Across the Tree of Life, life’s phenotypic diversity has been accompanied by a massive expansion of the protein universe. Compared with simple prokaryotes that harbor thousands of proteins, plants and animals harbor hundreds of thousands of proteins that are also longer, multidomain, and comprise a variety of folds and fold combinations, repeated segments, and beta-rich architectures that make them prone to misfolding and aggregation. Surprisingly, the relative representation of core chaperones, those dedicated to maintaining the folding quality of these increasingly complex proteomes, did not change from prokaryotic to mammalian genomes. To reconcile the expanding proteomes, core chaperones have rather increased in cellular abundance and evolved to function cooperatively as a network, combined with their supporting workforce, the cochaperones.On the evolution of chaperones and cochaperones and the expansion of proteomes across the Tree of Life Mathieu E. Rebeaud, Saurav Mallik, Pierre Goloubinoff, Dan S. Tawfik Proceedings of the National Academy of Sciences May 2021, 118 (21) e2020885118; DOI: 10.1073/pnas.2020885118
The paper is open access.
A friend writes to draw our attention to this sentence: “Life met this challenge by evolving molecular chaperones that can minimize protein misfolding and aggregation, even under stressful out-of-equilibrium conditions favoring aggregation.”
“Life” is a busy little bee, no? If this were not evolutionary biology, we would talk in terms of purpose and design. Oh but, whoops, they do talk in terms of purpose and design. But none dare call it that.