O-GlcNAcylation of tubulin inhibits its polymerization.
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.
Ji
Suena
S
Department of Biology, Yonsei University, Seoul, Korea.
Kang
Jeong Gu
JG
Park
Sang Yoon
SY
Lee
Joohun
J
Oh
Young J
YJ
Cho
Jin Won
JW
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*
D014404:Tubulin; D000117:Acetylglucosamine