کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1956810 1057868 2005 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Epithelial Na+ Channel Subunit Stoichiometry
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شیمی
پیش نمایش صفحه اول مقاله
Epithelial Na+ Channel Subunit Stoichiometry
چکیده انگلیسی

Ion channels, including the epithelial Na+ channel (ENaC), are intrinsic membrane proteins comprised of component subunits. Proper subunit assembly and stoichiometry are essential for normal physiological function of the channel protein. ENaC comprises three subunits, α, β, and γ, that have common tertiary structures and much amino acid sequence identity. For maximal ENaC activity, each subunit is required. The subunit stoichiometry of functional ENaC within the membrane remains uncertain. We combined a biophysical approach, fluorescence intensity ratio analysis, used to assess relative subunit stoichiometry with total internal reflection fluorescence microscopy, which enables isolation of plasma membrane fluorescence signals, to determine the limiting subunit stoichiometry of ENaC within the plasma membrane. Our results demonstrate that membrane ENaC contains equal numbers of each type of subunit and that at steady state, subunit stoichiometry is fixed. Moreover, we find that when all three ENaC subunits are coexpressed, heteromeric channel formation is favored over homomeric channels. Electrophysiological results testing effects of ENaC subunit dose on channel activity were consistent with total internal reflection fluorescence/fluorescence intensity ratio findings and confirmed preferential formation of heteromeric channels containing equal numbers of each subunit.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: - Volume 88, Issue 6, June 2005, Pages 3966–3975
نویسندگان
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