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Mutations in the finger domain of the epithelial sodium channel alter the shear stress response
Author(s) -
Shi Shujie,
Kashlan Ossama B.,
Carattino Marcelo D.,
Kleyman Thomas R.
Publication year - 2011
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.25.1_supplement.1041.11
Subject(s) - epithelial sodium channel , extracellular , biophysics , chemistry , shear stress , sodium channel , ion channel , allosteric regulation , patch clamp , microbiology and biotechnology , sodium , biology , biochemistry , enzyme , materials science , receptor , organic chemistry , composite material
The epithelial sodium channel (ENaC) is regulated by multiple extracellular stimuli, including shear stress. Previous studies suggest that the extracellular finger domains of ENaC α and γ subunits contain allosteric regulatory modules. However, the role of the finger domain in the shear stress response is unknown. Tryptophan scanning mutagenesis was employed to identify key residues within the tract αK250 to αL290 in the finger domain of the ENaCα that affect the response of channels to shear stress. Functional activity was studied with the two‐electrode voltage clamp technique. Substitutions at positions Y265, Q266, S269, V272, A274, R276, Y279, F281, I284, and I286 altered the magnitude of channel activation by shear stress. The kinetic of channel activation was altered when bulky tryptophan residues were introduced at positions L255, C256, S270 and G271. Our results suggest that a 32 amino acid tract (αL255 to αI286) modulates the response of ENaC to shear stress, and are consistent with the hypothesis that external signals trigger movements within the extracellular regions of ENaC subunits that are transmitted to the channel pore. (Supported by AHA postdoctoral fellowship, R01 DK051391, R01 DK054354, P30 DK079307)