First published online April 23, 2008
Journal of Cell Science 121, 901e (2008)
© The Company of Biologists Limited
Bik1p goes it alone?
Bik1p is the budding-yeast orthologue of the mammalian CLIP-170 microtubule (MT) plus-end tracking protein. It is currently thought that Bik1p is transported towards the plus ends of MTs in a complex with the kinesin Kip2p. Dynein is then recruited at MT plus ends by Bik1p, and the Bik1p-dynein complex tracks plus ends principally as a cargo of Kip2p. On page 1506, Cécile Boscheron and colleagues test this model by examining the localization of Bik1p in yeast strains that express Glu tubulin, a mutant form of 
-tubulin that cannot interact with Bik1p. The authors show that, in these strains, Bik1p fails to track plus ends, despite the presence of a robust Kip2p signal at the plus ends. Dynein positioning at the same plus ends is unperturbed. The evidence suggests that, although Kip2p mediates the transport of Bik1p towards MT plus ends, Bik1p plus-end tracking requires the interaction of Bik1p with tubulin. Moreover, dynein is transported at MT plus ends in a Kip2p-Bik1p-dependent manner and can subsequently track MT plus ends even following depletion of Bik1p at those ends. Thus, although Bik1p is brought to MT plus ends by Kip2p, MT end tracking by Bik1p and Kip1p are distinct processes.
Related articles in JCS:
- A new role for kinesin-directed transport of Bik1p (CLIP-170) in Saccharomyces cerevisiae
- Fabrice Caudron, Annie Andrieux, Didier Job, and Cécile Boscheron
JCS 2008 121: 1506-1513.
[Abstract]
[Full Text]
