Avtor/Urednik		Petrič, Metka; Vidović, Anja; Dolinar, Klemen; Miš, Katarina; Chibalin, Alexander V.; Pirkmajer, Sergej
Naslov		Phosphorylation of Na+,K+-ATPase at Tyr10 of the [alpha]1-subunit is suppressed by AMPK and enhanced by ouabain in cultured kidney cells
Tip		članek
Leto izdaje		2021
Obseg		str. str.
ISSN		0022-2631 - The Journal of Membrane Biology
Jezik		eng
Abstrakt		Na+,K+-ATPase (NKA) is essential for maintenance of cellular and whole-body water and ion homeostasis. In the kidney, a major site of ion transport, NKA consumes ~ 50% of ATP, indicating a tight coordination of NKA and energy metabolism. AMP-activated protein kinase (AMPK), a cellular energy sensor, regulates NKA by modulating serine phosphorylation of the [alpha]1-subunit, but whether it modulates other important regulatory phosphosites, such as Tyr10, is unknown. Using human kidney (HK-2) cells, we determined that the phosphorylation of Tyr10 was stimulated by the epidermal growth factor (EGF), which was opposed by inhibitors of Src kinases (PP2), tyrosine kinases (genistein), and EGF receptor (EGFR, gefitinib). AMPK activators AICAR and A-769662 suppressed the EGF-stimulated phosphorylation of EGFR (Tyr1173) and NKA[alpha]1 at Tyr10. The phosphorylation of Src (Tyr416) was unaltered by AICAR and increased by A-769662. Conversely, ouabain (100 nM), a pharmacological NKA inhibitor and a putative adrenocortical hormone, enhanced the EGF-stimulated Tyr10 phosphorylation without altering the phosphorylation of EGFR (Tyr1173) or Src (Tyr416). Ouabain (100-1000 nM) increased the ADP:ATP ratio, while it suppressed the lactate production and the oxygen consumption rate in a dose-dependent manner. Treatment with ouabain or gene silencing of NKA[alpha]1 or NKA[alpha]3 subunit did not activate AMPK. In summary, AMPK activators and ouabain had antagonistic effects on the phosphorylation of NKA[alpha]1 at Tyr10 in cultured HK-2 cells, which implicates a role for Tyr10 in coordinated regulation of NKA-mediated ion transport and energy metabolism.
Proste vsebinske oznake		AMPK celice HK-2 K+-ATPaza AMPK HK-2 cells K+-ATPase