A Plasmodium falciparum Dipeptidyl Aminopeptidase I Participates in Vacuolar Hemoglobin Degradation

Klemba, Michael; Gluzman, Ilya Y.; Goldberg, Daniel E.

doi:10.1074/jbc.m408123200

Cited by 174 publications

(183 citation statements)

References 62 publications

(60 reference statements)

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“…TgCPC1 and TgCPC2 localize to dense granules (Fig. 8), similar to the localization of P. falciparum cathepsin C, which participates in the breakdown of hemoglobin (6). We showed that inhibition of TgCPC1 and TgCPC2 blocked the breakdown of a marker secreted protein, ␤-lactamase, in the PV (Fig.…”

Section: Discussionmentioning

confidence: 69%

“…Proteinases of Plasmodium appear to facilitate erythrocyte invasion and rupture by degrading cytoskeletal proteins and provide free amino acids by degrading host hemoglobin in food vacuoles. Specific inhibition of the Plasmodium cysteine proteinases causes accumulation of undegraded erythrocyte cytoplasm in the food vacuoles and inhibits multiplication (3)(4)(5)(6).…”

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confidence: 99%

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Cathepsin Cs Are Key for the Intracellular Survival of the Protozoan Parasite, Toxoplasma gondii

Que

Engel

Ferguson

et al. 2007

Journal of Biological Chemistry

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Cysteine proteases play key roles in apicomplexan invasion, organellar biogenesis, and intracellular survival. We have now characterized five genes encoding papain family cathepsins from Toxoplasma gondii, including three cathepsin Cs, one cathepsin B, and one cathepsin L. Unlike endopeptidases cathepsin B and L, T. gondii cathepsin Cs are exopeptidases and remove dipeptides from unblocked N-terminal substrates of proteins or peptides. TgCPC1 was the most highly expressed cathepsin mRNA in tachyzoites (by real-time PCR), but three cathepsins, TgCPC1, TgCPC2, and TgCPB, were undetectable in in vivo bradyzoites. The specific cathepsin C inhibitor, Gly-Phe-dimethylketone, selectively inhibited the TgCPCs activity, reducing parasite intracellular growth and proliferation. The targeted disruption of TgCPC1 does not affect the invasion and growth of tachyzoites as TgCPC2 is then up-regulated and may substitute for TgCPC1. TgCPC1 and TgCPC2 localize to constitutive secretory vesicles of tachyzoites, the dense granules. T. gondii cathepsin Cs are required for peptide degradation in the parasitophorous vacuole as the degradation of the marker protein, Escherichia coli ␤-lactamase, secreted into the parasitophorous vacuole of transgenic tachyzoites was completely inhibited by the cathepsin C inhibitor. Cathepsin C inhibitors also limited the in vivo infection of T. gondii in the chick embryo model of toxoplasmosis. Thus, cathepsin Cs are critical to T. gondii growth and differentiation, and their unique specificities could be exploited to develop novel chemotherapeutic agents.

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Section: Discussionmentioning

confidence: 69%

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confidence: 99%

Cathepsin Cs Are Key for the Intracellular Survival of the Protozoan Parasite, Toxoplasma gondii

Que

Engel

Ferguson

et al. 2007

Journal of Biological Chemistry

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“…*This Direct Submission article had a prearranged editor. To validate our approach in parasites, we used a potent and irreversible inhibitor of the parasite cysteine protease dipeptidyl aminopeptidase 1 (DPAP1) (23)(24)(25) as our "drug" species. Several factors drove the selection of the DPAP inhibitor ML4118S (24) (herein denoted ML) (Fig.…”

Section: Resultsmentioning

confidence: 99%

Ferrous iron-dependent drug delivery enables controlled and selective release of therapeutic agents in vivo

Deu¹,

Chen

Lauterwasser

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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The precise targeting of cytotoxic agents to specific cell types or cellular compartments is of significant interest in medicine, with particular relevance for infectious diseases and cancer. Here, we describe a method to exploit aberrant levels of mobile ferrous iron (Fe II ) for selective drug delivery in vivo. This approach makes use of a 1,2,4-trioxolane moiety, which serves as an Fe II -sensitive "trigger," making drug release contingent on Fe II -promoted trioxolane fragmentation. We demonstrate in vivo validation of this approach with the Plasmodium berghei model of murine malaria. Malaria parasites produce high concentrations of mobile ferrous iron as a consequence of their catabolism of host hemoglobin in the infected erythrocyte. Using activity-based probes, we successfully demonstrate the Fe II -dependent and parasite-selective delivery of a potent dipeptidyl aminopeptidase inhibitor. We find that delivery of the compound in its Fe II -targeted form leads to more sustained target inhibition with greatly reduced off-target inhibition of mammalian cathepsins. This selective drug delivery translates into improved efficacy and tolerability. These findings demonstrate the utility of a purely chemical means to achieve selective drug targeting in vivo. This approach may find useful application in parasitic infections and more broadly in any disease state characterized by aberrant production of reactive ferrous iron.iron-mediated delivery | targeted prodrugs | dipeptidyl peptidase | combination therapy

