Gene

Cell biology

Ecology

Biology

Protein kinase domain

Receptor

TRPC1

Biochemistry

Transient receptor potential channel

Voltage-gated ion channel

Organic chemistry

Helix (gastropod)

Mutant

TRPM7

Crystallography

Gating

Chemistry

Biophysics

Transmembrane protein

Snail

Ion channel

Proceedings of the National Academy of Sciences

The transient receptor potential ion channel subfamily M, member 7 (TRPM7), is a ubiquitously expressed protein that is required for mouse embryonic development. TRPM7 contains both an ion channel and an α-kinase. The channel domain comprises a nonselective cation channel with notable permeability to Mg2+ and Zn2+ Here, we report the closed state structures of the mouse TRPM7 channel domain in three different ionic conditions to overall resolutions of 3.3, 3.7, and 4.1 Å. The structures reveal key residues for an ion binding site in the selectivity filter, with proposed partially hydrated Mg2+ ions occupying the center of the conduction pore. In high [Mg2+], a prominent external disulfide bond is found in the pore helix, which is essential for ion channel function. Our results provide a structural framework for understanding the TRPM1/3/6/7 subfamily and extend the knowledge base upon which to study the diversity and evolution of TRP channels.

Structure of the mammalian TRPM7, a magnesium channel required during embryonic development