Distribution and intracellular localization of a mouse homologue of Ca2+/calmodulin-dependent protein kinase Ibeta2 in the nervous system.

Ca 2+ /calmodulin-dependent protein kinases (CaMKs) are believed to play important roles in the development and function of the nervous system. We report here the identification and expression of mouse CaMKIβ (mCaMKIβ), in particular mCaMKIβ2, an isoform of mCaMKIβ. During embryogenesis, the mCaMKIβ2 gene is expressed mainly in the nervous system, including brain, spinal cord, trigeminal ganglion, and retina. Within the CNS, the expression of mCaMKIβ2 is detected in the mantle zone, but not in the ventricular zone, suggesting its possible involvement in the differentiation of neurons. In the adult brain, mCaMKIβ2 transcripts are detected at high levels in the anterior olfactory nuclei, piriform cortex, septal nuclei, bed nuclei of the stria terminalis, hippocampal pyramidal cells, dentate granule cells, amygdala, hypothalamic nuclei, parabrachial nucleus, and nucleus of the solitary tract. The distinct gene expression pattern suggests that mCaMKIβ2 may also be involved in different mature neuronal functions from other CaMKs. In addition, mCaMKIβ2 proteins are localized to the cytoplasm and nuclei, but not to nucleoli, suggesting that mCaMKIβ2 proteins might be involved in the cytoplasmic and nuclear signal transduction of the nervous system.