Premium
Ribosomal S‐6 kinase and Rho‐associated kinase phosphorylation of NHE1
Author(s) -
Dornbusch Andrew,
Berthelsen Nicholas,
Anderson Kristina,
Provost Joseph,
Wallert Mark
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.988.5
Subject(s) - sodium–hydrogen antiporter , phosphorylation , microbiology and biotechnology , intracellular ph , rhoa , kinase , rho associated protein kinase , ribosomal s6 kinase , chemistry , biology , intracellular , sodium , signal transduction , p70 s6 kinase 1 , protein kinase b , organic chemistry
Regulation of the Sodium‐Hydrogen Exchanger isoform‐1 (NHE1) is critical in the control of intracellular pH and cell volume. NHE1 also provides a focal point between the cytoskeleton and the plasma membrane resulting in the coordination of directed cellular migration. Both RhoA Kinase (ROCK) and Ribosomal S‐6 kinase (Rsk) regulate these NHE1 functions, however the site of NHE1 phosphorylated by ROCK and it's specific impact on NHE1 function has not been determined. Using recombinant c‐terminus NHE1 we show site‐specific ROCK phosphorylation of NHE1. To understand the role of both kinases on NHE1 we have created stable cell lines that express full‐length tagged human wild‐type NHE1 with Ser/Thr to Ala mutations. The expression level and location of recombinant NHE1 was assessed by western blot and confocal microscopy. Loss of either NHE1 phosphorylation site altered NHE1 activity following intracellular acidosis. The impact of NHE1 phosphorylation showed that phosphorylation of ROCK and RSK are both critical in formation of stress fibers and migration, however loss of either phosphorylation site poorly impacts proliferation. Our data demonstrates that NHE1 is a substrate for ROCK phosphorylation and that both ROCK and Rsk sites play a critical role in NHE1 function. This work was supported with funds from NSF MCB‐0817784