title: O-GlcNAcylation of tubulin inhibits its polymerization.
abstract: The attachment of O-linked β-N-acetylglucosamine (O-GlcNAc) to proteins is an abundant and reversible modification that involves many cellular processes including transcription, translation, cell proliferation, apoptosis, and signal transduction. Here, we found that the O-GlcNAc modification pattern was altered during all-trans retinoic acid (tRA)-induced neurite outgrowth in the MN9D neuronal cell line. We identified several O-GlcNAcylated proteins using mass spectrometric analysis, including α- and β-tubulin. Further analysis of α- and β-tubulin revealed that O-GlcNAcylated peptides mapped between residues 173 and 185 of α-tubulin and between residues 216 and 238 of β-tubulin, respectively. We found that an increase in α-tubulin O-GlcNAcylation reduced heterodimerization and that O-GlcNAcylated tubulin did not polymerize into microtubules. Consequently, when O-GlcNAcase inhibitors were co-incubated with tRA, the extent of neurite outgrowth was decreased by 20% compared to control. Thus, our data indicate that the O-GlcNAcylation of tubulin negatively regulates microtubule formation.
authors.affiliation: Department of Biology, Yonsei University, Seoul, Korea.
authors.forename: Suena
authors.initials: S
authors.lastname: Ji
authors.forename: Jeong Gu
authors.initials: JG
authors.lastname: Kang
authors.forename: Sang Yoon
authors.initials: SY
authors.lastname: Park
authors.forename: Joohun
authors.initials: J
authors.lastname: Lee
authors.forename: Young J
authors.initials: YJ
authors.lastname: Oh
authors.forename: Jin Won
authors.initials: JW
authors.lastname: Cho
mesh_terms: D000117:Acetylglucosamine / Q000378:metabolism*; D000595:Amino Acid Sequence; D002460:Cell Line; D015536:Down-Regulation; D006031:Glycosylation; D057809:HEK293 Cells; D006801:Humans; D008870:Microtubules / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D058105:Polymerization; D014404:Tubulin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D014404:Tubulin; D000117:Acetylglucosamine