Calretinin also known as 29 kDa calbindin is a calcium-binding protein involved in calcium signaling. Calretinin is an intracellular calcium-binding protein belonging to the troponin C superfamily. Members of this protein family have six EF-hand domains which bind calcium. This protein plays a role in diverse cellular functions, including message targeting and intracellular calcium buffering. Calretinin has an important role as a modulator of neuronal excitability including the induction of long-term potentiation.