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“…Falcipain-1 (FP1) is much less similar in sequence (38% identity between the catalytic domains of FP1 and FP2), encoded by chromosome 14, and, as determined by recent gene disruption studies, not essential for erythrocytic parasites (16,17). Other putative P. falciparum family C1 proteases (15,18) are three dipeptidyl peptidases, one of which (dipeptidyl peptidase I) was recently characterized as an exopeptidase (19), and nine serine repeat antigens (SERAs), one of which (SERA-5, which has replacement of the catalytic Cys by Ser) was recently shown to have serine protease activity (20).…”

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confidence: 99%

The Plasmodium falciparum cysteine protease falcipain-2 captures its substrate, hemoglobin, via a unique motif

Pandey

Wang

Sijwali

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

122

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Falcipain-2 (FP2) is a papain family cysteine protease and important hemoglobinase of erythrocytic Plasmodium falciparum parasites. Inhibitors of FP2 block hemoglobin hydrolysis and parasite development, suggesting that this enzyme is a promising target for antimalarial chemotherapy. FP2 and related plasmodial cysteine proteases have an unusual 14-aa motif near the C terminus of the catalytic domain. Recent solution of the structure of FP2 showed this motif to form a ␤-hairpin that is distant from the enzyme active site and protrudes out from the protein. To evaluate the function of this motif, we compared the activity of the wild-type enzyme with that of a mutant lacking 10 aa of the motif ( ⌬10 FP2). ⌬10 FP2 had nearly identical activity to that of the wild-type enzyme against peptide substrates and the protein substrates casein and gelatin. However, ⌬10 FP2 demonstrated negligible activity against hemoglobin or globin. FP2 that was inhibited with trans-epoxysuccinyl-L-leucylamido-(4-guanidino)butane (FP2 E-64 ) formed a complex with hemoglobin, but ⌬10 FP2 E-64 did not, indicating that the motif mediates binding to hemoglobin independent of the active site. A peptide encoding the motif blocked hemoglobin hydrolysis, but not the hydrolysis of casein. Kinetics for the inhibition of ⌬10 FP2 were very similar to those for FP2 with peptidyl and protein inhibitors, but ⌬10 FP2 was poorly inhibited by the inhibitory prodomain of FP2. Our results indicate that FP2 utilizes an unusual motif for two specific functions, interaction with hemoglobin, its natural substrate, and interaction with the prodomain, its natural inhibitor.M alaria is one of the most important infectious diseases in the world. Plasmodium falciparum, the most virulent human malaria parasite, is believed to cause hundreds of millions of illnesses and over a million deaths each year (1). The control of malaria has been hindered by increasing resistance of malaria parasites to available drugs (2). New antimalarial drugs, ideally directed against new targets, are urgently needed (3). Among potential new targets for antimalarial therapy are proteases that hydrolyze hemoglobin. Intraerythrocytic malaria parasites break down hemoglobin in an acidic food vacuole to supply amino acids for parasite protein synthesis and to maintain osmotic stability (4, 5). Multiple proteases appear to participate in hemoglobin processing (6). Cysteine protease inhibitors block hemoglobin hydrolysis, indicating that cysteine proteases play a key role in this process (7). Falcipain-2 (FP2) and falcipain-3 (FP3) are papain-family cysteine proteases of erythrocytic stages of P. falciparum that localize to the food vacuole and readily hydrolyze hemoglobin (8, 9). Disruption of the FP2 gene led to the accumulation of undegraded hemoglobin in trophozoites, confirming a critical role for this enzyme in hemoglobin hydrolysis (10). Inhibition of FP2 and related proteases led to a block in parasite development (11, 12) and cured mice with murine malaria (13, 14), and efforts to develop...

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A Plasmodium falciparum Dipeptidyl Aminopeptidase I Participates in Vacuolar Hemoglobin Degradation

Cited by 174 publications

References 62 publications

Cathepsin Cs Are Key for the Intracellular Survival of the Protozoan Parasite, Toxoplasma gondii

Cathepsin Cs Are Key for the Intracellular Survival of the Protozoan Parasite, Toxoplasma gondii

Ferrous iron-dependent drug delivery enables controlled and selective release of therapeutic agents in vivo

The Plasmodium falciparum cysteine protease falcipain-2 captures its substrate, hemoglobin, via a unique motif

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