OXSR1 is a member of the neuronal calcium sensor gene family, which encode calcium-binding proteins expressed predominantly in neurons. This protein regulates G protein-coupled receptor phosphorylation in a calcium-dependent manner and can substitute for calmodulin. It is associated with secretory granules and modulates synaptic transmission and synaptic plasticity. Multiple transcript variants encoding different isoforms have been found for this gene. Recombinant human OXSR1 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.