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A multidomain adhesion protein family expressed in Plasmodium falciparum is essential for transmission to the mosquito.

Pradel G, Hayton K, Aravind L, Iyer LM, Abrahamsen MS, Bonawitz A, Mejia C, Templeton TJ - J. Exp. Med. (2004)

Bottom Line: Three of these identified genes, named PfCCp1, PfCCp2, and PfCCp3, have multiple adhesive modules including a common Limulus coagulation factor C domain also found in two additional Plasmodium genes.PfCCp expression markedly decreased after formation of zygotes.Our results describe members of a conserved apicomplexan protein family expressed in sexual stage Plasmodium parasites that may represent candidates for subunits of a transmission-blocking vaccine.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10021, USA.

ABSTRACT
The recent sequencing of several apicomplexan genomes has provided the opportunity to characterize novel antigens essential for the parasite life cycle that might lead to the development of new diagnostic and therapeutic markers. Here we have screened the Plasmodium falciparum genome sequence for genes encoding extracellular multidomain putative adhesive proteins. Three of these identified genes, named PfCCp1, PfCCp2, and PfCCp3, have multiple adhesive modules including a common Limulus coagulation factor C domain also found in two additional Plasmodium genes. Orthologues were identified in the Cryptosporidium parvum genome sequence, indicating an evolutionary conserved function. Transcript and protein expression analysis shows sexual stage-specific expression of PfCCp1, PfCCp2, and PfCCp3, and cellular localization studies revealed plasma membrane-associated expression in mature gametocytes. During gametogenesis, PfCCps are released and localize surrounding complexes of newly emerged microgametes and macrogametes. PfCCp expression markedly decreased after formation of zygotes. To begin to address PfCCp function, the PfCCp2 and PfCCp3 gene loci were disrupted by homologous recombination, resulting in parasites capable of forming oocyst sporozoites but blocked in the salivary gland transition. Our results describe members of a conserved apicomplexan protein family expressed in sexual stage Plasmodium parasites that may represent candidates for subunits of a transmission-blocking vaccine.

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Phylogenetic trees showing affinity of apicomplexan versions to bacterial discoidin (A) and animal NEC (B) domains. Principal nodes supported by bootstrap values of >65% are shown with a filled green circle. Clades containing apicomplexan sequences are colored blue and apicomplexan sequences are boxed. Genes are designated by their gene names and the abbreviated source species names are as follows: Art, Arthrobacter spp.; At, Arabidopsis thaliana; Bh, Bacillus halodurans; Bsp, Bacillus spp. D-2; Ce, Caenorrhabditis elegans; Clpe, Clostridium perfringens; Cp, Cryptosporidium parvum; Dd, Dictyostelium discoidium; Dm, Drosophila melanogaster; Hs, Homo sapiens; Hyro, Hypomyces rosellus; Lal, Lactococcus lactis; Mivi, Micromonospora viridifaciens; Pf, Plasmodium falciparum; Scoe, Streptomyces coelicolor; Xf, Xylella fastidiosa; Yp, Yersinia pestis.
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fig3: Phylogenetic trees showing affinity of apicomplexan versions to bacterial discoidin (A) and animal NEC (B) domains. Principal nodes supported by bootstrap values of >65% are shown with a filled green circle. Clades containing apicomplexan sequences are colored blue and apicomplexan sequences are boxed. Genes are designated by their gene names and the abbreviated source species names are as follows: Art, Arthrobacter spp.; At, Arabidopsis thaliana; Bh, Bacillus halodurans; Bsp, Bacillus spp. D-2; Ce, Caenorrhabditis elegans; Clpe, Clostridium perfringens; Cp, Cryptosporidium parvum; Dd, Dictyostelium discoidium; Dm, Drosophila melanogaster; Hs, Homo sapiens; Hyro, Hypomyces rosellus; Lal, Lactococcus lactis; Mivi, Micromonospora viridifaciens; Pf, Plasmodium falciparum; Scoe, Streptomyces coelicolor; Xf, Xylella fastidiosa; Yp, Yersinia pestis.

