Neurogranin (NRGN)
Neurogranin is a calmodulin-binding protein expressed exclusively in the brain, particularly in dendritic spines, and participating in the protein kinase C signaling pathway. Neurogranin is the main postsynaptic protein regulating the availability of calmodulin, binding to it in the absence of calcium. Phosphorylation by protein kinase C lowers its binding ability. NRGN gene expression is controlled by thyroid hormones. One study tells of potential link of neurogranin gene to the heightened risk of schizophrenia in males, another study gives evidence of lowered neurogranin immunoreactivity in the brains of people suffering from schizophrenia.Prior to its identification in the bovine and rat brain in 1991, neurogranin was known as a putative protein kinase C-phosphorylated protein named p17.