The emergence of complex, multicellular organisms required innovation of biological processes facilitating a variety of new structures and functions. Comparative studies of basal metazoans and their relatives, for example, suggest that homologs of many of the genes that drove the innovation of multicellularity arose in free living ancestors of metazoans. These include several members of the extracellular matrix (ECM), a fundamental metazoan innovation that has come to play central roles in a variety of diverse functions including: respiration, feeding, reproduction, locomotion, osmoregulation, hemostasis and cognition. However, beyond their origins, the subsequent evolutionary forces that have since guided the development of systems such as the ECM have remained largely unexplored.
We are addressing this gap through a systematic study of ECM protein domains. Protein domains may be defined as autonomously folding, conserved segments of proteins. Vertebrate proteins, particularly those targeted to the extracellular milieu, are enriched for multidomain architectures whose multiple domains confer distinct physical and functional characteristics. The ECM represents an ideal system to explore how patterns of domain evolution may vary for a given class of functionally related proteins.
Cromar G, Wong KC, Loughran N, On T, Song H, Xiong X, Zhang Z, Parkinson J. (2014) New tricks for "old" domains: how novel architectures and promiscuous hubs contributed to the organization and evolution of the ECM. Genome Biol Evol. 6(10):2897-917.