Key result
Conservative I470 mutations in Shaker potassium channels modify C-type inactivation rates at the outer pore.
Why the study?
Functional coupling mechanisms between the inner activation gate and outer pore gates in potassium channels remain to be elucidated at the residue and structural pathway level.
The I470 residue in the Shaker potassium channel is a critical component of the allosteric pathway coupling inner gate opening to outer pore C-type inactivation.
Answers are grounded in this paper and cite their sources.
Residue near inner gate influences outer inactivation; extends Kv channel coupling models but leaves clinical translation open.
In potassium channels, functional coupling of the inner and outer pore gates may result from energetic interactions between residues and conformational rearrangements that occur along a structural path between them. Here, we show that conservative mutations of a residue near the inner activation gate of the Shaker potassium channel (I470) modify the rate of C-type inactivation at the outer pore, pointing to this residue as part of a pathway that couples inner gate opening to changes in outer pore structure and reduction of ion flow. Because they remain equally sensitive to rises in extracellular potassium, altered inactivation rates of the mutant channels are not secondary to modified binding of potassium to the outer pore. Conservative mutations of I470 also influence the interaction of the Shaker N-terminus with the inner gate, which separately affects the outer pore.
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Peters et al. (2013) studied Potassium channel gating (Basic Science). I470 mutations in Shaker potassium channel vs. Wild-type Shaker channel was evaluated on Rate of C-type inactivation. Conservative mutations of the I470 residue near the inner activation gate of the Shaker potassium channel modify the rate of C-type inactivation at the outer pore.
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