Leucine-rich repeat neuronal protein 3, also known as neuronal leucine-rich repeat protein 3 (NLRR-3), is a member of the leucine-rich (LRR) family whose members have significant functions in neural development. Leucine-rich repeats are short sequence motifs present in some proteins with diverse functions and cellular locations. All proteins containing these repeats are thought to be involved in protein-protein interactions. The crystal structure of ribonuclease inhibitor protein has revealed that leucine-rich repeats correspond to β-α structural units. These units are arranged so that they form a parallel β-sheet with one surface exposed to solvent so that the protein acquires an unusual, non-globular shape. These two features may be responsible for the protein-binding functions of proteins containing leucine-rich repeats. LRRN3 plays an important role in cerebellum postnatal development. In a unilateral cortical injury cerebral cortex, NLRR-3 mRNA increased in layers 2-3 which suggests that NLRR-3 may be an important component of the pathophysiological response to brain injury.