First published online January 10, 2008
Journal of Cell Science 121, 201e (2008)
© The Company of Biologists Limited
Dynactin dynamics in division
Cells divide asymmetrically during early embryogenesis, which allows them to establish distinct cell lineages. Prior to division, cellular components must be distributed in a polarised manner within the cytosol, and the mitotic spindle must rotate until it is oriented along the axis of cell polarity. In the Caenorhabditis elegans embryo at the four-cell stage, cell-cell contact between the neighbouring EMS and P2 cells is necessary to polarise EMS, but how it does so is uncertain. On page 155, John White and colleagues describe the role of dynactin, the binding partner of the cytoskeletal motor protein dynein, in spindle alignment in EMS. By expressing components of the dynactin complex as GFP-fusion proteins, the authors show that dynactin accumulates at the plasma membrane on the P2-EMS border before and during spindle rotation. This does not occur when Wnt and Src signalling pathways are disrupted. Moreover, the authors provide evidence that dynactin, probably in complex with dynein, is activated by G-protein signalling. The authors propose that the dynactin-dynein complex exerts force on spindle-associated microtubules to pull the spindle into the correct orientation.
Related articles in JCS:
- Src and Wnt signaling regulate dynactin accumulation to the P2-EMS cell border in C. elegans embryos
- Haining Zhang, Ahna R. Skop, and John G. White
JCS 2008 121: 155-161.
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