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Journal article
Calpain-dependent endoproteolytic cleavage of PrPSc modulates scrapie prion propagation
Journal of Biological Chemistry, Vol.279, pp.21948-21956
279
2004
PMID: 15026410
Web of Science ID: WOS:000221417100035
Abstract
Previous studies using post-mortem human brain ex-tracts demonstrated that PrP in Creutzfeldt-Jakob disease (CJD) brains is cleaved by a cellular protease to generate a C-terminal fragment, referred to as C2, which has the same molecular weight as PrP-(27–30), the protease-resistant core of PrPSc (1). The role of this endoproteolytic cleavage of PrP in prion pathogenesis and the identity of the cellular protease responsible for production of the C2 cleavage product has not been ex-
plored. To address these issues we have taken a combination of pharmacological and genetic approaches using persistently infected scrapie mouse brain (SMB) cells. We confirm that production of C2 is the predominant cleavage event of PrPSc in the brains of scrapie-infected mice and that SMB cells faithfully recapitulate the diverse intracellular proteolytic processing events of PrPSc and PrPC observed in vivo. While increases in intracellular calcium (Ca2) levels in prion-infected cell cultures stimulate the production of the PrPSc cleavage product, pharmacological inhibitors of calpains and overexpression of the endogenous calpain inhibitor, calpastatin, prevent the production of C2. In contrast, inhibitors of lysosomal proteases, caspases, and the proteasome have no effect on C2 production in SMB cells. Calpain inhibition also prevents the accumulation of PrPSc in SMB and persistently infected ScN2A cells, whereas bioassay of inhibitor-treated cell cultures demonstrates that calpain inhibition results in reduced prion titers compared with control-treated cultures assessed in parallel. Our observations suggest that calpain-mediated endoproteolytic cleavage of PrPSc may be an important event in prion propagation.
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- Title
- Calpain-dependent endoproteolytic cleavage of PrPSc modulates scrapie prion propagation
- Publication Details
- Journal of Biological Chemistry, Vol.279, pp.21948-21956
- Resource Type
- Journal article
- Publisher
- The American Society for Biochemistry and Molecular Biology, Inc.; United States
- Series
- 279
- Copyright
- This is an Open Access article under the CC BY license.
- Identifiers
- WOS:000221417100035; 99380090773006600
- Academic Unit
- Biology; Hal Marcus College of Science and Engineering
- Language
- English