title: 3D structural analysis of protein O-mannosyl kinase, POMK, a causative gene product of dystroglycanopathy.
abstract: Orchestration of the multiple enzymes engaged in O-mannose glycan synthesis provides a matriglycan on α-dystroglycan (α-DG) which attracts extracellular matrix (ECM) proteins such as laminin. Aberrant O-mannosylation of α-DG leads to severe congenital muscular dystrophies due to detachment of ECM proteins from the basal membrane. Phosphorylation at C6-position of O-mannose catalyzed by protein O-mannosyl kinase (POMK) is a crucial step in the biosynthetic pathway of O-mannose glycan. Several mis-sense mutations of the POMK catalytic domain are known to cause a severe congenital muscular dystrophy, Walker-Warburg syndrome. Due to the low sequence similarity with other typical kinases, structure-activity relationships of this enzyme remain unclear. Here, we report the crystal structures of the POMK catalytic domain in the absence and presence of an ATP analogue and O-mannosylated glycopeptide. The POMK catalytic domain shows a typical protein kinase fold consisting of N- and C-lobes. Mannose residue binds to POMK mainly via the hydroxyl group at C2-position, differentiating from other monosaccharide residues. Intriguingly, the two amino acid residues K92 and D228, interacting with the triphosphate group of ATP, are donated from atypical positions in the primary structure. Mutations in this protein causing muscular dystrophies can now be rationalized.
authors.affiliation: Structural Glycobiology Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center, RIKEN Global Research Cluster, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
authors.forename: Masamichi
authors.initials: M
authors.lastname: Nagae
authors.affiliation: Structural Glycobiology Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center, RIKEN Global Research Cluster, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
authors.forename: Sushil K
authors.initials: SK
authors.lastname: Mishra
authors.affiliation: Graduate School of Medical Life Science, Yokohama City University, Tsurumi, Yokohama, 230-0045, Japan.
authors.forename: Makiko
authors.initials: M
authors.lastname: Neyazaki
authors.affiliation: Graduate School of Medical Life Science, Yokohama City University, Tsurumi, Yokohama, 230-0045, Japan.
authors.forename: Rika
authors.initials: R
authors.lastname: Oi
authors.affiliation: Structural Glycobiology Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center, RIKEN Global Research Cluster, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
authors.forename: Akemi
authors.initials: A
authors.lastname: Ikeda
authors.affiliation: Structural Biology Research Center, High Energy Accelerator Research Organization, Tsukuba, 305-0801, Japan.
authors.forename: Naohiro
authors.initials: N
authors.lastname: Matsugaki
authors.affiliation: Graduate School of Medical Life Science, Yokohama City University, Tsurumi, Yokohama, 230-0045, Japan.
authors.forename: Satoko
authors.initials: S
authors.lastname: Akashi
authors.affiliation: Molecular Glycobiology, Research Team for Mechanism of Aging, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Itabashi-ku, Tokyo, 173-0015, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Manya
authors.affiliation: The Noguchi Institute, 1-9-7, Kaga, Itabashi-ku, Tokyo, 173-0003, Japan.
authors.forename: Mamoru
authors.initials: M
authors.lastname: Mizuno
authors.affiliation: Graduate School of Pharmaceutical Sciences, Nagoya City University, Mizuho-ku, Nagoya, 467-8603, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Yagi
authors.affiliation: Graduate School of Pharmaceutical Sciences, Nagoya City University, Mizuho-ku, Nagoya, 467-8603, Japan.|Okazaki Institute for Integrative Bioscience and Institute for Molecular Sciences, National Institutes of Natural Sciences, Okazaki, 444-8787, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Kato
authors.affiliation: Structural Biology Research Center, High Energy Accelerator Research Organization, Tsukuba, 305-0801, Japan.
authors.forename: Toshiya
authors.initials: T
authors.lastname: Senda
authors.affiliation: Molecular Glycobiology, Research Team for Mechanism of Aging, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Itabashi-ku, Tokyo, 173-0015, Japan.
authors.forename: Tamao
authors.initials: T
authors.lastname: Endo
authors.affiliation: Graduate School of Medical Life Science, Yokohama City University, Tsurumi, Yokohama, 230-0045, Japan.
authors.forename: Terukazu
authors.initials: T
authors.lastname: Nogi
authors.affiliation: Structural Glycobiology Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center, RIKEN Global Research Cluster, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Yamaguchi
mesh_terms: D000818:Animals; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D049030:Dystroglycans / Q000737:chemistry; D006801:Humans; D051379:Mice; D009136:Muscular Dystrophies / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D011494:Protein Kinases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D049030:Dystroglycans; C583116:POMK protein, human; C000617172:POMK protein, mouse; D011494:Protein Kinases