The Leishmania donovani histidine acid ecto-phosphatase LdMAcP: insight into its structure and function.

Amalia Papadaki,Haralabia Boleti,Despina Smirlis,Thomais Papamarcaki,Anastasia S Politou,Maria P Kotini,Konstadina Kourou

doi:10.1042/bj20141371

Amalia Papadaki, Haralabia Boleti + Show 5 more

Open Access

https://doi.org/10.1042/bj20141371

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Abstract

Acid ecto-phosphatase activity has been implicated in Leishmania donovani promastigote virulence. In the present study, we report data contributing to the molecular/structural and functional characterization of the L. donovani LdMAcP (L. donovani membrane acid phosphatase), member of the histidine acid phosphatase (HAcP) family. LdMAcP is membrane-anchored and shares high sequence identity with the major secreted L. donovani acid phosphatases (LdSAcPs). Sequence comparison of the LdMAcP orthologues in Leishmania sp. revealed strain polymorphism and species specificity for the L. donovani complex, responsible for visceral leishmaniasis (Khala azar), proposing thus a potential value of LdMAcP as an epidemiological or diagnostic tool. The extracellular orientation of the LdMAcP catalytic domain was confirmed in L. donovani promastigotes, wild-type (wt) and transgenic overexpressing a recombinant LdMAcP–mRFP1 (monomeric RFP1) chimera, as well as in transiently transfected mammalian cells expressing rLdMAcP–His. For the first time it is demonstrated in the present study that LdMAcP confers tartrate resistant acid ecto-phosphatase activity in live L. donovani promastigotes. The latter confirmed the long sought molecular identity of at least one enzyme contributing to this activity. Interestingly, the L. donovani rLdMAcP–mRFP1 promastigotes generated in this study, showed significantly higher infectivity and virulence indexes than control parasites in the infection of J774 mouse macrophages highlighting thereby a role for LdMAcP in the parasite's virulence.

Highlights

Species of the parasitic protozoan genus Leishmania are the causative agents of a wide variety of human cutaneous and visceral diseases known as leishmaniases [1]
The experimental evidence presented in the present study shows that Leishmania donovani membrane acid phosphatase (LdMAcP) is specific for the L. donovani complex and is one, if not the only, enzyme contributing to the L. donovani acid-ecto-phosphatase activity
Identification of the LdBPK_366740.1 gene locus on a circular episome, implicated in the gene dosage effect associated with drug resistance, suggests that expression of this gene might be regulated by the parasite by several environment dependent mechanisms [46]

Summary

Introduction

Species of the parasitic protozoan genus Leishmania are the causative agents of a wide variety of human cutaneous and visceral diseases known as leishmaniases [1]. Membrane bound ecto-enzymes with their active sites facing the extracellular medium, are anticipated to play a critical role in the survival and maintenance of the parasite within the infected host. One class of such enzymes are ecto-phosphatases that hydrolyse extracellular phosphorylated substrates and release free inorganic phosphate (Pi). Their activities can be measured in live cells.

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