The C terminus of mitosin is essential for its nuclear localization, centromere/kinetochore targeting, and dimerization

J Biol Chem. 1995 Aug 18;270(33):19545-50. doi: 10.1074/jbc.270.33.19545.

Abstract

Mitosin is a novel 350-kDa nuclear phosphoprotein that dramatically relocates from the evenly nuclear distribution in S phase to the centromere/kinetochore and mitotic apparatus in M phase. The dynamic relocalization of mitosin is accompanied by the phosphorylation of itself, suggesting that mitosin plays a role in mitotic progression. The molecular basis of nuclear localization and targeting of mitosin to the centromere/kinetochore were characterized using a set of epitope-tagged deletion mutants. The data indicate that the extreme C terminus (amino acids 2,487-3,113) of mitosin has both an independent centromere/kinetochore targeting domain and an unusually spaced bipartite nuclear localization signal. Moreover, the same centromere/kinetochore targeting domain was shown to be essential for the ability of mitosin to bind to itself or other putative mitosin-associated proteins through use of the yeast two-hybrid system. These results suggest that the C terminus of the mitosin is essential for its role in influencing cell cycle progression.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Biological Transport
  • Biopolymers
  • Cell Line
  • Cell Nucleus / metabolism*
  • Centromere / metabolism*
  • Chromosomal Proteins, Non-Histone*
  • HeLa Cells
  • Humans
  • Kinetochores / metabolism*
  • Mice
  • Microfilament Proteins
  • Microscopy, Immunoelectron
  • Mitosis
  • Molecular Sequence Data
  • Nuclear Proteins / chemistry
  • Nuclear Proteins / metabolism*
  • Phosphoproteins / chemistry
  • Phosphoproteins / metabolism*
  • Signal Transduction

Substances

  • Biopolymers
  • Chromosomal Proteins, Non-Histone
  • Microfilament Proteins
  • Nuclear Proteins
  • Phosphoproteins
  • centromere protein F