Identification of a Major Determinant for Serine-Threonine Kinase Phosphoacceptor Specificity

Journal article

Eukaryotic protein kinases are generally classified as being either tyrosine or serine-threonine specific. Though not evident from inspection of their primary sequences, many serine-threonine kinases display a significant preference for serine or threonine as the phosphoacceptor residue. Here we show that a residue located in the kinase activation segment, which we term the "DFG+1" residue, acts as a major determinant for serine-threonine phosphorylation site specificity. Mutation of this residue was sufficient to switch the phosphorylation site preference for multiple kinases, including the serine-specific kinase PAK4 and the threonine-specific kinase MST4. Kinetic analysis of peptide substrate phosphorylation and crystal structures of PAK4-peptide complexes suggested that phosphoacceptor residue preference is not mediated by stronger binding of the favored substrate. Rather, favored kinase-phosphoacceptor combinations likely promote a conformation optimal for catalysis. Understanding the rules governing kinase phosphoacceptor preference allows kinases to be classified as serine or threonine specific based on their sequence. © 2014 The Authors.

Authors: Chen, C; Ha, B; Thévenin, A; Lou, H; Zhang, R

• Journal: Molecular Cell
• Volume: 53
• Issue: 1
• Pages: 140-147
• Publication date: 2014-01-09
• DOI: 10.1016/j.molcel.2013.11.013
• EISSN: 1097-4164
• ISSN: 1097-2765