Structural Basis of Inward Rectification: Cytoplasmic Pore of the G Protein-Gated Inward Rectifier GIRK1 at 1.8 A Resolution
Nishida, M., MacKinnon, R.(2002) Cell 111: 957-965
- PubMed: 12507423 
- DOI: https://doi.org/10.1016/s0092-8674(02)01227-8
- Primary Citation of Related Structures:  
1N9P - PubMed Abstract: 
Inward rectifier K(+) channels govern the resting membrane voltage in many cells. Regulation of these ion channels via G protein-coupled receptor signaling underlies the control of heart rate and the actions of neurotransmitters in the central nervous system. We have determined the protein structure formed by the intracellular N- and C termini of the G protein-gated inward rectifier K(+) channel GIRK1 at 1.8 A resolution. A cytoplasmic pore, conserved among inward rectifier K(+) channels, extends the ion pathway to 60 A, nearly twice the length of a canonical transmembrane K(+) channel. The cytoplasmic pore is lined by acidic and hydrophobic amino acids, creating a favorable environment for polyamines, which block the pore. These results explain in structural and chemical terms the basis of inward rectification, and they also have implications for G protein regulation of GIRK channels.
Organizational Affiliation: 
Howard Hughes Medical Institute and Laboratory of Molecular Neurobiology and Biophysics, Rockefeller University, New York, NY 10021, USA.