N-Linked glycosylation of the superoxide-producing NADPH oxidase Nox1.
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Miyano K, Sumimoto H
N-Linked glycosylation of the superoxide-producing NADPH oxidase Nox1.
Biochem Biophys Res Commun. 2014 Jan 17;443(3):1060-5. doi: 10.1016/j.bbrc.2013.12.086. Epub 2013 Dec 21.
- PubMed ID
- 24365146 [ View in PubMed]
- Abstract
Nox1 is a membrane-integrated protein that belongs to the Nox family of superoxide-producing NADPH oxidases. Here we show that human Nox1 undergoes glycosylation at Asn-162 and Asn-236 in the second and third extracellular loops, respectively. Simultaneous threonine substitution for these residues completely abrogates the glycosylation, but does not prevent Nox1 from forming a heterodimer with p22(phox), trafficking to the cell surface, or producing superoxide. In the absence of p22(phox), Nox1 is transported to the plasma membrane mainly as a form with high mannose N-glycans, although their conversion into complex N-glycans is induced by expression of p22(phox). These findings indicate that glycosylation and subsequent N-glycan maturation of Nox1 are both dispensable for its cell surface recruitment. Superoxide production by unglycosylated Nox1 is largely dependent on p22(phox), which is abrogated by glutamine substitution for Pro-156 in p22(phox), a mutation leading to a defective interaction with the Nox1-activating protein Noxo1. Thus p22(phox) directly contributes to Nox1 activation in a glycosylation-independent manner, besides its significant role in Nox1 glycan maturation.