Giardiaintestinalis cystatin is a potent inhibitor of papain, parasite cysteine proteases and, to a lesser extent, human cathepsin B

FEBS Letters

article

Jingyi Liu¹  Staffan G. Svärd¹  Christian Klotz² 

[1] Department of Cell and Molecular Biology, Uppsala University;Department of Mycotic and Parasitic Agents and Mycobacteria (FG16), Robert Koch-Institute

关键词: cystatin;    cysteine protease inhibitor;    cysteine proteases;    Giardia intestinalis;    protozoa;   

DOI  :  10.1002/1873-3468.13433

来源: John Wiley & Sons Ltd.

【 摘 要 】

Cystatins are important regulators of papain-like cysteine proteases. In the protozoan parasite Giardia intestinalis, papain-like cysteine proteases play an essential role in the parasite’s biology and pathogenicity. Here, we characterized a cysteine protease inhibitor of G. intestinalis that belongs to type-Icystatins. The parasite cystatin is shown to be a strong inhibitor of papain (Ki ≈ 0.3 nM) and three parasite cysteine proteases (CP14019, CP16160 and CP16779, Ki ≈ 0.9–5.8 nM), but a weaker inhibitor of human cathepsin B (Ki ≈ 79.9 nM). The protein localizes mainly in the cytoplasm. Together, these data suggest that cystatin of G. intestinalis plays a role in the regulation of cysteine protease activities in the parasite and, possibly, in the interaction with the host.

【 授权许可】

Unknown