Although multiple phosphorylation sites are often clustered in substrates, the mechanism of phosphorylation within clusters has not been systematically investigated. Intriguingly, in addition to acidic residues, protein kinase CK2 can use phosphoserine residues as consensus determinants suggesting that CK2 may act in concert with other kinases. We used a peptide array approach to outline optimal consensus sequences for hierarchical phosphorylation by CK2, both in the context of processive, multisite phosphorylation, and in concert with a priming proline-directed kinase. Results suggest that hierarchical phosphorylation involving CK2 requires precise positioning of either multiple phosphodeterminant residues or specific combinations of canonical determinants and phosphodeterminants, and can be as enzymatically favorable as canonical CK2 phosphorylation. Over 1600 human proteins contain at least one CK2 hierarchical consensus motif, and ~20

作者：Nicole, St-Denis；Michelle, Gabriel；Jacob P, Turowec；Gregory B, Gloor；Shawn S-C, Li；Anne-Claude, Gingras；David W, Litchfield

来源：Journal of proteomics 2015 年 118卷