Permanent URL to this publication: http://dx.doi.org/10.5167/uzh-48252
Föller, M; Kempe, D S; Boini, K M; Pathare, G; Siraskar, B; Capuano, P; Alesutan, I; Sopjani, M; Stange, G; Mohebbi, N; Bhandaru, M; Ackermann, T F; Judenhofer, M S; Pichler, B J; Biber, J; Wagner, C A; Lang, F (2011). PKB/SGK-resistant GSK3 enhances phosphaturia and calciuria. Journal of the American Society of Nephrology (JASN), 22(5):873-880.
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Insulin and IGF1-dependent signaling activates protein kinase B and serum and glucocorticoid inducible kinase (PKB/SGK), which together phosphorylate and inactivate glycogen synthase kinase GSK3. Because insulin and IGF1 increase renal tubular calcium and phosphorus reabsorption, we examined GSK3 regulation of phosphate transporter activity and determined whether PKB/SGK inactivates GSK3 to enhance renal phosphate and calcium transport. Overexpression of GSK3 and the phosphate transporter NaPi-IIa in Xenopus oocytes decreased electrogenic phosphate transport compared with NaPi-IIa-expressing oocytes. PKB/SGK serine phosphorylation sites in GSK3 were mutated to alanine to create gsk3(KI) mice resistant to PKB/SGK inactivation. Compared with wildtype animals, gsk3(KI) animals exhibited greater urinary phosphate and calcium clearances with higher excretion rates and lower plasma concentrations. Isolated brush border membranes from gsk3(KI) mice showed less sodium-dependent phosphate transport and Na-phosphate co-transporter expression. Parathyroid hormone, 1,25-OH vitamin D levels, and bone mineral density were decreased in gsk3(KI) mice, suggesting a global dysregulation of bone mineral metabolism. Taken together, PKB/SGK phosphorylation of GSK3 increases phosphate transporter activity and reduces renal calcium and phosphate loss.
|Item Type:||Journal Article, refereed, original work|
|Communities & Collections:||04 Faculty of Medicine > Institute of Physiology|
07 Faculty of Science > Institute of Physiology
04 Faculty of Medicine > Center for Integrative Human Physiology
|DDC:||570 Life sciences; biology|
610 Medicine & health
|Deposited On:||06 Jun 2011 15:00|
|Last Modified:||23 Nov 2012 15:02|
|Publisher:||American Society of Nephrology|
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