Asymmetric cortical and nuclear localizations of WRM-1/beta-catenin during asymmetric cell division in C. elegans.

beta-Catenin can promote adhesion at the cell cortex and mediate Wnt signaling in the nucleus. We show that, in Caenorhabditis elegans, both WRM-1/beta-catenin and LIT-1 kinase localize to the anterior cell cortex during asymmetric cell division but to the nucleus of the posterior daughter afterward. Both the cortical and nuclear localizations are regulated by Wnts and are apparently coupled. We also found that the daughters show different nuclear export rates for LIT-1. Our results indicate that Wnt signals release cortical WRM-1 from the posterior cortex to generate cortical asymmetry that may control WRM-1 asymmetric nuclear localization by regulating cell polarity.