Limits...
Profiling of proteolytic enzymes in the gut of the tick Ixodes ricinus reveals an evolutionarily conserved network of aspartic and cysteine peptidases.

Sojka D, Franta Z, Horn M, Hajdusek O, Caffrey CR, Mares M, Kopácek P - Parasit Vectors (2008)

Bottom Line: Overall, our results demonstrate the presence of a network of cysteine and aspartic peptidases that conceivably operates to digest host blood proteins in a concerted manner.Significantly, the peptidase components of this digestive network are orthologous to those described in other parasites, including nematodes and flatworms.Accordingly, the present data and those available for other tick species support the notion of an evolutionary conservation of a cysteine/aspartic peptidase system for digestion that includes ticks, but differs from that of insects relying on serine peptidases.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Parasitology, Biology Centre, Academy of Sciences of the Czech Republic, Ceské Budejovice, CZ-370 05, The Czech Republic. dsojka@seznam.cz.

ABSTRACT

Background: Ticks are vectors for a variety of viral, bacterial and parasitic diseases in human and domestic animals. To survive and reproduce ticks feed on host blood, yet our understanding of the intestinal proteolytic machinery used to derive absorbable nutrients from the blood meal is poor. Intestinal digestive processes are limiting factors for pathogen transmission since the tick gut presents the primary site of infection. Moreover, digestive enzymes may find practical application as anti-tick vaccine targets.

Results: Using the hard tick, Ixodes ricinus, we performed a functional activity scan of the peptidase complement in gut tissue extracts that demonstrated the presence of five types of peptidases of the cysteine and aspartic classes. We followed up with genetic screens of gut-derived cDNA to identify and clone genes encoding the cysteine peptidases cathepsins B, L and C, an asparaginyl endopeptidase (legumain), and the aspartic peptidase, cathepsin D. By RT-PCR, expression of asparaginyl endopeptidase and cathepsins B and D was restricted to gut tissue and to those developmental stages feeding on blood.

Conclusion: Overall, our results demonstrate the presence of a network of cysteine and aspartic peptidases that conceivably operates to digest host blood proteins in a concerted manner. Significantly, the peptidase components of this digestive network are orthologous to those described in other parasites, including nematodes and flatworms. Accordingly, the present data and those available for other tick species support the notion of an evolutionary conservation of a cysteine/aspartic peptidase system for digestion that includes ticks, but differs from that of insects relying on serine peptidases.

No MeSH data available.


Related in: MedlinePlus

Nucleotide and deduced amino acid sequence of Ixodes ricinus cathepsin D (IrCD). The depictions of PCR primers, putative 21 AA signal peptide, two potential N-glycosylation sites and active site residues D79, Y111, D270 are as in Fig 4.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2289814&req=5

Figure 7: Nucleotide and deduced amino acid sequence of Ixodes ricinus cathepsin D (IrCD). The depictions of PCR primers, putative 21 AA signal peptide, two potential N-glycosylation sites and active site residues D79, Y111, D270 are as in Fig 4.

Mentions: A cathepsin-D-like aspartic peptidase precursor of 322 amino acid residues (Fig. 7) is encoded by a 1304 bp long cDNA sequence [GenBank:EF428204]. The predicted signal peptide counts for 21 AA residues. The active site contains two catalytic aspartic acid residues D79 and D270 within the conserved D-T-G motifs and Y111. Molecular weight of the proenzyme without the signal peptide is 39.451 Da and the theoretical isoelectric point is 4.75. There are only two possible N-glycosylation sites in the IrCD proenzyme.


Profiling of proteolytic enzymes in the gut of the tick Ixodes ricinus reveals an evolutionarily conserved network of aspartic and cysteine peptidases.

Sojka D, Franta Z, Horn M, Hajdusek O, Caffrey CR, Mares M, Kopácek P - Parasit Vectors (2008)

Nucleotide and deduced amino acid sequence of Ixodes ricinus cathepsin D (IrCD). The depictions of PCR primers, putative 21 AA signal peptide, two potential N-glycosylation sites and active site residues D79, Y111, D270 are as in Fig 4.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2289814&req=5

Figure 7: Nucleotide and deduced amino acid sequence of Ixodes ricinus cathepsin D (IrCD). The depictions of PCR primers, putative 21 AA signal peptide, two potential N-glycosylation sites and active site residues D79, Y111, D270 are as in Fig 4.
Mentions: A cathepsin-D-like aspartic peptidase precursor of 322 amino acid residues (Fig. 7) is encoded by a 1304 bp long cDNA sequence [GenBank:EF428204]. The predicted signal peptide counts for 21 AA residues. The active site contains two catalytic aspartic acid residues D79 and D270 within the conserved D-T-G motifs and Y111. Molecular weight of the proenzyme without the signal peptide is 39.451 Da and the theoretical isoelectric point is 4.75. There are only two possible N-glycosylation sites in the IrCD proenzyme.

Bottom Line: Overall, our results demonstrate the presence of a network of cysteine and aspartic peptidases that conceivably operates to digest host blood proteins in a concerted manner.Significantly, the peptidase components of this digestive network are orthologous to those described in other parasites, including nematodes and flatworms.Accordingly, the present data and those available for other tick species support the notion of an evolutionary conservation of a cysteine/aspartic peptidase system for digestion that includes ticks, but differs from that of insects relying on serine peptidases.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Parasitology, Biology Centre, Academy of Sciences of the Czech Republic, Ceské Budejovice, CZ-370 05, The Czech Republic. dsojka@seznam.cz.

ABSTRACT

Background: Ticks are vectors for a variety of viral, bacterial and parasitic diseases in human and domestic animals. To survive and reproduce ticks feed on host blood, yet our understanding of the intestinal proteolytic machinery used to derive absorbable nutrients from the blood meal is poor. Intestinal digestive processes are limiting factors for pathogen transmission since the tick gut presents the primary site of infection. Moreover, digestive enzymes may find practical application as anti-tick vaccine targets.

Results: Using the hard tick, Ixodes ricinus, we performed a functional activity scan of the peptidase complement in gut tissue extracts that demonstrated the presence of five types of peptidases of the cysteine and aspartic classes. We followed up with genetic screens of gut-derived cDNA to identify and clone genes encoding the cysteine peptidases cathepsins B, L and C, an asparaginyl endopeptidase (legumain), and the aspartic peptidase, cathepsin D. By RT-PCR, expression of asparaginyl endopeptidase and cathepsins B and D was restricted to gut tissue and to those developmental stages feeding on blood.

Conclusion: Overall, our results demonstrate the presence of a network of cysteine and aspartic peptidases that conceivably operates to digest host blood proteins in a concerted manner. Significantly, the peptidase components of this digestive network are orthologous to those described in other parasites, including nematodes and flatworms. Accordingly, the present data and those available for other tick species support the notion of an evolutionary conservation of a cysteine/aspartic peptidase system for digestion that includes ticks, but differs from that of insects relying on serine peptidases.

No MeSH data available.


Related in: MedlinePlus