A transphyletic study of metazoan β-catenin protein complexes

{beta}-catenin is essential for various biological processes, such as body axis determination and cell differentiation, during embryonic development in metazoans. {beta}-catenin functions are thought to be exerted through complexes formed with various types of proteins. Although {beta}-catenin complex proteins have been identified in several bilaterians, little is known about the structural and functional properties of {beta}-catenin complexes in early metazoan evolution. In this study, we performed a comparative analysis of {beta}-catenin sequences in nonbilaterian lineages that diverged early in metazoan evolution. We also carried out transphyletic function experiments with {beta}-catenin from nonbilaterian metazoans using developing Xenopus embryos, which included secondary axis induction in embryos and proteomic analysis of {beta}-catenin protein complexes. Comparative functional analysis of nonbilaterian {beta}-catenins demonstrated sequence characteristics important for {beta}-catenin functions, and the deep origin and evolutionary conservation of the cadherin-catenin complex. Proteins co-immunoprecipitated with {beta}-catenin included several proteins conserved among metazoans. These data provide new insights into the conserved repertoire of {beta}-catenin complexes.