The architecture of CCAN proteins creates a structural integrity to resist spindle forces and achieve proper Intrakinetochore stretch

Dev Cell. 2014 Sep 29;30(6):717-30. doi: 10.1016/j.devcel.2014.08.003.


Constitutive centromere-associated network (CCAN) proteins, particularly CENP-C, CENP-T, and the CENP-H/-I complex, mechanically link CENP-A-containing centromeric chromatin within the inner kinetochore to outer kinetochore proteins, such as the Ndc80 complex, that bind kinetochore microtubules. Accuracy of chromosome segregation depends critically upon Aurora B phosphorylation of Ndc80/Hec1. To determine how CCAN protein architecture mechanically constrains intrakinetochore stretch between CENP-A and Ndc80/Hec1 for proper Ndc80/Hec1 phosphorylation, we used super-resolution fluorescence microscopy and selective protein depletion. We found that at bi-oriented chromosomes in late prometaphase cells, CENP-T is stretched ∼16 nm to the inner end of Ndc80/Hec1, much less than expected for full-length CENP-T. Depletion of various CCAN linker proteins induced hyper-intrakinetochore stretch (an additional 20-60 nm) with corresponding significant decreases in Aurora B phosphorylation of Ndc80/Hec1. Thus, proper intrakinetochore stretch is required for normal kinetochore function and depends critically on all the CCAN mechanical linkers to the Ndc80 complex.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aurora Kinase B / metabolism
  • Autoantigens / metabolism*
  • Centromere Protein A
  • Chromosomal Proteins, Non-Histone / metabolism*
  • Cytoskeletal Proteins
  • HeLa Cells
  • Humans
  • Kinetochores / metabolism*
  • Nuclear Proteins / metabolism
  • Phosphorylation
  • Protein Binding
  • Spindle Apparatus / metabolism*


  • Autoantigens
  • CENPA protein, human
  • CENPT protein, human
  • Centromere Protein A
  • Chromosomal Proteins, Non-Histone
  • Cytoskeletal Proteins
  • NDC80 protein, human
  • Nuclear Proteins
  • Aurora Kinase B