Structural Basis for the Inhibition of Host Protein Ubiquitination by Shigella Effector Kinase OspG

• Published in: Structure (London) 2014-06, Vol.22 (6), p.878-888
• Main Authors: Grishin, Andrey M., Condos, Tara E.C., Barber, Kathryn R., Campbell-Valois, François-Xavier, Parsot, Claude, Shaw, Gary S., Cygler, Miroslaw
• Format: Article
• Language: English
• Subjects: Activation; Adenosine Triphosphate - metabolism; Attenuation; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Binding Sites; Conjugates; Crystallography, X-Ray; Effectors; Host-Pathogen Interactions - physiology; Human; Humans; Kinases; Models, Molecular; Multiprotein Complexes - chemistry; NF-kappa B - metabolism; Protein Interaction Domains and Motifs; Proteins; Proteolysis; Recruitment; Shigella; Shigella flexneri - genetics; Shigella flexneri - metabolism; Shigella flexneri - pathogenicity; Signal Transduction; Ubiquitin-Conjugating Enzymes - chemistry; Ubiquitin-Conjugating Enzymes - metabolism; Ubiquitin-Protein Ligases - chemistry; Ubiquitin-Protein Ligases - metabolism; Ubiquitination
• ISSN: 0969-2126; 1878-4186
• DOI: 10.1016/j.str.2014.04.010

Shigella invasion of its human host is assisted by T3SS-delivered effector proteins. The OspG effector kinase binds ubiquitin and ubiquitin-loaded E2-conjugating enzymes, including UbcH5b and UbcH7, and attenuates the host innate immune NF-kB signaling. We present the structure of OspG bound to the UbcH7∼Ub conjugate. OspG has a minimal kinase fold lacking the activation loop of regulatory kinases. UbcH7∼Ub binds OspG at sites remote from the kinase active site, yet increases its kinase activity. The ubiquitin is positioned in the “open” conformation with respect to UbcH7 using its I44 patch to interact with the C terminus of OspG. UbcH7 binds to OspG using two conserved loops essential for E3 ligase recruitment. The interaction of the UbcH7∼Ub with OspG is remarkably similar to the interaction of an E2∼Ub with a HECT E3 ligase. OspG interferes with the interaction of UbcH7 with the E3 parkin and inhibits the activity of the E3. [Display omitted] •OspG effector kinase binds UbcH7-Ub conjugate at two separate sites•The OspG active site is accessible in the OspG-UbcH7-Ub complex•UbcH7 binds OspG through the surface involved in E3 ubiquitin ligase binding•OspG inhibits UbcH7-dependent ubiquitination Shigella OspG is an effector kinase that binds ubiquitin and ubiquitin-loaded E2 enzymes and attenuates the host innate immune NF-kB signaling. Grishin et al. present the structure of OspG bound to the UbcH7∼Ub conjugate. This interaction is remarkably similar to the interaction of an E2s∼Ub with a HECT E3 ligase.