Response to Comment on "Ancient origins of allosteric activation in a Ser-Thr kinase"

Park et al. question one out of seven findings from Hadzipasic et al.: whether TPX2 allosterically regulates the oldest Aurora. We had already addressed the two concerns raised--sparse sequence sampling and not forcing the gene to the species tree--before publication. Moreover, we believe their ancestral sequence reconstruction would be consistent with a nonallosteric common ancestor, and we show large sequence differences caused by species tree–enforced gene trees. The key findings in Hadzipasic et al. (1) are that (i) autophosphorylation is the ancient allosteric regulation for Aurora kinases; (ii) a gradual increase in allosteric activation took place during the holozoan evolution; (iii) an allosteric network in Aurora exists that, when mutated, alters allosteric activity; (iv) allosteric activation by TPX2 is entirely encoded in the kinase; (v) the interface between Aurora and TPX2 is co-conserved; (vi) evolution of specificity in signaling happens on binding affinity; and (vii) the oldest ancestral Aurora is not allosterically activated by TPX2. Notably, even though the ASR calculations differ, we believe the outcome is consistent with, rather than contradicting, the finding. The two concerns raised are (i) the small number of modern sequences used in the ASR calculations and (ii) the mismatch between the gene tree and the species tree.