engleski

Na, K-ATPase beta3 subunit gene expression is altered in brain tissue of ganglioside deficient mice

Na, K-ATPase, or sodium pump, maintains steep electrochemical gradients across cell membranes. This pump is an oligomer consisting of alpha and beta subunits ; alpha being the catalytic subunit, while beta is required for biogenesis and correct folding of the alpha subunit in the membrane. Beta subunit has also been shown to have a role in cell-cell adhesion, however all potential partners interacting with this subunit have not yet been identified. It has been previously demonstrated that certain gangliosides, sialic acid-bearing membrane glycosphingolipids especially abundant in brain tissue, activate Na, K-ATPase. The aim of this study was to examine whether changed ganglioside composition of the cell has an effect on Na, K-ATPase beta3 subunit (Atp1b3) gene expression. We used cerebellar and hippocampal tissue of two ganglioside deficient knockout mouse models, St8sia1 and B4galnt1, whose phenotypes include impaired peripheral nerve regeneration, dysmyelination, axonal degeneration, impaired motor coordination and hyperactivity. We performed quantitative real-time PCR and compared relative gene expression levels for Atp1b3 in both tissues for the two mouse models in comparison to wild-type mice. We found that in St8sia1 model gene expression of Atp1b3 was downregulated for cerebellum and hippocampus. Interestingly, in B4galnt1 mice the expression for the same gene was upregulated in both tissues. We suggest that specific ganglioside membrane composition probably affects Na, K-ATPase beta subunit expression which could lead to changes in assembly of the whole pump resulting in decrease or increase of its catalytic activity. This assumption needs confirmation by measuring Na, K-ATPase enzymatic activity in brain tissue of ganglioside deficient mice.

Na; K-ATPase; brain gangliosides; ganglioside deficient mice

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