Conformation-Independent Binding of Monoglucosylated Ribonuclease B to Calnexin
1997; Cell Press; Volume: 88; Issue: 1 Linguagem: Inglês
10.1016/s0092-8674(00)81855-3
ISSN1097-4172
AutoresAndré Zapun, Ştefana M. Petrescu, Pauline M. Rudd, Raymond A. Dwek, David Y. Thomas, John Bergeron,
Tópico(s)Toxin Mechanisms and Immunotoxins
ResumoCalnexin is a membrane protein of the endoplasmic reticulum that associates transiently with newly synthesized N-linked glycoproteins in vivo. Using defined components, the binding of ribonuclease B (RNase B) Man7-Man9 glycoforms to the luminal domain of calnexin was observed in vitro only if RNase B was monoglucosylated. Binding was independent of the conformation of the glycoprotein. Calnexin protected monoglucosylated RNase B from the action of glucosidase II and PNGase F but not from that of Endo H, which completely released the protein from calnexin. These observations directly demonstrate that calnexin can act exclusively as a lectin.
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