D. B. Grabarczyk

Structures of the UBR4 complex reveal a giant arena to capture diverse substrates for ubiquitin chain elongation.

Recent cryo-EM structures of full-length UBR4 in complex with its cofactors KCMF1 and calmodulin, combined with crystal structures of key domains, reveal how UBR4 employs a giant arena lined with substrate-binding domains to capture defective proteins, as well as the mechanism of K48-specific ubiquitin chain extension.