Download MendeleyDiscovery of a lectin domain that regulates enzyme activity in mouse N-acetylglucosaminyltransferase-IVa (MGAT4A).
Nagae, M., Hirata, T., Tateno, H., Mishra, S.K., Manabe, N., Osada, N., Tokoro, Y., Yamaguchi, Y., Doerksen, R.J., Shimizu, T., Kizuka, Y.(2022) Commun Biol 5: 695-695
- PubMed: 35854001
- DOI: https://doi.org/10.1038/s42003-022-03661-w
- Primary Citation of Related Structures:
7VMT - PubMed Abstract:
N-Glycosylation is a common post-translational modification, and the number of GlcNAc branches in N-glycans impacts glycoprotein functions. N-Acetylglucosaminyltransferase-IVa (GnT-IVa, also designated as MGAT4A) forms a β1-4 GlcNAc branch on the α1-3 mannose arm in N-glycans. Downregulation or loss of GnT-IVa causes diabetic phenotypes by dysregulating glucose transporter-2 in pancreatic β-cells. Despite the physiological importance of GnT-IVa, its structure and catalytic mechanism are poorly understood. Here, we identify the lectin domain in mouse GnT-IVa's C-terminal region. The crystal structure of the lectin domain shows structural similarity to a bacterial GlcNAc-binding lectin. Comprehensive glycan binding assay using 157 glycans and solution NMR reveal that the GnT-IVa lectin domain selectively interacts with the product N-glycans having a β1-4 GlcNAc branch. Point mutation of the residue critical to sugar recognition impairs the enzymatic activity, suggesting that the lectin domain is a regulatory subunit for efficient catalytic reaction. Our findings provide insights into how branching structures of N-glycans are biosynthesized.
Organizational Affiliation:
Department of Molecular Immunology, Research Institute for Microbial Diseases, Osaka University, Suita, Japan. mnagae@biken.osaka-u.ac.jp.
