The Martindale lab published a new paper entitled “Evidence for an early cadherin-catenin network in ctenophores” in the journal Molecular Biology and Evolution.
Multicellular animals, called metazoans, arose from unicellular ancestors. The evolution of multicellularity required coordination and physical contact among cells. Thus, cell-to-cell adhesion is fundamental to the evolution of all animals on Earth today. The cadherin-catenin complex (CCC) is a calcium-dependent protein assembly that plays a central role in cell adhesion, tissue organization, and signaling. Although the CCC is highly conserved across animals, its occurrence in ctenophores, one of the earliest branching groups, has remained uncertain, with implications for understanding the origins of multicellularity in animals.
Using comparative genomic analyses, they identified a ctenophore-specific cadherin that retains conserved molecular features of the CCC. To investigate putative interactions between the CCC members, they screened a custom Yeast 2-hybrid library generated from Mnemiopsis leidyi embryos, and found conserved interactions among key CCC components, including β-catenin, p120, and actin cytoskeleton-associated partners. Their data were further validated by site-directed mutagenesis of conserved residues that abolished interactions, mirroring observations in other animals.
Together, these findings suggest that core molecular interactions underlying the CCC are conserved in M. leidyi, consistent with the hypothesis that the CCC may have contributed to the emergence of the first tissue types in multicellular animals.
This work resulted from a fruitful collaboration with the Senatore lab at the University of Toronto-Mississauga (Canada).
The full paper can be found at the following link: https://doi.org/10.1093/molbev/msag123