PAR proteins regulate microtubule dynamics at the cell cortex in C. elegans.
BACKGROUND
The PAR proteins are known to be localized asymmetrically in polarized C. elegans, Drosophila, and human cells and to participate in several cellular processes, including asymmetric cell division and spindle orientation. Although astral microtubules are known to play roles in these processes, their behavior during these events remains poorly understood.


RESULTS
We have developed a method that makes it possible to examine the residence time of individual astral microtubules at the cell cortex of developing embryos. Using this method, we found that microtubules are more dynamic at the posterior cortex of the C. elegans embryo compared to the anterior cortex during spindle displacement. We further observed that this asymmetry depends on the PAR-3 protein and heterotrimeric G protein signaling, and that the PAR-2 protein affects microtubule dynamics by restricting PAR-3 activity to the anterior of the embryo.


CONCLUSIONS
These results indicate that PAR proteins function to regulate microtubule dynamics at the cortex during microtubule-dependent cellular processes.
Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280, USA. jeanclaude.labbe@bc.biol.ethz.ch
Jean Claude
JC
Labbé
Paul S
PS
Maddox
E D
ED
Salmon
Bob
B
Goldstein
D000818:Animals; D017173:Caenorhabditis elegans / Q000166:cytology* / Q000196:embryology* / Q000502:physiology; D029742:Caenorhabditis elegans Proteins / Q000502:physiology*; D008856:Microscopy, Fluorescence; D008870:Microtubules / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases; D034622:RNA Interference / Q000502:physiology; D011993:Recombinant Fusion Proteins / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology*; D008941:Spindle Apparatus / Q000502:physiology
D029742:Caenorhabditis elegans Proteins; D011993:Recombinant Fusion Proteins; C087977:par-2 protein, C elegans; C097238:PAR-3 protein, C elegans; D017346:Protein Serine-Threonine Kinases