The role of aminopeptidases in haemoglobin degradation in Plasmodium falciparum-infected erythrocytes

Gavigan, C. S.; Dalton, John P.; Bell, Angus

doi:10.1016/s0166-6851(01)00327-9

Cited by 104 publications

(98 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The specific role of LAPs in plant and animal tissues is not known but their expression in different tissues is consistent with their role in a variety of processes such as the maturation of proteins, the terminal degradation of proteins and the metabolism of secreted regulatory molecules (Strater and Lipscomb, 1998). Since they are exopeptidases, they must function in degrading either biologically active small peptides, such as hormones, or large polypeptides in concert with endopeptidases (Strater and Lipscomb, 1998;Gavigan et al, 2001). In this context, it is of interest to note that cathepsin L1 (Dalton et al, 1996;Brady et al, 1999a,b) and cathepsin B2 (Caffrey et al, 2002) endoproteases have also been localised to the tegument and hence it is plausible that a multi-enzymatic degradation process, similar to that described for hemoglobin digestion in the gut, also occurs in this tissue.…”

Section: Discussionmentioning

confidence: 99%

“…The assays were carried out by incubating samples in a reaction mix of 10 mM fluorogenic peptidyl substrate, 0.5 mM MgCl 2 and 0.1 M Tris -HCl (pH 8.5) in a final volume of 1 ml at 37 8C for 30 min as described before (Gavigan et al, 2001). A standard curve was prepared using 0 -10 mM NHMec and enzyme units presented nmol NHMec released/min/ml.…”

Section: Fluorogenic Substrate Assay and Fluorographic Gel Analysis Fmentioning

confidence: 99%

See 1 more Smart Citation

Leucine aminopeptidase of the human blood flukes, Schistosoma mansoni and Schistosoma japonicum

McCarthy

Stack

Donnelly

et al. 2004

International Journal for Parasitology

View full text Add to dashboard Cite

An array of schistosome endoproteases involved in the digestion of host hemoglobin to absorbable peptides has been described, but the exoprotease responsible for catabolising these peptides to amino acids has yet to be identified. By searching the public databases we found that Schistosoma mansoni and Schistosoma japonicum express a gene encoding a member of the M17 family of leucine aminopeptidases (LAPs). A functional recombinant S. mansoni LAP produced in insect cells shared biochemical properties, including pH optimum for activity, substrate specificity and reliance on metal cations for activity, with the major aminopeptidase activity in soluble extracts of adult worms. The pH range in which the enzyme functions and the lack of a signal peptide indicate that the enzyme functions intracellularly. Immunolocalisation studies showed that the S. mansoni LAP is synthesised in the gastrodermal cells surrounding the gut lumen. Accordingly, we propose that peptides generated in the lumen of the schistosome gut are absorbed into the gastrodermal cells and are cleaved by LAP to free amino acids before being distributed to the internal tissues of the parasite. Since LAP was also localised to the surface tegument it may play an additional role in surface membrane re-modelling. q

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Fluorogenic Substrate Assay and Fluorographic Gel Analysis Fmentioning

confidence: 99%

Leucine aminopeptidase of the human blood flukes, Schistosoma mansoni and Schistosoma japonicum

McCarthy

Stack

Donnelly

et al. 2004

International Journal for Parasitology

View full text Add to dashboard Cite

show abstract

“…It is unlikely that the digestive cascade consists of just these three enzymes; the related human hookworm, N. americanus, expresses at least two hemogobinolytic aspartic proteases in the intestine (19,20), and unpublished scans of the N. americanus expressed sequence tag data set revealed a family of at least five distinct cysteine proteases from adult parasites. 3 Moreover, we have identified an aminopeptidase from A. caninum 4 that might be involved in Hb catalysis, given that similar aminopeptidases from P. falciparum trophozoites (46) and S. mansoni gastrodermal cells (47) are thought to be involved in the downstream proteolytic degradation of Hb. Other exopeptidases including carboxypeptidases are also likely to be involved in the release of free amino acids in hookworms.…”

Section: Ac-apr-1 Ac-cp-2 and Ac-mep-1 Degrade Hb In A Semiorderedmentioning

confidence: 99%

A Multi-enzyme Cascade of Hemoglobin Proteolysis in the Intestine of Blood-feeding Hookworms

