A new key player to control microtubule polymerisation dynamics

Dynamic microtubules are critical in various cellular events such as mitosis. In this study, we identified a novel Drosophila protein, Sentin, that localises to growing ends of microtubules and makes microtubules dynamic.

HFSP Career Development Award holder Gohta Goshima and colleagues
authored on Thu, 07 July 2011

The polymerisation dynamics of microtubules is critical for their biological functions, and is regulated by microtubule-associated proteins in vivo.  A key factor, previously identified, is the highly conserved EB1 protein that localises to microtubule plus-ends autonomously, recruits >10 other cargo proteins to the ends, and is critical for making dynamic microtubules in vivo.  However, it has been unclear how this master regulator of microtubule plus ends promotes microtubule dynamics. 

Figure:  Sentin (green) is localised at the growing ends of microtubules (red).  Blue; DNA. 

In this study, we identified a novel EB1-binding protein, Sentin (see Figure).  Sentin depletion in Drosophila S2 cells, similar to EB1 depletion, resulted in an increase in microtubule pausing without displacing EB1 from growing microtubule ends.  We demonstrated that Sentin’s association with EB1 was critical for its plus-end localisation and function; furthermore, the EB1 phenotype was rescued by expressing an EBN-Sentin fusion protein in which the C-terminal cargo-binding region of EB1 is replaced with Sentin.  Finally, Sentin RNAi attenuated plus-end accumulation of Msps, the orthologue of XMAP215 microtubule polymerase. 

These results indicate that EB1 promotes dynamic microtubule behaviour by recruiting the dominant cargo protein Sentin and possibly also a microtubule polymerase to the microtubule tip.

References

EB1 promotes microtubule dynamics by recruiting Sentin in Drosophila cells.  Li W, Miki T, Watanabe T, Kakeno M, Sugiyama I, Kaibuchi K, Goshima G. (2011)
  J Cell Biol. 193:973-83.

 

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