mRNA expression of the four isoforms of the human plasma membrane Ca(2+)-ATPase in the human hippocampus

Ca2+ dyshomeostasis is a contributing factor to the development and progression of neurodegenerative disease. Plasma membrane Ca(2+)-ATPases (PMCAs) are responsible for setting intracellular Ca2+ levels and may be involved in the dynamic processing of Ca2+ loads in normal and pathological conditions. In situ hybridization was employed to determine the expression pattern of the four human PMCA isoforms in the human hippocampus. PMCA1 and 3 mRNAs were weakly expressed throughout the hippocampal formation, whereas PMCA2 and 4 mRNA expression showed distinct regional differences, with increased levels in CA2 and the dentate gyrus. Differential expression of PMCA isoforms may reflect cellular differences in Ca(2+)-handling properties and provide a partial explanation for the differential susceptibility of hippocampal neurons to Ca(2+)-mediated cell death.