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- Title
Low potassium activation of proximal mTOR/AKT signaling is mediated by Kir4.2.
- Authors
Zhang, Yahua; Bock, Fabian; Ferdaus, Mohammed; Arroyo, Juan Pablo; L Rose, Kristie; Patel, Purvi; Denton, Jerod S.; Delpire, Eric; Weinstein, Alan M.; Zhang, Ming-Zhi; Harris, Raymond C.; Terker, Andrew S.
- Abstract
The renal epithelium is sensitive to changes in blood potassium (K+). We identify the basolateral K+ channel, Kir4.2, as a mediator of the proximal tubule response to K+ deficiency. Mice lacking Kir4.2 have a compensated baseline phenotype whereby they increase their distal transport burden to maintain homeostasis. Upon dietary K+ depletion, knockout animals decompensate as evidenced by increased urinary K+ excretion and development of a proximal renal tubular acidosis. Potassium wasting is not proximal in origin but is caused by higher ENaC activity and depends upon increased distal sodium delivery. Three-dimensional imaging reveals Kir4.2 knockouts fail to undergo proximal tubule expansion, while the distal convoluted tubule response is exaggerated. AKT signaling mediates the dietary K+ response, which is blunted in Kir4.2 knockouts. Lastly, we demonstrate in isolated tubules that AKT phosphorylation in response to low K+ depends upon mTORC2 activation by secondary changes in Cl- transport. Data support a proximal role for cell Cl- which, as it does along the distal nephron, responds to K+ changes to activate kinase signaling. The renal epithelium is sensitive to changes in blood K+. Here, Zhang et al. identify low K+ as a potent activator of proximal tubule mTOR/AKT signaling, which occurs through the K+ channel, Kir4.2 to modulate epithelial cell growth and Na+ transport.
- Subjects
PROXIMAL kidney tubules; POTASSIUM channels; POTASSIUM; THREE-dimensional imaging; SIGNALS &; signaling; EPITHELIAL cells; CELL growth
- Publication
Nature Communications, 2024, Vol 15, Issue 1, p1
- ISSN
2041-1723
- Publication type
Article
- DOI
10.1038/s41467-024-49562-w