6UZZ

structure of human KCNQ1-CaM complex

Summary for 6UZZ

• Entry DOI: 10.2210/pdb6uzz/pdb
• EMDB information: 20965
• Descriptor: Potassium voltage-gated channel subfamily KQT member 1, Calmodulin-1, CALCIUM ION (3 entities in total)
• Functional Keywords: potassium channel, kcnq1, cam, membrane protein
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 8
• Total formula weight: 320765.10

Authors

Mackinnon, R.,Sun, J. (deposition date: 2019-11-16, release date: 2019-12-04, Last modification date: 2024-03-06)

Primary citation

Sun, J.,MacKinnon, R.
Structural Basis of Human KCNQ1 Modulation and Gating.
Cell, 180:340-347.e9, 2020

PubMed Abstract: KCNQ1, also known as Kv7.1, is a voltage-dependent K channel that regulates gastric acid secretion, salt and glucose homeostasis, and heart rhythm. Its functional properties are regulated in a tissue-specific manner through co-assembly with beta subunits KCNE1-5. In non-excitable cells, KCNQ1 forms a complex with KCNE3, which suppresses channel closure at negative membrane voltages that otherwise would close it. Pore opening is regulated by the signaling lipid PIP2. Using cryoelectron microscopy (cryo-EM), we show that KCNE3 tucks its single-membrane-spanning helix against KCNQ1, at a location that appears to lock the voltage sensor in its depolarized conformation. Without PIP2, the pore remains closed. Upon addition, PIP2 occupies a site on KCNQ1 within the inner membrane leaflet, which triggers a large conformational change that leads to dilation of the pore's gate. It is likely that this mechanism of PIP2 activation is conserved among Kv7 channels.

PubMed: 31883792
DOI: 10.1016/j.cell.2019.12.003

Experimental method

ELECTRON MICROSCOPY (3.1 Å)