Cathepsin Release from Lysosomes Promotes Endocytosis of Clostridium perfringens Iota-Toxin

Iota-toxin from Clostridium perfringens type E is a binary toxin composed of two independent proteins: actin-ADP-ribosylating enzyme component, iota-a (Ia), and binding component, iota-b (Ib). Ib binds to target cell receptors and mediates the internalization of Ia into the cytoplasm. Extracellular lysosomal enzyme acid sphingomyelinase (ASMase) was previously shown to facilitate the internalization of iota-toxin. In this study, we investigated how lysosomal cathepsin promotes the internalization of iota-toxin into target cells. Cysteine protease inhibitor E64 prevented the cytotoxicity caused by iota-toxin, but aspartate protease inhibitor pepstatin-A and serine protease inhibitor AEBSF did not. Knockdown of lysosomal cysteine protease cathepsins B and L decreased the toxin-induced cytotoxicity. E64 suppressed the Ib-induced ASMase activity in extracellular fluid, showing that the proteases play a role in ASMase activation. These results indicate that cathepsin B and L facilitate entry of iota-toxin via activation of ASMase.

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Faculty Opinions recommendation of VEGF-A induces angiogenesis by perturbing the cathepsin-cysteine protease inhibitor balance in venules, causing basement membrane degradation and mother vessel formation.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1162504.624035 ◽

2009 ◽

Author(s):

Andrius Kazlauskas

Keyword(s):

Basement Membrane ◽

Protease Inhibitor ◽

Cysteine Protease ◽

Cysteine Protease Inhibitor ◽

Membrane Degradation ◽

Vessel Formation ◽

Basement Membrane Degradation

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A Novel Cysteine Protease Inhibitor of Naegleria fowleri That Is Specifically Expressed during Encystation and at Mature Cysts

Pathogens ◽

10.3390/pathogens10040388 ◽

2021 ◽

Vol 10 (4) ◽

pp. 388

Author(s):

Hương Giang Lê ◽

A-Jeong Ham ◽

Jung-Mi Kang ◽

Tuấn Cường Võ ◽

Haung Naw ◽

...

Keyword(s):

Protease Inhibitor ◽

Cysteine Protease ◽

Expression Profiles ◽

Critical Role ◽

Cyst Formation ◽

Cysteine Proteases ◽

Cysteine Protease Inhibitor ◽

Naegleria Fowleri ◽

Nægleria Fowleri ◽

Cystatin Family

Naegleria fowleri is a free-living amoeba that is ubiquitous in diverse natural environments. It causes a fatal brain infection in humans known as primary amoebic meningoencephalitis. Despite the medical importance of the parasitic disease, there is a great lack of knowledge about the biology and pathogenicity of N. fowleri. In this study, we identified and characterized a novel cysteine protease inhibitor of N. fowleri (NfCPI). NfCPI is a typical cysteine protease inhibitor belonging to the cystatin family with a Gln-Val-Val-Ala-Gly (QVVAG) motif, a characteristic motif conserved in the cystatin family of proteins. Bacterially expressed recombinant NfCPI has a dimeric structure and exhibits inhibitory activity against several cysteine proteases including cathespin Bs of N. fowleri at a broad range of pH values. Expression profiles of nfcpi revealed that the gene was highly expressed during encystation and cyst of the amoeba. Western blot and immunofluorescence assays also support its high level of expression in cysts. These findings collectively suggest that NfCPI may play a critical role in encystation or cyst formation of N. fowleri by regulating cysteine proteases that may mediate encystation or mature cyst formation of the amoeba. More comprehensive studies to investigate the roles of NfCPI in encystation and its target proteases are necessary to elucidate the regulatory mechanism and the biological significance of NfCPI.

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Molecular Modeling in Cysteine Protease Inhibitor Design

Current Pharmaceutical Design ◽

10.2174/1381612023394142 ◽

2002 ◽

Vol 8 (18) ◽

pp. 1673-1681 ◽

Cited By ~ 6

Author(s):

Mika Lindvall

Keyword(s):

Molecular Modeling ◽

Protease Inhibitor ◽

Cysteine Protease ◽

Cysteine Protease Inhibitor ◽

Inhibitor Design

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A novel cysteine protease inhibitor with lectin activity from the epidermis of the Japanese eel Anguilla japonica

Comparative Biochemistry and Physiology Part B Biochemistry and Molecular Biology ◽

10.1016/j.cbpc.2005.02.002 ◽

2005 ◽

Vol 141 (1) ◽

pp. 103-109 ◽

Cited By ~ 12

Author(s):

Eiichi Saitoh ◽

Satoko Isemura ◽

Akira Chiba ◽

Shunya Oka ◽

Shoji Odani

Keyword(s):

Protease Inhibitor ◽

Cysteine Protease ◽

Anguilla Japonica ◽

Japanese Eel ◽

Cysteine Protease Inhibitor ◽

Lectin Activity

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Binding Component of Clostridium perfringens Iota-Toxin Induces Endocytosis in Vero Cells

Infection and Immunity ◽

10.1128/iai.70.4.1909-1914.2002 ◽

2002 ◽

Vol 70 (4) ◽

pp. 1909-1914 ◽

Cited By ~ 47

Author(s):

Masahiro Nagahama ◽

Koichi Nagayasu ◽

Keiko Kobayashi ◽

Jun Sakurai

Keyword(s):

Clostridium Perfringens ◽

Vero Cells ◽

Binary Toxin ◽

Wild Type ◽

Oligomer Formation ◽

Clostridium Perfringens Iota Toxin ◽

Binding Component ◽

Pronase Treatment

ABSTRACT Clostridium perfringens iota-toxin is a binary toxin consisting of two individual proteins, the binding component (Ib) and the enzyme component (Ia). Wild-type Ib bound to Vero cells at 4 and 37°C and formed oligomers at 37°C but not at 4°C. The Ib-induced K+ release from the cells was dependent on the oligomer formation of Ib in the cells, but the oligomer formation did not induce rounding activity or cytotoxicity. After incubation of the cells with recombinant Ib (rIb) at 37°C, the Ib oligomer in the cell became resistant to pronase treatment with time, but the Ib monomer was sensitive to the treatment. Furthermore, treatment of Vero cells with rIb in the presence of bafilomycin, methylamine, or ethylamine resulted in accumulation of the oligomer in the cells but had no effect on K+ release. Moreover, incubation with Ib plus Ia in the presence of these agents caused no rounding in the cells. These observations suggest that Ib binds to Vero cells, itself oligomerizing to form ion-permeable channels and that the formation of oligomer then induces endocytosis.

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