A cathepsin L-like cysteine protease is conserved among Babesia equi isolates

Mouse cytotoxic T-lymphocyte antigen-2α (CTLA-2α), Drosophila CTLA-2-like protein (crammer), and Bombyx cysteine protease inhibitor (BCPI) belong to a novel family of cysteine protease inhibitors (I29). Their inhibitory mechanisms were studied comparatively. CTLA-2α contains a cysteine residue (C75), which is essential for its inhibitory potency. The CTLA-2α monomer was converted to a disulfide-bonded dimer in vitro and in vivo. The dimer was fully inhibitory, but the monomer, which possessed a free thiol residue, was not. A disulfide-bonded CTLA-2α/cathepsin L complex was isolated, and a cathepsin L subunit with a molecular weight of 24,000 was identified as the interactive enzyme protein. Crammer also contains a cysteine residue (C72). Both dimeric and monomeric forms of crammer were inhibitory. A crammer mutant with Cys72 to alanine (C72A) was fully inhibitory, while the replacement of Gly73 with alanine (G73A) caused a significant loss in inhibitory potency, which suggests a different inhibition mechanism from CTLA-2α. BCPI does not contain cysteine residue. C-terminal region (L77-R80) of BCPI was essential for its inhibitory potency. CTLA-2α was inhibitory in the acidic pH condition but stabilized cathepsin L under neutral pH conditions. The different inhibition mechanisms and functional considerations of these inhibitors are discussed.

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Identification and characteristics of a cathepsin L-like cysteine protease from Clonorchis sinensis

Parasitology Research ◽

10.1007/s00436-019-06223-y ◽

2019 ◽

Vol 118 (3) ◽

pp. 829-835 ◽

Cited By ~ 2

Author(s):

Changling Ma ◽

Kai Liang ◽

Lili Tang ◽

Shanshan He ◽

Xiaoquan Liu ◽

...

Keyword(s):

Cysteine Protease ◽

Cathepsin L ◽

Clonorchis Sinensis

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Cathepsin L—a novel cysteine protease from Haemaphysalis flava Neumann, 1897

Parasitology Research ◽

10.1007/s00436-019-06271-4 ◽

2019 ◽

Vol 118 (5) ◽

pp. 1581-1592 ◽

Cited By ~ 2

Author(s):

Yali Sun ◽

Lan He ◽

Long Yu ◽

Jiaying Guo ◽

Zheng Nie ◽

...

Keyword(s):

Cysteine Protease ◽

Cathepsin L ◽

Haemaphysalis Flava

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Presence of Anti-cystatin C–positive Dendritic Cells or Macrophages and Localization of Cysteine Proteases in the Apical Bud of the Enamel Organ in the Rat Incisor

Journal of Histochemistry & Cytochemistry ◽

10.1369/jhc.4a6533.2005 ◽

2005 ◽

Vol 53 (5) ◽

pp. 643-651 ◽

Cited By ~ 1

Author(s):

Sumio Nishikawa

Keyword(s):

Dendritic Cells ◽

Cystatin C ◽

Cysteine Protease ◽

Cathepsin L ◽

Cysteine Proteases ◽

Cysteine Protease Inhibitor ◽

Enamel Organ ◽

Apical Bud ◽

Apical Buds ◽

Proliferation And Differentiation

Cystatin C, a cysteine protease inhibitor, was examined in the apical buds of rat incisors by immunohistochemistry, because in transition and maturation zones most of the dendritic cells in the papillary layer are anti-cystatin C–positive. Anti-cystatin C–labeled cells were sparse and localized to the proliferation and differentiation zones, constituting the apical bud of 5-week-old rat incisors. These cells were considered macrophages or dendritic cells, based on their reactivity with OX6 and ED1, as well as their ultrastructure. Basement membrane at the periphery of apical bud was also labeled by anti-cystatin C antibody. The apical buds included a few apoptotic fragments and weak reactivity with antibody to cathepsin L, a cysteine protease. Reactivity to anti-cystatin C and anti-cathepsin ∗∗∗L antibodies was also detected in the apical bud of newborn rat incisors. These results suggest that the cystatin C–positive macrophages or dendritic cells are involved in normal incisor formation. They may be related to the clearance of apoptotic cells or protection from putative cysteine protease activity.

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Molecular cloning and characterization of a cathepsin L-like cysteine protease of Angiostrongylus cantonensis

International Journal of Biological Macromolecules ◽

10.1016/j.ijbiomac.2019.10.243 ◽

2020 ◽

Vol 153 ◽

pp. 1136-1146

Author(s):

Huifang Bai ◽

Yizhen Cao ◽

Yunqiu Chen ◽

Lingmin Zhang ◽

Chunyun Wu ◽

...

Keyword(s):

Molecular Cloning ◽

Cysteine Protease ◽

Cathepsin L ◽

Angiostrongylus Cantonensis

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Cryptopain-1, a cysteine protease of Cryptosporidium parvum, does not require the pro-domain for folding

Parasitology ◽

10.1017/s0031182008005350 ◽

2008 ◽

Vol 136 (2) ◽

pp. 149-157 ◽

Cited By ~ 14

Author(s):

B.-K. NA ◽

J.-M. KANG ◽

H.-I. CHEUN ◽

S.-H. CHO ◽

S.-U. MOON ◽

...

Keyword(s):

Cryptosporidium Parvum ◽

Cysteine Protease ◽

Transmembrane Domain ◽

Cathepsin L ◽

Active Form ◽

Protozoan Parasite ◽

Biochemical Properties ◽

Peptide Sequence ◽

Signal Peptide Sequence ◽

Mature Domain

SUMMARYCryptosporidium parvum is an intracellular protozoan parasite that causes cryptosporidiosis in mammals including humans. In the current study, the gene encoding the cysteine protease of C. parvum (cryptopain-1) was identified and the biochemical properties of the recombinant enzyme were characterized. Cryptopain-1 shared common structural properties with cathepsin L-like papain family enzymes, but lacked a typical signal peptide sequence and contained a possible transmembrane domain near the amino terminus and a unique insert in the front of the mature domain. The recombinant cryptopain-1 expressed in Escherichia coli and refolded to the active form showed typical biochemical properties of cathepsin L-like enzymes. The folding determinant of cryptopain-1 was characterized through multiple constructs with or without different lengths of the pro-domain of the enzyme expressed in E. coli and assessment of their refolding abilities. All constructs, except one that did not contain the full-length mature domain, successfully refolded into the active enzymes, suggesting that cryptopain-1 did not require the pro-domain for folding. Western blot analysis showed that cryptopain-1 was expressed in the sporozoites and the enzyme preferentially degraded proteins, including collagen and fibronectin, but not globular proteins. This suggested a probable role for cryptopain-1 in host cell invasion and/or egression by the parasite.

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