Constraints on the evolution of toxin-resistant Na,K-ATPases have limited dependence on sequence divergence

Shabnam Mohammadi, Santiago Herrera-Álvarez, Lu Yang, María del Pilar Rodríguez-Ordoñez, Karen Zhang, Jay F. Storz, Susanne Dobler, Andrew J. Crawford, Peter Andolfatto

Research output: Contribution to journalArticlepeer-review

Abstract

A growing body of theoretical and experimental evidence suggests that intramolecular epistasis is a major determinant of rates and patterns of protein evolution and imposes a substantial constraint on the evolution of novel protein functions. Here, we examine the role of intramolecular epistasis in the recurrent evolution of resistance to cardiotonic steroids (CTS) across tetrapods, which occurs via specific amino acid substitutions to the α-subunit family of Na,K-ATPases (ATP1A). After identifying a series of recurrent substitutions at two key sites of ATP1A that are predicted to confer CTS resistance in diverse tetrapods, we then performed protein engineering experiments to test the functional consequences of introducing these substitutions onto divergent species backgrounds. In line with previous results, we find that substitutions at these sites can have substantial background-dependent effects on CTS resistance. Globally, however, these substitutions also have pleiotropic effects that are consistent with additive rather than background-dependent effects. Moreover, the magnitude of a substitution’s effect on activity does not depend on the overall extent of ATP1A sequence divergence between species. Our results suggest that epistatic constraints on the evolution of CTS-resistant forms of Na,K-ATPase likely depend on a small number of sites, with little dependence on overall levels of protein divergence. We propose that dependence on a limited number sites may account for the observation of convergent CTS resistance substitutions observed among taxa with highly divergent Na,K-ATPases (See S1 Text for Spanish translation).

Original languageEnglish (US)
Article numbere1010323
JournalPLoS genetics
Volume18
Issue number8
DOIs
StatePublished - Aug 16 2022
Externally publishedYes

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Molecular Biology
  • Genetics
  • Genetics(clinical)
  • Cancer Research

Fingerprint

Dive into the research topics of 'Constraints on the evolution of toxin-resistant Na,K-ATPases have limited dependence on sequence divergence'. Together they form a unique fingerprint.

Cite this