Simultaneous loss of CAMK2A and CAMK2B reveals endogenous in vivo substrates

Ca 2+ /calmodulin-dependent protein kinase 2 (CAMK2) plays a critical role in calcium signaling. Recent gene knockout studies show that CAMK2A and CAMK2B can have distinct roles yet also partially compensate for each other in yet unknown brain functions. In order to provide insight into potential novel CAMK2 functions, we performed parallel phosphoproteomic analyses on non-stimulated cortex tissue from inducible Camk2a and Camk2b double knockout ( Camk2a f/f ;Camk2b f/f ;CAG-Cre ESR ) mice and from wild type mice. A total of 5622 phosphorylated peptides derived from 2080 proteins were identified. Phosphorylation at serine/threonine residues in 130 proteins were downregulated in the double knockout mice, including residues in 113 proteins that have not previously been identified as potential CAMK2 substrates. Comparison of amino acid sequences surrounding the downregulated phosphorylation residues provided new insights into the CAMK2-substrate consensus sequences in vivo . This dataset provides an important resource for future studies examining novel roles for CAMK2 in the brain.