7pxf | pdb_00007pxf
Ca2+ free Drosophila Slo channel
Structural highlights
Function[SLO_DROME] Potassium channel activated by both membrane depolarization or increase in cytosolic Ca(2+) that mediates export of K(+). Its activation dampens the excitatory events that elevate the cytosolic Ca(2+) concentration and/or depolarize the cell membrane. It therefore contributes to repolarization of the membrane potential. Kinetics are determined by alternative splicing, phosphorylation status and its combination interaction with Slob and 14-3-3-zeta. While the interaction with Slob1 alone increases its activity, its interaction with both Slob1 and 14-3-3-zeta decreases its activity.[1] [2] Publication Abstract from PubMedSlowpoke (Slo) potassium channels display extraordinarily high conductance, are synergistically activated by a positive transmembrane potential and high intracellular Ca(2+) concentrations and are important targets for insecticides and antiparasitic drugs. However, it is unknown how these compounds modulate ion translocation and whether there are insect-specific binding pockets. Here, we report structures of Drosophila Slo in the Ca(2+)-bound and Ca(2+)-free form and in complex with the fungal neurotoxin verruculogen and the anthelmintic drug emodepside. Whereas the architecture and gating mechanism of Slo channels are conserved, potential insect-specific binding pockets exist. Verruculogen inhibits K(+) transport by blocking the Ca(2+)-induced activation signal and precludes K(+) from entering the selectivity filter. Emodepside decreases the conductance by suboptimal K(+) coordination and uncouples ion gating from Ca(2+) and voltage sensing. Our results expand the mechanistic understanding of Slo regulation and lay the foundation for the rational design of regulators of Slo and other voltage-gated ion channels. Small molecule modulation of the Drosophila Slo channel elucidated by cryo-EM.,Raisch T, Brockmann A, Ebbinghaus-Kintscher U, Freigang J, Gutbrod O, Kubicek J, Maertens B, Hofnagel O, Raunser S Nat Commun. 2021 Dec 9;12(1):7164. doi: 10.1038/s41467-021-27435-w. PMID:34887422[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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