CtBP has been implicated in the progression of many cancers. Cryo-EM structures show that NADH-activated CtBP is a tetramer; mutants that disrupt this tetrameric assembly are defective for oncogenic activity. These results establish the CtBP2 tetramer as transcriptionally active and suggest targeting the tetrameric assembly by cancer therapeutics.

Nojima and Fujita et al. determined the cryo-EM structure of prostaglandin E receptor EP4 bound to the heterotrimeric G protein and the endogenous ligand PGE2. The structure reveals the novel binding mode between GPCRs and Gs, which provides us the information for the structure-based activation mechanism of prostanoid receptors.

Heart contraction depends on interactions between actin and myosin molecules. The cardiac actomyosin interface remained unknown. The structure of cardiac actomyosin complex at near-atomic resolution by Risi et al. provides molecular details of the actomyosin interface and reveals molecular basis of cardiac diseases caused by mutations in actin and myosin.

Khan et al. report the cryo-EM structure of a Cx26 gap junction hemichannel and reveal conservation in the 4-helix bundle within each subunit and the open pore structure compared with the docked GJC. Unlike GJCs, the extracellular loops display conformational flexibility, which may facilitate surveillance and docking of compatible hemichannels in apposed cells.