Cell polarity: new PARtners for Cdc42 and Rac

Three recent papers have reported the surprising finding that Cdc42 and Rad, both of which are known to be involved in maintaining apico-basolateral polarity of epithelial cells, can each bind to a protein complex containing Par6, Par3 and PKC zeta. These latter three proteins have known functions in the polarization of mother cells before asymmetric cell division in Caenorhabditis elegans. These latest results indicate a possible link between the mechanisms used to maintain cell polarity and to set up asymmetric cell divisions.