◽  
De Novo ◽  
Enzymic Activity ◽  
Malarial Parasite ◽  
Parasite Genome ◽  
Marker Proteins ◽  
Parasite Plasmodium ◽  
Theoretical Predictions ◽  
Parasite Plasmodium Falciparum

Our previous studies have demonstrated de novo haem biosynthesis in the malarial parasite (Plasmodium falciparum and P. berghei). It has also been shown that the first enzyme of the pathway is the parasite genome-coded ALA (δ-aminolaevulinate) synthase localized in the parasite mitochondrion, whereas the second enzyme, ALAD (ALA dehydratase), is accounted for by two species: one species imported from the host red blood cell into the parasite cytosol and another parasite genome-coded species in the apicoplast. In the present study, specific antibodies have been raised to PfFC (parasite genome-coded ferrochelatase), the terminal enzyme of the haem-biosynthetic pathway, using recombinant truncated protein. With the use of these antibodies as well as those against the hFC (host red cell ferrochelatase) and other marker proteins, immunofluorescence studies were performed. The results reveal that P. falciparum in culture manifests a broad distribution of hFC and a localized distribution of PfFC in the parasite. However, PfFC is not localized to the parasite mitochondrion. Immunoelectron-microscopy studies reveal that PfFC is indeed localized to the apicoplast, whereas hFC is distributed in the parasite cytoplasm. These results on the localization of PfFC are unexpected and are at variance with theoretical predictions based on leader sequence analysis. Biochemical studies using the parasite cytosolic and organellar fractions reveal that the cytosol containing hFC accounts for 80% of FC enzymic activity, whereas the organellar fraction containing PfFC accounts for the remaining 20%. Interestingly, both the isolated cytosolic and organellar fractions are capable of independent haem synthesis in vitro from [4-14C]ALA, with the cytosol being three times more efficient compared with the organellar fraction. With [2-14C]glycine, most of the haem is synthesized in the organellar fraction. Thus haem is synthesized in two independent compartments: in the cytosol, using the imported host enzymes, and in the organellar fractions, using the parasite genome-coded enzymes.

Two chicken erythrocyte band 3 mRNAs are generated by alternative transcriptional initiation and differential RNA splicing

1989 ◽  
Vol 9 (11) ◽  
pp. 5198-5206
Author(s):  
H R Kim ◽  
B S Kennedy ◽  
J D Engel
Keyword(s):  
Rna Splicing ◽  
Single Gene ◽  
Protein Band ◽  
Band 3 ◽  
Chicken Erythrocyte ◽  
Cellular Functions ◽  
Transcriptional Initiation ◽  
Extracellular Milieu ◽  
Cytoskeletal Network ◽  
Anion Transporter

The erythrocyte anion transport protein (band 3) mediates two distinct cellular functions: it provides plasma membrane attachment sites for the erythroid cytoskeletal network, and it also functions as the anion transporter between the erythrocyte cytoplasm and extracellular milieu. We previously showed that two chicken band 3 polypeptides are encoded by two different mRNAs with different translation initiation sites. Here we show that these two band 3 mRNAs are transcribed from two separate promoters within a single gene. In addition, the two pre-mRNAs are differentially spliced, leading to fusion with coding exons used in common in the two mRNAs. The chicken erythrocyte band 3 gene is therefore the first example of a gene that has two promoters within a single locus which function equally efficiently in one cell type at the same developmental stage.

scholarly journals Effect of Fluorescent Dyes onIn Vitro-Differentiated, Late-Stage Plasmodium falciparum Gametocytes

2014 ◽  
Vol 58 (12) ◽  
pp. 7398-7404 ◽  
Author(s):  
Tamirat Gebru ◽  
Benjamin Mordmüller ◽  
Jana Held
Keyword(s):  
Plasmodium Falciparum ◽  
Late Stage ◽  
Fluorescent Dyes ◽  
Clinical Symptoms ◽  
Laboratory Strain ◽  
Clinical Isolates ◽  
Synthetic Dyes ◽  
Content Type ◽  
Highly Active

