Neuronal calcium sensor, regulator of G protein-coupled receptor phosphorylation in a calcium dependent manner. Directly regulates GRK1 (RHOK), but not GRK2 to GRK5. Can substitute for calmodulin (By similarity). Stimulates PI4KB kinase activity (By similarity). Involved in long-term synaptic plasticity through its interaction with PICK1 (By similarity). May also play a role in neuron differentiation through inhibition of the activity of N-type voltage-gated calcium channel (By similarity). Monomer (By similarity). Interacts with KCND2 (By similarity). Interacts in a calcium-independent manner with PI4KB, but only if myristoylated (PubMed:11526106). This binding competes with CALN2/CABP7 binding to PI4KB (PubMed:11526106). Interacts in a calcium-dependent manner with PICK1 (via AH domain) (By similarity). Interacts with ARF1, ARF3, ARF5 and ARF6 (By similarity). Interacts with IL1RAPL1 (By similarity). Associated with Golgi stacks. Post-synaptic densities of dendrites, and in the pre-synaptic nerve terminal at neuromuscular junctions. Binds 3 calcium ions via the second, third and fourth EF-hand. Belongs to the recoverin family.