AMP-activated Protein Kinase Regulates the Vacuolar H+-ATPase via Direct Phosphorylation of the A Subunit (ATP6V1A) in Kidney.

AMP-activated Protein Kinase Regulates the Vacuolar H+-ATPase via Direct Phosphorylation of the A Subunit (ATP6V1A) in Kidney.
Am J Physiol Renal Physiol. 2013 Jul 17;
Authors: Alzamora R, Al-Bataineh MM, Liu W, Gong F, Li H, Thali RF, Joho-Auchli Y, Brunisholz RA, Satlin LM, Neumann D, Hallows KR, Pastor-Soler NM
Abstract
The vacuolar H(+)-ATPase (V-ATPase) in intercalated cells contributes to luminal acidification in the kidney collecting duct and non-volatile acid excretion. We previously showed that the A subunit in the cytoplasmic V1 sector of the V-ATPase (ATP6V1A) is phosphorylated by the metabolic sensor AMP-activated protein kinase (AMPK) in vitro and in kidney cells. Here we demonstrate that treatment of rabbit isolated perfused collecting ducts with the AMPK activator AICAR (5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside) inhibited V-ATPase-dependent H(+) secretion from intercalated cells after an acid load. We have identified by mass spectrometry that Ser-384 is a major AMPK phosphorylation site in the V-ATPase A subunit, a result confirmed by comparing AMPK-dependent phosphate labeling of wild-type A-subunit (WT-A) with that of a Ser-384-to-Ala A subunit mutant (S384A-A) in vitro and in intact HEK-293 cells. As compared with WT-A-expressing HEK-293 cells, S384A-A-expressing cells exhibited greater steady-state acidification of HCO3(-)-containing media. Moreover, AICAR treatment of Clone C rabbit intercalated cells expressing...

Source: Am J Physiol Renal P... - July 17, 2013 Category: Urology & Nephrology Authors: Alzamora R, Al-Bataineh MM, Liu W, Gong F, Li H, Thali RF, Joho-Auchli Y, Brunisholz RA, Satlin LM, Neumann D, Hallows KR, Pastor-Soler NM Tags: Am J Physiol Renal Physiol Source Type: research