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NO regulation of Na,K‐ATPase in ocular ciliary epithelium involves Src Family Kinase
Author(s) -
Shahidullah Mohammad,
Mandal Amritlal,
Wei Guojun,
Delamere Nicholas A
Publication year - 2013
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.27.1_supplement.1210.10
Subject(s) - phosphorylation , ouabain , chemistry , kinase , microbiology and biotechnology , src family kinase , protein kinase a , atpase , biochemistry , biology , proto oncogene tyrosine protein kinase src , enzyme , sodium , organic chemistry
The nitric oxide (NO) donor SNP reduces aqueous humor (AH) secretion in the isolated porcine eye. SNP inhibits Na,K‐ATPase activity in AH‐secreting tissue, nonpigmented ciliary epithelium (NPE), through a cGMP/PKG‐mediated pathway. Here we study the role of Src family kinases (SFKs) in the Na,K‐ATPase activity response to NO. NPE was cultured and Na,K‐ATPase activity measured by quantification of ATP hydrolysis in NPE lysate and by estimating ouabain‐sensitive potassium ( 86 Rb) uptake in intact NPE. Protein phosphorylation was examined by western blot. SNP inhibited Na,K‐ATPase activity by >;35% but did not change Ser 16 phosphorylation of the Na,K‐ATPase α1 subunit or the abundance of α1 protein available for surface biotinylation. The SFK inhibitor PP2 prevented both SNP and 8‐Br‐cGMP‐induced reduction of Na,K‐ATPase activity. SNP and 8‐Br‐cGMP increased phosphorylation of SFK, ERK1/2 and p‐38 MAPK. PP2 prevented the responses. The ERK1/2 inhibitor U0126 prevented SNP‐induced ERK1/2 and p‐38 phosphorylation but did not suppress SNP‐induced SFK phosphorylation or Na,K‐ATPase activity reduction. SNP caused detectable phosphorylation of Na,K‐ATPase α1 at Tyr 10 . NO‐induced inhibition of Na,K‐ATPase activity appears to depend on SFK activation that occurs via cGMP/PKG. Funding: NIH Grant EY006915.