In the absence of calcium (Ca2+), calmodulin (CALM1) binds to neurogranin (NRGN) (Seeger et al. 2017). NRGN is enriched in dendritic spines where it slows down the diffusion rate of CALM1. NRGN increases the local concentration of CALM1 and enhances Ca2+ sensitivity at the synapse, thereby enhancing synaptic strength. The association between NRGN and CALM1 is dynamic, and NRGN does not sequester CALM1 (Petersen and Gerges 2015). Nrgn knockout mice exhibit impaired synaptic plasticity and spatial learning, with reduced ability to generate activated CaMKII after stimulation (Pak et al. 2000).