| Autor: |
Cairo ER; Department of Biochemistry, Radboud University Nijmegen Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands., Swarts HG, Wilmer MJ, Willems PH, Levtchenko EN, De Pont JJ, Koenderink JB |
| Jazyk: |
angličtina |
| Zdroj: |
The Journal of membrane biology [J Membr Biol] 2009 Oct; Vol. 231 (2-3), pp. 117-24. Date of Electronic Publication: 2009 Oct 29. |
| DOI: |
10.1007/s00232-009-9210-4 |
| Abstrakt: |
Autosomal dominant renal hypomagnesemia (OMIM 154020), associated with hypocalciuria, has been linked to a 121G to A mutation in the FXYD2 gene. To gain insight into the molecular mechanisms linking this mutation to the clinical phenotype, we studied isolated proximal tubular cells from urine of a patient and a healthy subject. Cells were immortalized and used to assess the effects of hypertonicity-induced overexpression of FXYD2 on amount, activity and apparent affinities for Na(+), K(+) and ATP of Na,K-ATPase. Both cell lines expressed mRNA for FXYD2a and FXYD2b, and patient cells contained both the wild-type and mutated codons. FXYD2 protein expression was lower in patient cells and could be increased in both cell lines upon culturing in hyperosmotic medium but to a lesser extent in patient cells. Similarly, hyperosmotic culturing increased Na,K-ATPase protein expression and ATP hydrolyzing activity but, again, to a lesser extent in patient cells. Apparent affinities of Na,K-ATPase for Na(+), K(+) and ATP did not differ between patient and control cells or after hyperosmotic induction. We conclude that human proximal tubular cells respond to a hyperosmotic challenge with an increase in FXYD2 and Na,K-ATPase protein expression, though to a smaller absolute extent in patient cells. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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