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Proteomic profiling of Plasmodium sporozoite maturation identifies new proteins essential for parasite development and infectivity.

Lasonder E, Janse CJ, van Gemert GJ, Mair GR, Vermunt AM, Douradinha BG, van Noort V, Huynen MA, Luty AJ, Kroeze H, Khan SM, Sauerwein RW, Waters AP, Mann M, Stunnenberg HG - PLoS Pathog. (2008)

Bottom Line: The different sporozoite proteomes contain a large number of stage specific proteins whose annotation suggest an involvement in sporozoite maturation, motility, infection of the human host and associated metabolic adjustments.Analyses of proteins identified in the P. falciparum sporozoite proteomes by orthologous gene disruption in the rodent malaria parasite, P. berghei, revealed three previously uncharacterized Plasmodium proteins that appear to be essential for sporozoite development at distinct points of maturation in the mosquito.This study sheds light on the development and maturation of the malaria parasite in an Anopheles mosquito and also identifies proteins that may be essential for sporozoite infectivity to humans.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biology, NCMLS, Radboud University Nijmegen, Nijmegen, The Netherlands.

ABSTRACT
Plasmodium falciparum sporozoites that develop and mature inside an Anopheles mosquito initiate a malaria infection in humans. Here we report the first proteomic comparison of different parasite stages from the mosquito -- early and late oocysts containing midgut sporozoites, and the mature, infectious salivary gland sporozoites. Despite the morphological similarity between midgut and salivary gland sporozoites, their proteomes are markedly different, in agreement with their increase in hepatocyte infectivity. The different sporozoite proteomes contain a large number of stage specific proteins whose annotation suggest an involvement in sporozoite maturation, motility, infection of the human host and associated metabolic adjustments. Analyses of proteins identified in the P. falciparum sporozoite proteomes by orthologous gene disruption in the rodent malaria parasite, P. berghei, revealed three previously uncharacterized Plasmodium proteins that appear to be essential for sporozoite development at distinct points of maturation in the mosquito. This study sheds light on the development and maturation of the malaria parasite in an Anopheles mosquito and also identifies proteins that may be essential for sporozoite infectivity to humans.

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Gene Ontology term enrichment analysis of mosquito stage proteome.(A) Enrichment for GO ‘Biological Process’ terms of proteins detected in mosquito and blood stages. The figure shows terms on the x-axis that are significantly enriched (p<0.004) by more than four fold. GO terms of the shared set of proteins (n = 478, purple bars) is compared to terms of all predicted P. falciparum proteins (5410, green bars). The y-axis displays the fraction relative to all GO Biological Process terms. (B) Enrichment for GO ‘Molecular Function’ main terms of proteins detected specifically in mosquito stages (and blood stages). GO terms of the mosquito specific set of proteins (n = 250, blue bars) is compared terms of all predicted P. falciparum proteins (5410, green bars). The y-axis displays the fraction relative to all GO Molecular Function terms. These terms do not show a significant enrichment (p>0.5).
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ppat-1000195-g002: Gene Ontology term enrichment analysis of mosquito stage proteome.(A) Enrichment for GO ‘Biological Process’ terms of proteins detected in mosquito and blood stages. The figure shows terms on the x-axis that are significantly enriched (p<0.004) by more than four fold. GO terms of the shared set of proteins (n = 478, purple bars) is compared to terms of all predicted P. falciparum proteins (5410, green bars). The y-axis displays the fraction relative to all GO Biological Process terms. (B) Enrichment for GO ‘Molecular Function’ main terms of proteins detected specifically in mosquito stages (and blood stages). GO terms of the mosquito specific set of proteins (n = 250, blue bars) is compared terms of all predicted P. falciparum proteins (5410, green bars). The y-axis displays the fraction relative to all GO Molecular Function terms. These terms do not show a significant enrichment (p>0.5).

