Regulation of OSR1 and the sodium, potassium, two chloride cotransporter by convergent signals

Samarpita Sengupta, Andres Lorente-Rodriguez, Svetlana Earnest, Steve Stippec, Xiaofeng Guo, David C. Trudgian, Hamid Mirzaei, Melanie H. Cobb

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


The Ste20 family protein kinases oxidative stress-responsive 1 (OSR1) and the STE20/SPS1-related proline-, alanine-rich kinase directly regulate the solute carrier 12 family of cation-chloride cotransporters and thereby modulate a range of processes including cell volume homeostasis, blood pressure, hearing, and kidney function. OSR1 and STE20/SPS1-related proline-, alanine-rich kinase are activated by with no lysine [K] protein kinases that phosphorylate the essential activation loop regulatory site on these kinases. We found that inhibition of phosphoinositide 3-kinase (PI3K) reduced OSR1 activation by osmotic stress. Inhibition of the PI3K target pathway, the mammalian target of rapamycin complex 2 (mTORC2), by depletion of Sin1, one of its components, decreased activation of OSR1 by sorbitol and reduced activity of the OSR1 substrate, the sodium, potassium, two chloride cotransporter, in HeLa cells. OSR1 activity was also reduced with a pharmacological inhibitor of mTOR. mTORC2 phosphorylated OSR1 on S339 in vitro, and mutation of this residue eliminated OSR1 phosphorylation by mTORC2. Thus, we identify a previously unrecognized connection of the PI3K pathway through mTORC2 to a Ste20 protein kinase and ion homeostasis.

Original languageEnglish (US)
Pages (from-to)18826-18831
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number47
StatePublished - Nov 19 2013

ASJC Scopus subject areas

  • General


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