The Cotranslational Maturation Program for the Type II Membrane Glycoprotein Influenza Neuraminidase
UMass Chan Affiliations
Department of Biochemistry and Molecular Biology.Graduate School of Biomedical Sciences
Document Type
Journal ArticlePublication Date
2008-10-14
Metadata
Show full item recordAbstract
The earliest steps in nascent protein maturation greatly affect its overall efficiency. Constraints placed on maturing proteins at these early stages limit available conformations and help to direct the native maturation process. For type II membrane proteins, these cotranslational constraints include N- and C-terminal membrane tethering, chaperone binding, and disulfide bond formation. The cotranslational maturation process for the type II membrane glycoprotein influenza neuraminidase (NA) was investigated to provide a deeper understanding of these initial endoplasmic reticulum events. The type II orientation provides experimental advantages to monitor the first maturation steps. Calnexin was shown to cotranslationally interact with NA prior to calreticulin. These interactions were required for the efficient maturation of NA as it prematurely formed intramolecular disulfides and aggregated when calnexin and calreticulin interactions were abolished. Lectin chaperone binding slowed the NA maturation process, increasing its fidelity. Carbohydrates were required for NA maturation in a regio-specific manner. A subset of NA formed intermolecular disulfides and oligomerized cotranslationally. This fraction increased in the absence of calnexin and calreticulin binding. NA dimerization also occurred for an NA mutant lacking the critical large loop disulfide bond, indicating that dimerization did not require proper NA oxidation. The strict evaluation of proper maturation carried out by the quality control machinery was instilled at the tetramerization step. This study illustrates the type II membrane protein maturation process and shows how important cotranslational events contribute to the proper cellular maturation of glycoproteins.Source
J Biol Chem. 2008 Dec 5;283(49):33826-37. Epub 2008 Oct 10. Link to article on publisher's siteDOI
10.1074/jbc.M806897200Permanent Link to this Item
http://hdl.handle.net/20.500.14038/33016PubMed ID
18849342; 18849342Related Resources
Link to Article in PubMedae974a485f413a2113503eed53cd6c53
10.1074/jbc.M806897200