18 / 2021-07-14 21:35:36

Crystallographic Studies of Insect Ryanodine Receptor Domains

Ryanodine receptor,insecticide,resistance,N-terminal domain,SPRY domain,Repeat34 domain

Ryanodine receptors (RyRs) are large calcium release channels located in the sarcoplasmic reticulum (SR)/endoplasmic reticulum (ER) membrane, which play an important role in calcium signaling. RyR is the target of a family of bestselling insecticides, named diamide insecticides. However, due to the heavy usage, several pests have been shown to develop resistance due to mutations identified in their RyR transmembrane domain. Insecticidal molecules targeting the binding sites located in the non-transmembrane region of the insect RyR, other than the conventional diamide pocket located in the transmembrane region, would be an attractive approach to overcome the current resistance problem. We solved the crystal structures of several insect RyR cytosolic domains, including the N-terminal domains (NTD) from both P. xylostella and A. mellifera and Repeat34 and SPRY2 domains from P. xylostella, revealing several pest-specific structural features located in the inter-domain interfaces that are important for channel gating. In addition, Repeat34 domain contains a number of insect-specific temperature-dependent PKA phosphorylation sites which have been found to be involved in the regulation of channel activity. Several potential insecticidal compounds have been identified through structure-based screening and validated by cell-based and insect-based functional assays.