Purified EDEM3 or EDEM1 alone produces determinant oligosaccharide structures from M8B in mammalian glycoprotein ERAD.
eLife Sciences Publications, Ltd
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George, G., Ninagawa, S., Yagi, H., Furukawa, J., Hashii, N., Ishii-Watabe, A., Deng, Y., et al. (2021). Purified EDEM3 or EDEM1 alone produces determinant oligosaccharide structures from M8B in mammalian glycoprotein ERAD.. Elife, 10 (ARTN e70357), e70357. https://doi.org/10.7554/eLife.70357
Sequential mannose trimming of N-glycan, from M9 to M8B and then to oligosaccharides exposing the α1,6-linked mannosyl residue (M7A, M6, and M5), facilitates endoplasmic reticulum-associated degradation of misfolded glycoproteins (gpERAD). We previously showed that EDEM2 stably disulfide-bonded to the thioredoxin domain-containing protein TXNDC11 is responsible for the first step (George et al., 2020). Here, we show that EDEM3 and EDEM1 are responsible for the second step. Incubation of pyridylamine-labeled M8B with purified EDEM3 alone produced M7 (M7A and M7C), M6, and M5. EDEM1 showed a similar tendency, although much lower amounts of M6 and M5 were produced. Thus, EDEM3 is a major α1,2-mannosidase for the second step from M8B. Both EDEM3 and EDEM1 trimmed M8B from a glycoprotein efficiently. Our confirmation of the Golgi localization of MAN1B indicates that no other α1,2-mannosidase is required for gpERAD. Accordingly, we have established the entire route of oligosaccharide processing and the enzymes responsible.
biochemistry, cell biology, chemical biology, glycoprotein, human, mannose trimming, protein degradation, Calcium-Binding Proteins, Cell Line, Endoplasmic Reticulum-Associated Degradation, Glycoproteins, Humans, Membrane Proteins, Oligosaccharides, alpha-Mannosidase
External DOI: https://doi.org/10.7554/eLife.70357
This record's URL: https://www.repository.cam.ac.uk/handle/1810/332258
Attribution 4.0 International
Licence URL: https://creativecommons.org/licenses/by/4.0/