Protein kinases have evolved diverse specificities to enable cellular information processing. To gain insight into the mechanisms underlying kinase diversification, we studied the CMGC protein kinases using ancestral reconstruction. Within this group, the cyclin dependent kinases (CDKs) and mitogen activated protein kinases (MAPKs), require proline at the +1 position of their substrates, while Ime2 prefers arginine. The resurrected common ancestor of CDKs, MAPKs and Ime2 could phosphorylate substrates with +1 proline or arginine, with preference for proline. This specificity changed to a strong preference for +1 arginine in the lineage leading to Ime2 via an intermediate with equal specificity for proline and arginine. Mutant analysis revealed that a variable residue within the kinase catalytic cleft, DFGx, modulates +1 specificity. Expansion of Ime2 kinase specificity by mutation of this residue did not cause dominant deleterious effects in vivo. Tolerance of cells to new specificities likely enabled the evolutionary divergence of kinases.
- James Ferrell, Stanford University, United States
- Received: July 23, 2014
- Accepted: October 9, 2014
- Accepted Manuscript published: October 13, 2014 (version 1)
- Accepted Manuscript updated: October 14, 2014 (version 2)
- Version of Record published: November 12, 2014 (version 3)
- Version of Record updated: April 29, 2016 (version 4)
- Version of Record updated: August 5, 2016 (version 5)
© 2014, Howard et al.
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