@article{RiesSanderDeoletal.2019,
  author    = {Ries, Lena K. and Sander, Bodo and Deol, Kirandeep K. and Letzelter, Marie-Annick and Strieter, Eric Robert and Lorenz, Sonja},
  title     = {Analysis of ubiquitin recognition by the HECT ligase E6AP provides insight into its linkage specificity},
  series = {Journal of Biological Chemistry},
  volume    = {294},
  journal   = {Journal of Biological Chemistry},
  number    = {15},
  doi       = {10.1074/jbc.RA118.007014},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-226207},
  pages     = {6113-6129},
  year      = {2019},
  abstract  = {Deregulation of the HECT-type ubiquitin ligase E6AP (UBE3A) is implicated in human papilloma virus-induced cervical tumorigenesis and several neurodevelopmental disorders. Yet the structural underpinnings of activity and specificity in this crucial ligase are incompletely understood. Here, we unravel the determinants of ubiquitin recognition by the catalytic domain of E6AP and assign them to particular steps in the catalytic cycle. We identify a functionally critical interface that is specifically required during the initial formation of a thioester-linked intermediate between the C terminus of ubiquitin and the ligase-active site. This interface resembles the one utilized by NEDD4-type enzymes, indicating that it is widely conserved across HECT ligases, independent of their linkage specificities. Moreover, we uncover surface regions in ubiquitin and E6AP, both in the N- and C-terminal portions of the catalytic domain, that are important for the subsequent reaction step of isopeptide bond formation between two ubiquitin molecules. We decipher key elements of linkage specificity, including the C-terminal tail of E6AP and a hydrophilic surface region of ubiquitin in proximity to the acceptor site Lys-48. Intriguingly, mutation of Glu-51, a single residue within this region, permits formation of alternative chain types, thus pointing to a key role of ubiquitin in conferring linkage specificity to E6AP. We speculate that substrate-assisted catalysis, as described previously for certain RING-associated ubiquitin-conjugating enzymes, constitutes a common principle during linkage-specific ubiquitin chain assembly by diverse classes of ubiquitination enzymes, including HECT ligases.},
  language  = {en}
}
@article{SanderXuEilersetal.2017,
  author    = {Sander, Bodo and Xu, Wenshan and Eilers, Martin and Popov, Nikita and Lorenz, Sonja},
  title     = {A conformational switch regulates the ubiquitin ligase HUWE1},
  series = {eLife},
  volume    = {6},
  journal   = {eLife},
  doi       = {10.7554/eLife.21036},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-171862},
  year      = {2017},
  abstract  = {The human ubiquitin ligase HUWE1 has key roles in tumorigenesis, yet it is unkown how its activity is regulated. We present the crystal structure of a C-terminal part of HUWE1, including the catalytic domain, and reveal an asymmetric auto-inhibited dimer. We show that HUWE1 dimerizes in solution and self-associates in cells, and that both occurs through the crystallographic dimer interface. We demonstrate that HUWE1 is inhibited in cells and that it can be activated by disruption of the dimer interface. We identify a conserved segment in HUWE1 that counteracts dimer formation by associating with the dimerization region intramolecularly. Our studies reveal, intriguingly, that the tumor suppressor p14ARF binds to this segment and may thus shift the conformational equilibrium of HUWE1 toward the inactive state. We propose a model, in which the activity of HUWE1 underlies conformational control in response to physiological cues—a mechanism that may be exploited for cancer therapy.},
  language  = {en}
}