A Conserved Arginine Residue in the Pore Region of an Inward Rectifier K Channel (IRK1) as an External Barrier for Cationic Blockers

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Population

Inward rectifier K channel (IRK1/Kir2.1) model

Comparison

Mutation of Arg148 to His and coexpression with… vs Wild-type IRK1 channels

Design

Preclinical

Authors

Discussion

R148H alters Kir2.1 blocker access in oocytes; extends channel biophysics but leaves open any role in human arrhythmias.

Population

Inward rectifier K channel (IRK1/Kir2.1) model

Intervention

Mutation of Arg148 to His (R148H) and coexpression with wild-type mRNA

Comparator

Wild-type IRK1 channels

Outcome

Channel activity, single-channel conductance, and sensitivity to extracellular block by Mg2+, Ca2+, Cs+, and Ba2+surrogate

Arg148 in the IRK1 channel serves as a critical external barrier to cationic blockers, keeping Mg2+ and Ca2+ out of the membrane's electric field.

Sabirov et al. (1997) studied this question.

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