Order, disorder, and phosphorylation
Phosphorylation selection. As protein kinases evolved and species complexity increased, the numbers of genomically encoded tyrosine residues [and thus phosphorylated tyrosines (pY)] decreased proportionally. This negative correlation also applies to threonine (pT) but not serine (pS) residues. Positionally conserved phosphorylation sites tend to be located in ordered protein domains, whereas those not conserved are located in intrinsically disordered regions where their exact positions shift with evolutionary time.
via sciencemag.org