Mentions: PfCCp1 and PfCCp2 have similar architectures and are paralogs arising via relatively recent gene duplication after domain accretion. C. parvum also has paralogs, CpCCp1 and CpCCp2, and thus the gene duplication event likely occurred before the divergence of the apicomplexan genera. Within PfCCp1 and PfCCp2, we identified three predicted polysaccharide-binding domains, namely ricin, discoidin, and levanase-type lectin domains (26, 27). COOH terminal to these modules are two copies of an apicomplexan-specific cysteine-rich module (herein termed ApicA) that has not been identified in any other gene. Between the discoidin and levanase lectin domains there are two distinct cysteine-rich modules, the described animal- and fungal-specific LCCL domain (28), and a novel module, termed NEC, which appears in a wide range of animal proteins such as neurexins (29), fibrillar collagen α globular domain (30) from vertebrates and sponges, and the fibrinogen family of proteins (31). The NEC domain has not been identified previously as a distinct module because in all the animal instances it occurs in combination with other cysteine-rich segments. This has resulted in it being considered a portion of several other distinct modules such as the fibrinogen globular domain (31, 32) or the fibrillar collagen α COOH-terminal globular domain (30). We term this module the NEC domain after neurexins (29) and collagens, the two ancient animal surface proteins in which they are represented. This is the first instance in which the NEC domain occurs in a stand alone form and is consistent with it forming a distinct NH2-terminal folding α-β3 unit stabilized by a cysteine bridge in the fibrinogen crystal structure (Fig. 2). The structure of this domain reveals a distinct cleft that is likely to function as a binding pocket (32). Several animal proteins functioning as lectins contain the NEC domain, such as ficolin and intelectin (33, 34), suggesting that it probably represents a fourth sugar-binding domain in the PfCCp proteins. Phylogenetic analysis suggests that the levanase lectin and discoidin domains group closer to the bacterial forms as opposed to those from other organisms (Fig. 3 A), whereas the NEC domain groups with animal affinity (Fig. 3 B). Thus, the extracellular adhesion modules can be attributed to multiple distinct heritages, those originally derived in bacteria or animals and laterally transferred to Apicomplexa, and those “invented” within the lineage leading to the Apicomplexa.


A multidomain adhesion protein family expressed in Plasmodium falciparum is essential for transmission to the mosquito.

Pradel G, Hayton K, Aravind L, Iyer LM, Abrahamsen MS, Bonawitz A, Mejia C, Templeton TJ - J. Exp. Med. (2004)

Phylogenetic trees showing affinity of apicomplexan versions to bacterial discoidin (A) and animal NEC (B) domains. Principal nodes supported by bootstrap values of >65% are shown with a filled green circle. Clades containing apicomplexan sequences are colored blue and apicomplexan sequences are boxed. Genes are designated by their gene names and the abbreviated source species names are as follows: Art, Arthrobacter spp.; At, Arabidopsis thaliana; Bh, Bacillus halodurans; Bsp, Bacillus spp. D-2; Ce, Caenorrhabditis elegans; Clpe, Clostridium perfringens; Cp, Cryptosporidium parvum; Dd, Dictyostelium discoidium; Dm, Drosophila melanogaster; Hs, Homo sapiens; Hyro, Hypomyces rosellus; Lal, Lactococcus lactis; Mivi, Micromonospora viridifaciens; Pf, Plasmodium falciparum; Scoe, Streptomyces coelicolor; Xf, Xylella fastidiosa; Yp, Yersinia pestis.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2211786&req=5

