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Characterization of major surface protease (MSP) in axenic cultured amastigotes of Leishmania chagasi
Author(s) -
Hsiao ChiaHung Christine,
Yao Chaoqun,
Donelson John E,
Wilson Mary E
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a650-c
Subject(s) - amastigote , leishmania , biology , intracellular , axenic , extracellular , microbiology and biotechnology , leishmania chagasi , protease , biochemistry , leishmaniasis , parasite hosting , visceral leishmaniasis , enzyme , immunology , genetics , world wide web , computer science , bacteria
MSP is a virulence factor of Leishmania spp. protozoa, which cause the human disease, leishmaniasis. MSP is a surface metalloprotease encoded by three distinct gene classes in Leishmania chagasi (MSPL, MSPS and MSPC) . Although MSP was discovered and characterized in the extracellular promastigote stage, there is evidence that it facilitates intracellular survival of the amastigote stage. We compared MSP protein isoforms of axenic L. chagasi amastigotes with those of promastigotes. Immuno‐electron microscopy showed 2/3 of total promastigote MSP is localized on the surface and 1/3 is intracellular. In contrast, most amastigote MSP is intracellular and localized at the flagellar pocket, the major site of endocytosis/exocytosis in leishmania. Alkaline carbonate treatment and high‐salt washing indicated that the majority of amastigote MSP is cytosolic with a minor luminal component, whereas most promastigote MSP is anchored in the surface membrane. Protease gels showed that both forms of the parasites synthesize metalloproteases, active at pH7.9 and 5.5. We conclude that intracellular L. chagasi amastigotes express multiple MSP isoforms similar to promastigotes, but amastigote MSPs differ from promastigote MSPs biochemically, and localize differently in the parasite cell. These observations suggest the abundant MSP protease plays different roles in the extracellular versus intracellular environment. [Support: NIH, MREP]