3AGW

Crystal Structure of the Cytoplasmic Domain of G-Protein-Gated Inward Rectifier Potassium Channel Kir3.2 in the absence of Na+

Summary for 3AGW

• Entry DOI: 10.2210/pdb3agw/pdb
• Related: 2E4F
• Descriptor: G protein-activated inward rectifier potassium channel 2, MAGNESIUM ION, ETHANOL, ... (4 entities in total)
• Functional Keywords: cytoplasmic assembly, ion channel, beta-barrel, transport protein
• Biological source: Mus musculus (mouse); More
• Cellular location: Membrane ; Multi-pass membrane protein : Q8C4T8
• Total number of polymer chains: 1
• Total formula weight: 23865.43

Authors

Inanobe, A. (deposition date: 2010-04-08, release date: 2010-09-29, Last modification date: 2023-11-01)

Primary citation

Inanobe, A.,Nakagawa, A.,Matsuura, T.,Kurachi, Y.
A structural determinant for the control of PIP2 sensitivity in G protein-gated inward rectifier K+ channels
J.Biol.Chem., 285:38517-38523, 2010

PubMed Abstract: Inward rectifier K(+) (Kir) channels are activated by phosphatidylinositol-(4,5)-bisphosphate (PIP(2)), but G protein-gated Kir (K(G)) channels further require either G protein βγ subunits (Gβγ) or intracellular Na(+) for their activation. To reveal the mechanism(s) underlying this regulation, we compared the crystal structures of the cytoplasmic domain of K(G) channel subunit Kir3.2 obtained in the presence and the absence of Na(+). The Na(+)-free Kir3.2, but not the Na(+)-plus Kir3.2, possessed an ionic bond connecting the N terminus and the CD loop of the C terminus. Functional analyses revealed that the ionic bond between His-69 on the N terminus and Asp-228 on the CD loop, which are known to be critically involved in Gβγ- and Na(+)-dependent activation, lowered PIP(2) sensitivity. The conservation of these residues within the K(G) channel family indicates that the ionic bond is a character that maintains the channels in a closed state by controlling the PIP(2) sensitivity.

PubMed: 20880843
DOI: 10.1074/jbc.M110.161703

Experimental method

X-RAY DIFFRACTION (2.2 Å)