BubR1 is modified by sumoylation during mitotic progression

J Biol Chem. 2012 Feb 10;287(7):4875-82. doi: 10.1074/jbc.M111.318261. Epub 2011 Dec 13.

Abstract

BubR1 functions as a crucial component that monitors proper chromosome congression and mitotic timing during cell division. We investigated molecular regulation of BubR1 and found that BubR1 was modified by an unknown post-translation mechanism during the cell cycle, resulting in a significant mobility shift on denaturing gels. We termed it BubR1-M as the nature of modification was not characterized. Extended (>24 h) treatment of HeLa cells with a microtubule disrupting agent including nocodazole and taxol or release of mitotic shake-off cells into fresh medium induced BubR1-M. BubR1-M was derived from neither phosphorylation nor acetylation. Ectopic expression coupled with pulling down analyses showed that BubR1-M was derived from SUMO modification. Mutation analysis revealed that lysine 250 was a crucial site for sumoylation. Significantly, compared with the wild-type control, ectopic expression of a sumoylation-deficient mutant of BubR1 induced chromosomal missegregation and mitotic delay. Combined, our study identifies a new type of post-translational modification that is essential for BubR1 function during mitosis.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Acetylation
  • Amino Acid Substitution
  • HeLa Cells
  • Humans
  • Microtubules / genetics
  • Microtubules / metabolism
  • Mitosis / physiology*
  • Mutation, Missense
  • Phosphorylation / physiology
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism*
  • SUMO-1 Protein / genetics
  • SUMO-1 Protein / metabolism
  • Sumoylation / physiology*

Substances

  • SUMO-1 Protein
  • BUB1 protein, human
  • Bub1 spindle checkpoint protein
  • Protein-Serine-Threonine Kinases