Neurons and astroglia express distinct subsets of Na,K-ATPase alpha and beta subunits.
We have analyzed the expression pattern of Na,K-ATPase alpha and beta subunit isoforms within the rodent and primate central nervous system. Membrane fractions prepared from rat cerebral cortical type-1 astrocytes and rat cerebellar granule and hippocampal neurons were characterized by immunoblot analyses using a panel of alpha and beta subunit isoform-specific antisera. Each cell type was found to express the alpha 1 isoform but showed differences in the expression of other subunits. Cortical astrocytes displayed alpha 2 and beta 2 subunits, whereas cerebellar granule neurons showed expression of alpha 3 and beta 1 subunits. All three alpha subunit isotypes were detected in hippocampal neurons. A survey of the immunofluorescent staining pattern of the alpha 3 subunit in rat and monkey brain confirmed that expression of this Na,K-ATPase alpha subunit isoform was restricted exclusively to neurons. These results suggest that both neurons and astrocytes express multiple, yet distinct, Na,K-ATPase isoenzymes. The identification of cell types expressing limited combinations of alpha and beta subunits should provide a framework for understanding the physiological significance of Na,K-ATPase isoenzyme diversity and may provide useful tools for the analysis of cell lineage in the mammalian central nervous system.
Cameron
R
R
Section of Neurobiology, Yale University School of Medicine, New Haven, CT 06510.
Klein
L
L
Shyjan
A W
AW
Rakic
P
P
Levenson
R
R
D000818:Animals; D001253:Astrocytes / Q000201:enzymology*; D015415:Biomarkers / Q000737:chemistry; D001921:Brain / Q000166:cytology / Q000201:enzymology*; D015151:Immunoblotting; D017403:In Situ Hybridization; D007527:Isoenzymes / Q000032:analysis*; D008253:Macaca mulatta; D008856:Microscopy, Fluorescence; D009474:Neurons / Q000201:enzymology*; D051381:Rats; D000254:Sodium-Potassium-Exchanging ATPase / Q000032:analysis*
D015415:Biomarkers; D007527:Isoenzymes; D000254:Sodium-Potassium-Exchanging ATPase