Structure of the hyperosmolality-gated calcium-permeable channel OSCA1.2

• Published in: Nature communications Vol. 9; no. 1; pp. 5060 - 9
• Main Authors: Liu, Xin, Wang, Jiawei, Sun, Linfeng
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 29.11.2018; Nature Publishing Group; Nature Portfolio
• Subjects: 101/28; 38/23; 38/77; 631/449/2661/2665; 631/45/269/1146; 631/45/535/1258/1259; 631/45/535/1266; 82/80; 82/83; Amino acids; Atomic structure; Calcium; Calcium channels; Calcium permeability; Channels; Electron microscopy; Helices; Humanities and Social Sciences; Laboratories; Life sciences; Lipid bilayers; Lipids; Microscopy; multidisciplinary; Osmotic pressure; Osmotic stress; Permeability; Proteins; Ribonucleic acid; RNA; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-018-07564-5

In plants, hyperosmolality stimuli triggers opening of the osmosensitive channels, leading to a rapid downstream signaling cascade initiated by cytosolic calcium concentration elevation. Members of the OSCA family in Arabidopsis thaliana , identified as the hyperosmolality-gated calcium-permeable channels, have been suggested to play a key role during the initial phase of hyperosmotic stress response. Here, we report the atomic structure of Arabidopsis OSCA1.2 determined by single-particle cryo-electron microscopy. It contains 11 transmembrane helices and forms a homodimer. It is in an inactivated state, and the pore-lining residues are clearly identified. Its cytosolic domain contains a RNA recognition motif and two unique long helices. The linker between these two helices forms an anchor in the lipid bilayer and may be essential to osmosensing. The structure of AtOSCA1.2 serves as a platform for the study of the mechanism underlying osmotic stress responses and mechanosensing. In plants, hyperosmolality stimuli triggers opening of the osmosensitive channels, leading to a rapid downstream signaling cascade. Here, the authors solve the cryo-EM structure of an osmosensitive channel from Arabidopsis OSCA1.2 in its inactivated state.