C. elegans PAR proteins function by mobilizing and stabilizing asymmetrically localized protein complexes.

Background: The PAR proteins are part of an ancient and widely conserved machinery for polarizing cells during animal development. Here we use a combination of genetics and live imaging methods in the model organism Caenorhabditis elegans to dissect the cellular mechanisms by which PAR proteins polarize cells.

Results: We demonstrate two distinct mechanisms by which PAR proteins polarize the C.