Mentions: A global functional characterization of the ‘mosquito stage’ proteome was performed by an enrichment analysis of Gene Ontology (GO) annotations, for both the proteins that are shared between blood stages and mosquito stages (n = 478) and for the mosquito stage specific proteins (n = 250). The set of 478 genes commonly expressed in both mosquito and blood stages showed enrichment in GO annotations in all classes (i.e. Molecular Function, Cellular Component and Biological process (Figure S1)) and this enrichment is principally associated with housekeeping genes (Figure 2). The mosquito stage specific proteome did not reveal significant (p<0.01) enrichment in GO annotations nor did additional analyses for GO enrichment of the mosquito stage specific proteins using BINGO [34] and Ontologizer [35] (data not shown). In Figure 2B GO categories (Molecular Function) are shown for the mosquito stage specific proteome that contain more than 5 proteins. The lack of enrichment could be caused by the high proportion of genes annotated as hypothetical (300 out of 728) and consequently the relatively large number of proteins in the mosquito stage specific proteome (124 out of 250) without a GO annotation. Since our analysis did not reveal a significant GO enrichment for proteins known to be important in sporozoite function (e.g. motility and motor activity (Figure 2)) we analyzed our mosquito stage proteome for previously reported proteins, for which a function during sporozoite development is described and supported by strong experimental evidence (e.g. gene-knockout and/or antibody-inhibition studies). These proteins, in total 23, are listed in Table 1 and 15 out of 23 proteins are present in the mosquito stage proteome reported here. Based on a total number of 5410 genes in the genome of P. falciparum and 728 proteins in our mosquito stage proteome, these 15 proteins represent a 4.8 fold functional enrichment relative to the annotated genome and is highly significant (p<0.001 using Ontologizer). A good agreement exists between the function of the sporozoite proteins as shown in Table 1 and their expression pattern in the different mosquito stages. For example, proteins with multiple roles during sporozoite maturation (e.g. CS and TRAP) were identified in all stages (OOC, ODS and SGS) whereas proteins involved in hepatocyte traversal, such as SPECT1, SPECT2 (sporozoite microneme protein essential for cell traversal 1 and 2) and CelTOS (cell-traversal protein for ookinetes and sporozoites) were exclusively identified in mature SGS.


Proteomic profiling of Plasmodium sporozoite maturation identifies new proteins essential for parasite development and infectivity.

Lasonder E, Janse CJ, van Gemert GJ, Mair GR, Vermunt AM, Douradinha BG, van Noort V, Huynen MA, Luty AJ, Kroeze H, Khan SM, Sauerwein RW, Waters AP, Mann M, Stunnenberg HG - PLoS Pathog. (2008)

Gene Ontology term enrichment analysis of mosquito stage proteome.(A) Enrichment for GO ‘Biological Process’ terms of proteins detected in mosquito and blood stages. The figure shows terms on the x-axis that are significantly enriched (p<0.004) by more than four fold. GO terms of the shared set of proteins (n = 478, purple bars) is compared to terms of all predicted P. falciparum proteins (5410, green bars). The y-axis displays the fraction relative to all GO Biological Process terms. (B) Enrichment for GO ‘Molecular Function’ main terms of proteins detected specifically in mosquito stages (and blood stages). GO terms of the mosquito specific set of proteins (n = 250, blue bars) is compared terms of all predicted P. falciparum proteins (5410, green bars). The y-axis displays the fraction relative to all GO Molecular Function terms. These terms do not show a significant enrichment (p>0.5).
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2570797&req=5

