N-copine: a novel two C2-domain-containing protein with neuronal activity-regulated expression

Neuronal activity is often associated with changes in gene expression. By a two-dimensional cDNA-display system, restriction landmark cDNA scanning, we identified a novel gene whose expression in the hippocampus was up-regulated by kainate stimulation. The mRNA expression was detected only in brain and up-regulated by the stimulation evoking CA3-CA1 long-term potentiation. The encoded protein contains two copies of C2-domain, known as the Ca2+-binding domain of PKC-gamma, and shows 49% identity with human copine I. We designated this protein N-copine (neuronal-copine). N-copine may have a role in synaptic plasticity.