Structure-specific recognition protein 1 facilitates microtubule growth and bundling required for mitosis

Mol Cell Biol. 2010 Feb;30(4):935-47. doi: 10.1128/MCB.01379-09. Epub 2009 Dec 7.


Tight regulation of microtubule (MT) dynamics is essential for proper chromosome movement during mitosis. Here we show, using mammalian cells, that structure-specific recognition protein 1 (SSRP1) is a novel regulator of MT dynamics. SSRP1 colocalizes with the spindle and midbody MTs, and associates with MTs both in vitro and in vivo. Purified SSRP1 facilitates tubulin polymerization and MT bundling in vitro. Knockdown of SSRP1 inhibits the growth of MTs and leads to disorganized spindle structures, reduction of K-fibers and midbody fibers, disrupted chromosome movement, and attenuated cytokinesis in vivo. These results demonstrate that SSRP1 is crucial for MT growth and spindle assembly during mitosis.

Publication types

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

MeSH terms

  • Cell Line
  • Chromosome Segregation
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • High Mobility Group Proteins / genetics
  • High Mobility Group Proteins / metabolism*
  • Humans
  • Microscopy, Electron, Transmission
  • Microtubules / metabolism*
  • Microtubules / ultrastructure
  • Mitosis*
  • Protein Binding
  • Spindle Apparatus / metabolism
  • Transcriptional Elongation Factors / genetics
  • Transcriptional Elongation Factors / metabolism*


  • DNA-Binding Proteins
  • High Mobility Group Proteins
  • SSRP1 protein, human
  • Transcriptional Elongation Factors