Calretinin also known as CR, calbindin 2, CALB2 is an intracellular calcium-binding protein belonging to the troponin C superfamily. Calretinin plays a significant role in calcium signaling within neurons. Calretinin′s ability to bind calcium ions is essential for regulating various cellular processes, including neurotransmitter release and neuronal excitability, which are vital for proper brain function and communication between neurons. Calretinin is predominantly expressed in the brain, particularly in auditory neurons, where Calretinin contributes to the precise timing of neuronal discharges. Additionally, Calretinin-immunoreactive boutons form both asymmetrical and symmetrical synaptic specializations on spines, dendrites, and somata, highlighting Calretinin′s importance in synaptic plasticity and neuronal connectivity.