Regional expression and subcellular localization of the voltage-gated calcium channel β subunits in the developing mouse brain

J. Neurochem. (2012) 122, 10951107. Abstract Ca2+ channel beta subunits determine the maturation, biophysical properties and cell surface expression of high voltage-activated channels. Thus, we have analysed the expression, regional distribution and subcellular localization of the Cav beta subunit family in mice from birth to adulthood. In the hippocampus and cerebellum, Cav beta 1, Cav beta 3 and Cav beta 4 protein levels increased with age, although there were marked region- and developmental stage-specific differences in their expression. Cav beta 1 was predominantly expressed in the strata oriens and radiatum of the hippocampus, and only weakly in the cerebellum. The Cav beta 3 subunit was mainly expressed in the strata radiatum and lucidum of the hippocampus and in the molecular layer of the cerebellum. During development, Cav beta 3 protein expression in the cerebellum peaked at postnatal days (P) 15 and 21, and had diminished drastically by P60, and in the hippocampus increased with age throughout all subfields. Cav beta 4 protein was detected throughout the cerebellum, particularly in the molecular layer, and in contrast to the other subunits, Cav beta 4 was mainly detected in the molecular layer and the hilus of the hippocampus. At the subcellular level, Cav beta 1 and Cav beta 3 were predominantly located post-synaptically in hippocampal pyramidal cells and cerebellar Purkinje cells. Cav beta 4 subunits were detected in the pre-synaptic and post-synaptic compartments of both regions, albeit more strongly at post-synaptic sites. These results shed new light on the developmental regulation and subcellular localization of Cav beta subunits, and their possible role in pre- and post-synaptic transmission.