Prof. TIAN Changlin’s team from University of Science and Technology of China (USTC) of the Chinese Academy of Sciences (CAS) published a paper on Cell Research on Sep. 8, reported the Cryo-EM structure of KAT1, the first structure of potassium channel derived from the herb.
Ion channels are hydrophobic proteins that transfer ions across the membrane to insure the balance of the cell. The potassium ion plays a vital role in plants’ metabolism, and KAT1, the channel which transports the ion, processes in a unique way.
Schema of KAT1 regulating the stomata pores on the surface of plant leaves
KAT1 is a relatively rare hyperpolarization inward rectifying potassium channel which has the opposite character compared with typical potassium’s channels: they open over depolarization and vice versa. Meanwhile, potassium floats inward when the channel is open while for animals the ions float outwards. Because of the scarcity of researches related to such regulation, the structural foundation of the regulation remains unclear.
In this work, the revealed Cryo-EM structure suggests KAT1 is equipped with typical non-domain-swapped topological structure which highly resembles pathways of the animals and differs from the pathway’s topological structure like Nav, Cav and etc.
By comparing the KAT1 and other ion channels, scientists found that S4, the voltage sensor, had no relation to the activation of the hyperpolarization. Combining data from diverse researches, it is indicated that the linker between S4 and S5 stably interacts with the C-linker of the S6. Under hyperpolarization, S4 slides inward the membrane to compel S6, thus opens the pathway.
The work elucidated the similarities and differences between KAT1 and other potassium channels and shed lights on the manipulation of ion channels, especially hyperpolarization-activated inwardly rectifying potassium channel.
(Written by MIAO Xinyi, edited by JIANG Pengcen, USTC News Center)
On May 11, the Nature Publishing Group released Nature Publishing Index 2010 China, remarking “a dramatic rise in the quality of research being published by China”. University of Science and Technology of China is ranked 3rd of TOP 10 Institutions in Index 2010 China.
This article came from News Center of USTC.