Ozz; a new name on the long list of beta-catenin's nemeses.

In the February issue of Developmental Cell, Nastasi et al. describe Ozz, a muscle-specific ubiquitin ligase adaptor that regulates myofibril organization. Ozz appears to function in ubiquitination and degradation of membrane-bound, but not cytosolic, beta-catenin, whose turnover may be required for alignment and growth of the sarcomere, the basic contractile unit of myofibers.