Williamson¹,

Lecchi

Turk

et al. 2004

Journal of Biological Chemistry

157

115

View full text Add to dashboard Cite

Blood-feeding pathogens digest hemoglobin (Hb) as a source of nutrition, but little is known about this process in multicellular parasites. The intestinal brush border membrane of the canine hookworm, Ancylostoma caninum, contains aspartic proteases (APR-1), cysteine proteases (CP-2), and metalloproteases (MEP-1), the first of which is known to digest Hb. We now show that Hb is degraded by a multi-enzyme, synergistic cascade of proteolysis. Recombinant APR-1 and CP-2, but not MEP-1, digested native Hb and denatured globin. MEP-1, however, did cleave globin fragments that had undergone prior digestion by APR-1 and CP-2. Proteolytic cleavage sites within the Hb ␣ and ␤ chains were determined for the three enzymes, identifying a total of 131 cleavage sites. By scanning synthetic combinatorial peptide libraries with each enzyme, we compared the preferred residues cleaved in the libraries with the known cleavage sites within Hb. The semi-ordered pathway of Hb digestion described here is surprisingly similar to that used by Plasmodium to digest Hb and provides a potential mechanism by which these hemoglobinases are efficacious vaccines in animal models of hookworm infection.

show abstract

“…A model for hemoglobin degradation was proposed that envisioned export of hemoglobin-derived oligopeptides from the food vacuole to the cytoplasm for terminal degradation by neutral aminopeptidases. This model has been supported by the identification of cytosolic aminopeptidase activity in P. falciparum that can partially degrade hemoglobin peptides (18) and the description of a cytosolic zinc aminopeptidase with broad substrate specificity that is enriched at the cytosolic face of the food vacuole (19). However, direct evidence for the transport of oligopeptides out of the food vacuole has not yet been reported.…”

mentioning

confidence: 98%

A Plasmodium falciparum Dipeptidyl Aminopeptidase I Participates in Vacuolar Hemoglobin Degradation

Klemba

Gluzman

Goldberg

2004

Journal of Biological Chemistry

174

View full text Add to dashboard Cite

Intraerythrocytic growth of the human malaria parasite Plasmodium falciparum requires the catabolism of large amounts of host cell hemoglobin. Endoproteolytic digestion of hemoglobin to short oligopeptides occurs in an acidic organelle called the food vacuole. How amino acids are generated from these peptides is not well understood. To gain insight into this process, we have studied a plasmodial ortholog of the lysosomal exopeptidase cathepsin C. The plasmodial enzyme dipeptidyl aminopeptidase 1 (DPAP1) was enriched from parasite extract by two different approaches and was shown to possess hydrolytic activity against fluorogenic dipeptide substrates. To localize DPAP1 we created a transgenic parasite line expressing a chromosomally encoded DPAP1-green fluorescent protein fusion. Green fluorescent protein fluorescence was observed in the food vacuole of live transgenic parasites, and anti-DPAP1 antibody labeled the food vacuole in parasite cryosections. Together these data implicate DPAP1 in the generation of dipeptides from hemoglobin-derived oligopeptides. To assess the significance of DPAP1, we attempted to ablate DPAP1 activity from blood stage parasites by truncating the chromosomal DPAP1-coding sequence. The inability to disrupt the coding sequence indicates that DPAP1 is important for asexual proliferation. The proenzyme form of DPAP1 was found to accumulate in the parasitophorous vacuole of mature parasites. This observation suggests a trafficking route for DPAP1 through the parasitophorous vacuole to the food vacuole.

show abstract

The role of aminopeptidases in haemoglobin degradation in Plasmodium falciparum-infected erythrocytes

Cited by 104 publications

References 29 publications

Leucine aminopeptidase of the human blood flukes, Schistosoma mansoni and Schistosoma japonicum

Leucine aminopeptidase of the human blood flukes, Schistosoma mansoni and Schistosoma japonicum

A Multi-enzyme Cascade of Hemoglobin Proteolysis in the Intestine of Blood-feeding Hookworms

A Plasmodium falciparum Dipeptidyl Aminopeptidase I Participates in Vacuolar Hemoglobin Degradation

Contact Info

Product

Resources

About