ABSTRACTPlasmodium falciparumgametocytes are not associated with clinical symptoms, but they are responsible for transmitting the pathogen to mosquitoes. Therefore, gametocytocidal interventions are important for malaria control and resistance containment. Currently available drugs and vaccines are not well suited for that purpose. Several dyes have potent antimicrobial activity, but their use against gametocytes has not been investigated systematically. The gametocytocidal activity of nine synthetic dyes and four control compounds was tested against stage V gametocytes of the laboratory strain 3D7 and three clinical isolates ofP. falciparumwith a bioluminescence assay. Five of the fluorescent dyes had submicromolar 50% inhibitory concentration (IC50) values against mature gametocytes. Three mitochondrial dyes, MitoRed, dihexyloxacarbocyanine iodide (DiOC6), and rhodamine B, were highly active (IC50s < 200 nM). MitoRed showed the highest activity against gametocytes, with IC50s of 70 nM against 3D7 and 120 to 210 nM against clinical isolates. All compounds were more active against the laboratory strain 3D7 than against clinical isolates. In particular, the endoperoxides artesunate and dihydroartemisinin showed a 10-fold higher activity against 3D7 than against clinical isolates. In contrast to all clinically used antimalarials, several fluorescent dyes had surprisingly highin vitroactivity against late-stage gametocytes. Since they also act against asexual blood stages, they shall be considered starting points for the development of new antimalarial lead compounds.

scholarly journals Plasmodium falciparum Line-Dependent Association ofIn VitroGrowth-Inhibitory Activity and Risk of Malaria

2012 ◽  
Vol 80 (5) ◽  
pp. 1900-1908 ◽  
Author(s):  
Josea Rono ◽  
Anna Färnert ◽  
Daniel Olsson ◽  
Faith Osier ◽  
Ingegerd Rooth ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Inhibitory Activity ◽  
Content Type ◽  
Phenotypic Differences ◽  
Erythrocyte Invasion ◽  
Growth Inhibitory ◽  
Growth Inhibitory Activity ◽  
Control Study

ABSTRACTPlasmodium falciparum's ability to invade erythrocytes is essential for its survival within the human host. Immune mechanisms that impair this ability are therefore expected to contribute to immunity against the parasite. Plasma of humans who are naturally exposed to malaria has been shown to have growth-inhibitory activity (GIA)in vitro. However, the importance of GIA in relation to protection from malaria has been unclear. In a case-control study nested within a longitudinally followed population in Tanzania, plasma samples collected at baseline from 171 individuals (55 cases and 116 age-matched controls) were assayed for GIA using threeP. falciparumlines (3D7, K1, and W2mef) chosen based on their erythrocyte invasion phenotypes. Distribution of GIA differed between the lines, with most samples inhibiting the growth of 3D7 and K1 and enhancing the growth of W2mef. GIA to 3D7 was associated with a reduced risk of malaria within 40 weeks of follow-up (odds ratio, 0.45; 95% confidence interval [CI], 0.21 to 0.96;P= 0.04), whereas GIA to K1 and W2mef was not. These results show that GIA, as well as its association with protection from malaria, is dependent on theP. falciparumline and can be explained by differences in erythrocyte invasion phenotypes between parasite lines. Our study contributes knowledge on the biological importance of growth inhibition and the potential influence ofP. falciparumerythrocyte invasion phenotypic differences on its relationship to protective immunity against malaria.

scholarly journals A Chemical Rescue Screen Identifies a Plasmodium falciparum Apicoplast Inhibitor Targeting MEP Isoprenoid Precursor Biosynthesis

2014 ◽  
Vol 59 (1) ◽  
pp. 356-364 ◽  
Author(s):  
Wesley Wu ◽  
Zachary Herrera ◽  
Danny Ebert ◽  
Katie Baska ◽  
Seok H. Cho ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Antimalarial Drug ◽  
Drug Targets ◽  
Specific Activity ◽  
Drug Candidate ◽  
Content Type ◽  
Chemical Rescue ◽  
Growth Inhibitory ◽  
Parasite Populations

ABSTRACTThe apicoplast is an essential plastid organelle found inPlasmodiumparasites which contains several clinically validated antimalarial-drug targets. A chemical rescue screen identified MMV-08138 from the “Malaria Box” library of growth-inhibitory antimalarial compounds as having specific activity against the apicoplast. MMV-08138 inhibition of blood-stagePlasmodium falciparumgrowth is stereospecific and potent, with the most active diastereomer demonstrating a 50% effective concentration (EC50) of 110 nM. Whole-genome sequencing of 3 drug-resistant parasite populations from two independent selections revealed E688Q and L244I mutations inP. falciparumIspD, an enzyme in the MEP (methyl-d-erythritol-4-phosphate) isoprenoid precursor biosynthesis pathway in the apicoplast. The active diastereomer of MMV-08138 directly inhibited PfIspD activityin vitrowith a 50% inhibitory concentration (IC50) of 7.0 nM. MMV-08138 is the first PfIspD inhibitor to be identified and, together with heterologously expressed PfIspD, provides the foundation for further development of this promising antimalarial drug candidate lead. Furthermore, this report validates the use of the apicoplast chemical rescue screen coupled with target elucidation as a discovery tool to identify specific apicoplast-targeting compounds with new mechanisms of action.

Sign in / Sign up

Export Citation Format

Share Document