title: Src Family Kinase Links Insulin Signaling to Short Term Regulation of Na,K-ATPase in Nonpigmented Ciliary Epithelium.
abstract: Insulin has been shown to elicit changes of Na,K-ATPase activity in various tissues. Na,K-ATPase in the nonpigmented ciliary epithelium (NPE) plays a role in aqueous humor secretion and changes of Na,K-ATPase activity impact the driving force. Because we detect a change of NPE Na,K-ATPase activity in response to insulin, studies were carried out to examine the response mechanism. Ouabain-sensitive rubidium (Rb) uptake by cultured NPE cells, measured as a functional index of Na,K-ATPase-mediated inward potassium transport, was found to increase in cells exposed for 5 min to insulin. The maximally effective concentration was 100 nM. An intrinsic increase of Na,K-ATPase activity evident as a >2-fold increase in the rate of ouabain-sensitive ATP hydrolysis in homogenates obtained from cells exposed to 100 nM insulin for 5 min was also observed. Insulin-treated cells exhibited Akt, Src family kinase (SFK), ERK1/2, and p38 activation, all of which were prevented by a pI3 kinase inhibitor LY294002. The Rb uptake and Na,K-ATPase activity response to insulin both were abolished by PP2, an SFK inhibitor which also prevented p38 and ERK1/2 but not Akt activation. The Akt inhibitor MK-2206 did not change the Na,K-ATPase response to insulin. The findings suggest insulin activates pI3K-dependent Akt and SFK signaling pathways that are separate. ERK1/2 and p38 activation is secondary to and dependent on SFK activation. The increase of Na,K-ATPase activity is dependent on activation of the SFK pathway. The findings are consistent with previous studies that indicate a link between Na,K-ATPase activity and SFK signaling. J. Cell. Physiol. 232: 1489-1500, 2017. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Physiology and Ophthalmology and Vision Science, University of Arizona, Tucson, Arizona.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Shahidullah
authors.affiliation: Department of Physiology and Ophthalmology and Vision Science, University of Arizona, Tucson, Arizona.
authors.forename: Amritlal
authors.initials: A
authors.lastname: Mandal
authors.affiliation: Department of Physiology and Ophthalmology and Vision Science, University of Arizona, Tucson, Arizona.
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Delamere
mesh_terms: D000818:Animals; D002070:Butadienes / Q000494:pharmacology; D002867:Chromones / Q000494:pharmacology; D002924:Ciliary Body / Q000187:drug effects / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006575:Heterocyclic Compounds, 3-Ring / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D007328:Insulin / Q000378:metabolism* / Q000494:pharmacology; D008954:Models, Biological; D009025:Morpholines / Q000494:pharmacology; D009570:Nitriles / Q000494:pharmacology; D010042:Ouabain / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation / Q000187:drug effects; D010858:Pigmentation / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011725:Pyridines / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D012413:Rubidium / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D034421:Sus scrofa; D013997:Time Factors; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism; D019061:src-Family Kinases / Q000378:metabolism*
chemical_list: D002070:Butadienes; D002867:Chromones; D048049:Extracellular Signal-Regulated MAP Kinases; D006575:Heterocyclic Compounds, 3-Ring; D007093:Imidazoles; D007328:Insulin; D009025:Morpholines; D009570:Nitriles; D010042:Ouabain; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt; D011725:Pyridines; D011743:Pyrimidines; D012413:Rubidium; D000254:Sodium-Potassium-Exchanging ATPase; D048051:p38 Mitogen-Activated Protein Kinases; D019061:src-Family Kinases; C412373:AG 1879; C548887:MK 2206; C113580:U 0126; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C090942:4-(4-fluorophenyl)-2-(4-hydroxyphenyl)-5-(4-pyridyl)imidazole