Evolution of Multiple Chaperonins: Innovation of Evolutionary Capacitors

Abstract

Molecular chaperones and chaperonins are part of large and evolutionarily conserved protein families that are involved in a large variety of functions in the cell. Chief among these functions is their ability to assist other slow-folding proteins in acquiring their native conformation. Because of their roles in the cell, chaperonins have enthralled scientists for decades and are considered the most important quality control mechanisms of the cell. In this chapter, I present evidence that supports a remarkable expansion of chaperonin protein families through gene duplication. Because of their ability in modulating phenotype through genotype, chaperonins are potent capacitors of evolution, as they allow the survival of innovative mutations despite their destabilizing effects for protein structures. In this sense, chaperonins increase the resistance of proteins to mutations and fuel evolvability by enabling proteins for a wider exploration of genotypic network. The complexity of the range of functions in which chaperonins are involved and the latest studies magnify the importance of these molecules as moonlighting proteins involved in a wide variety of independent, however equally important, functions. Future studies will aim at understanding how these proteins give origin to novel functions and using these capacitors as a mean to define the functional landscape of the cell.