Analyses of N-linked glycans of PrPSc revealed predominantly 2,6-linked sialic acid residues
PublisherBlackwell Publishing Ltd
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AbstractMammalian prions (PrPSc) consist of misfolded, conformationally altered, self-replicating states of the sialoglycoprotein called prion protein or PrPC. Recent studies revealed that the sialylation status of PrPSc plays a major role in evading innate immunity and infecting a host. Establishing the type of linkage by which sialic acid residues are attached to galactose is important, as it helps to identify the sialyltransferases responsible for sialylating PrPC and outline strategies for manipulating the sialyation status of PrPSc. Using enzymatic treatment with sialidases and lectin blots, this study demonstrated that in N-linked glycans of PrPSc, the sialic acid residues are predominantly alpha 2,6-linked. High percentages of alpha 2,6-linked sialic acids were observed in PrPSc of three prion strains 22L, RML, and ME7, as well as PrPSc from brain, spleen, or N2a cells cultured in vitro. Moreover, the variation in the percentage of alpha 2,3- versus 2,6-linked sialic acid was found to be relatively minor between brain-, spleen-, or cell-derived PrPSc, suggesting that the type of linkage is independent of tissue type. Based on the current results, we propose that sialyltransferases of St6Gal family, which is responsible for attaching sialic acids via alpha 2,6-linkages to N-linked glycans, controls sialylation of PrPC and PrPSc.
SponsorsThis study was carried out in strict accordance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health. The animal protocol was approved by the Institutional Animal Care and Use Committee of the University of Maryland, Baltimore (assurance no. A32000-01, permit no. 0215002).
Identifier to cite or link to this itemhttps://www.scopus.com/inward/record.uri?eid=2-s2.0-85033385873&doi=10.1111%2ffebs.14268&partnerID=40&md5=f7c3512830e3dd8859253984cb00bf36; http://hdl.handle.net/10713/10963