ppat-1000195-g002: Gene Ontology term enrichment analysis of mosquito stage proteome.(A) Enrichment for GO ‘Biological Process’ terms of proteins detected in mosquito and blood stages. The figure shows terms on the x-axis that are significantly enriched (p<0.004) by more than four fold. GO terms of the shared set of proteins (n = 478, purple bars) is compared to terms of all predicted P. falciparum proteins (5410, green bars). The y-axis displays the fraction relative to all GO Biological Process terms. (B) Enrichment for GO ‘Molecular Function’ main terms of proteins detected specifically in mosquito stages (and blood stages). GO terms of the mosquito specific set of proteins (n = 250, blue bars) is compared terms of all predicted P. falciparum proteins (5410, green bars). The y-axis displays the fraction relative to all GO Molecular Function terms. These terms do not show a significant enrichment (p>0.5).
Mentions: A global functional characterization of the ‘mosquito stage’ proteome was performed by an enrichment analysis of Gene Ontology (GO) annotations, for both the proteins that are shared between blood stages and mosquito stages (n = 478) and for the mosquito stage specific proteins (n = 250). The set of 478 genes commonly expressed in both mosquito and blood stages showed enrichment in GO annotations in all classes (i.e. Molecular Function, Cellular Component and Biological process (Figure S1)) and this enrichment is principally associated with housekeeping genes (Figure 2). The mosquito stage specific proteome did not reveal significant (p<0.01) enrichment in GO annotations nor did additional analyses for GO enrichment of the mosquito stage specific proteins using BINGO [34] and Ontologizer [35] (data not shown). In Figure 2B GO categories (Molecular Function) are shown for the mosquito stage specific proteome that contain more than 5 proteins. The lack of enrichment could be caused by the high proportion of genes annotated as hypothetical (300 out of 728) and consequently the relatively large number of proteins in the mosquito stage specific proteome (124 out of 250) without a GO annotation. Since our analysis did not reveal a significant GO enrichment for proteins known to be important in sporozoite function (e.g. motility and motor activity (Figure 2)) we analyzed our mosquito stage proteome for previously reported proteins, for which a function during sporozoite development is described and supported by strong experimental evidence (e.g. gene-knockout and/or antibody-inhibition studies). These proteins, in total 23, are listed in Table 1 and 15 out of 23 proteins are present in the mosquito stage proteome reported here. Based on a total number of 5410 genes in the genome of P. falciparum and 728 proteins in our mosquito stage proteome, these 15 proteins represent a 4.8 fold functional enrichment relative to the annotated genome and is highly significant (p<0.001 using Ontologizer). A good agreement exists between the function of the sporozoite proteins as shown in Table 1 and their expression pattern in the different mosquito stages. For example, proteins with multiple roles during sporozoite maturation (e.g. CS and TRAP) were identified in all stages (OOC, ODS and SGS) whereas proteins involved in hepatocyte traversal, such as SPECT1, SPECT2 (sporozoite microneme protein essential for cell traversal 1 and 2) and CelTOS (cell-traversal protein for ookinetes and sporozoites) were exclusively identified in mature SGS.

Bottom Line: The different sporozoite proteomes contain a large number of stage specific proteins whose annotation suggest an involvement in sporozoite maturation, motility, infection of the human host and associated metabolic adjustments.Analyses of proteins identified in the P. falciparum sporozoite proteomes by orthologous gene disruption in the rodent malaria parasite, P. berghei, revealed three previously uncharacterized Plasmodium proteins that appear to be essential for sporozoite development at distinct points of maturation in the mosquito.This study sheds light on the development and maturation of the malaria parasite in an Anopheles mosquito and also identifies proteins that may be essential for sporozoite infectivity to humans.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biology, NCMLS, Radboud University Nijmegen, Nijmegen, The Netherlands.

ABSTRACT
Plasmodium falciparum sporozoites that develop and mature inside an Anopheles mosquito initiate a malaria infection in humans. Here we report the first proteomic comparison of different parasite stages from the mosquito -- early and late oocysts containing midgut sporozoites, and the mature, infectious salivary gland sporozoites. Despite the morphological similarity between midgut and salivary gland sporozoites, their proteomes are markedly different, in agreement with their increase in hepatocyte infectivity. The different sporozoite proteomes contain a large number of stage specific proteins whose annotation suggest an involvement in sporozoite maturation, motility, infection of the human host and associated metabolic adjustments. Analyses of proteins identified in the P. falciparum sporozoite proteomes by orthologous gene disruption in the rodent malaria parasite, P. berghei, revealed three previously uncharacterized Plasmodium proteins that appear to be essential for sporozoite development at distinct points of maturation in the mosquito. This study sheds light on the development and maturation of the malaria parasite in an Anopheles mosquito and also identifies proteins that may be essential for sporozoite infectivity to humans.

Show MeSH
Related in: MedlinePlus