fig3: Phylogenetic trees showing affinity of apicomplexan versions to bacterial discoidin (A) and animal NEC (B) domains. Principal nodes supported by bootstrap values of >65% are shown with a filled green circle. Clades containing apicomplexan sequences are colored blue and apicomplexan sequences are boxed. Genes are designated by their gene names and the abbreviated source species names are as follows: Art, Arthrobacter spp.; At, Arabidopsis thaliana; Bh, Bacillus halodurans; Bsp, Bacillus spp. D-2; Ce, Caenorrhabditis elegans; Clpe, Clostridium perfringens; Cp, Cryptosporidium parvum; Dd, Dictyostelium discoidium; Dm, Drosophila melanogaster; Hs, Homo sapiens; Hyro, Hypomyces rosellus; Lal, Lactococcus lactis; Mivi, Micromonospora viridifaciens; Pf, Plasmodium falciparum; Scoe, Streptomyces coelicolor; Xf, Xylella fastidiosa; Yp, Yersinia pestis.
Mentions: PfCCp1 and PfCCp2 have similar architectures and are paralogs arising via relatively recent gene duplication after domain accretion. C. parvum also has paralogs, CpCCp1 and CpCCp2, and thus the gene duplication event likely occurred before the divergence of the apicomplexan genera. Within PfCCp1 and PfCCp2, we identified three predicted polysaccharide-binding domains, namely ricin, discoidin, and levanase-type lectin domains (26, 27). COOH terminal to these modules are two copies of an apicomplexan-specific cysteine-rich module (herein termed ApicA) that has not been identified in any other gene. Between the discoidin and levanase lectin domains there are two distinct cysteine-rich modules, the described animal- and fungal-specific LCCL domain (28), and a novel module, termed NEC, which appears in a wide range of animal proteins such as neurexins (29), fibrillar collagen α globular domain (30) from vertebrates and sponges, and the fibrinogen family of proteins (31). The NEC domain has not been identified previously as a distinct module because in all the animal instances it occurs in combination with other cysteine-rich segments. This has resulted in it being considered a portion of several other distinct modules such as the fibrinogen globular domain (31, 32) or the fibrillar collagen α COOH-terminal globular domain (30). We term this module the NEC domain after neurexins (29) and collagens, the two ancient animal surface proteins in which they are represented. This is the first instance in which the NEC domain occurs in a stand alone form and is consistent with it forming a distinct NH2-terminal folding α-β3 unit stabilized by a cysteine bridge in the fibrinogen crystal structure (Fig. 2). The structure of this domain reveals a distinct cleft that is likely to function as a binding pocket (32). Several animal proteins functioning as lectins contain the NEC domain, such as ficolin and intelectin (33, 34), suggesting that it probably represents a fourth sugar-binding domain in the PfCCp proteins. Phylogenetic analysis suggests that the levanase lectin and discoidin domains group closer to the bacterial forms as opposed to those from other organisms (Fig. 3 A), whereas the NEC domain groups with animal affinity (Fig. 3 B). Thus, the extracellular adhesion modules can be attributed to multiple distinct heritages, those originally derived in bacteria or animals and laterally transferred to Apicomplexa, and those “invented” within the lineage leading to the Apicomplexa.

Bottom Line: Three of these identified genes, named PfCCp1, PfCCp2, and PfCCp3, have multiple adhesive modules including a common Limulus coagulation factor C domain also found in two additional Plasmodium genes.PfCCp expression markedly decreased after formation of zygotes.Our results describe members of a conserved apicomplexan protein family expressed in sexual stage Plasmodium parasites that may represent candidates for subunits of a transmission-blocking vaccine.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10021, USA.

ABSTRACT
The recent sequencing of several apicomplexan genomes has provided the opportunity to characterize novel antigens essential for the parasite life cycle that might lead to the development of new diagnostic and therapeutic markers. Here we have screened the Plasmodium falciparum genome sequence for genes encoding extracellular multidomain putative adhesive proteins. Three of these identified genes, named PfCCp1, PfCCp2, and PfCCp3, have multiple adhesive modules including a common Limulus coagulation factor C domain also found in two additional Plasmodium genes. Orthologues were identified in the Cryptosporidium parvum genome sequence, indicating an evolutionary conserved function. Transcript and protein expression analysis shows sexual stage-specific expression of PfCCp1, PfCCp2, and PfCCp3, and cellular localization studies revealed plasma membrane-associated expression in mature gametocytes. During gametogenesis, PfCCps are released and localize surrounding complexes of newly emerged microgametes and macrogametes. PfCCp expression markedly decreased after formation of zygotes. To begin to address PfCCp function, the PfCCp2 and PfCCp3 gene loci were disrupted by homologous recombination, resulting in parasites capable of forming oocyst sporozoites but blocked in the salivary gland transition. Our results describe members of a conserved apicomplexan protein family expressed in sexual stage Plasmodium parasites that may represent candidates for subunits of a transmission-blocking vaccine.

Show MeSH
Related in: MedlinePlus