Anti-Ro52 Autoantibodies from Patients with Sjögren's Syndrome Inhibit the Ro52 E3 Ligase Activity by Blocking the E3/E2 Interface
Bibliographic record
Abstract
Ro52 (TRIM21) is an E3 ligase of the tripartite motif family that negatively regulates proinflammatory cytokine production by ubiquitinating transcription factors of the interferon regulatory factor family. Autoantibodies to Ro52 are present in patients with lupus and Sjögren's syndrome, but it is not known if these autoantibodies affect the function of Ro52. To address this question, the requirements for Ro52 E3 ligase activity were first analyzed in detail. Scanning a panel of E2 ubiquitin-conjugating enzymes, we found that UBE2D1–4 and UBE2E1–2 supported the E3 ligase activity of Ro52 and that the E3 ligase activity of Ro52 was dependent on its RING domain. We also found that the N-terminal extensions in the class III E2 enzymes affected their interaction with Ro52. Although the N-terminal extension in UBE2E3 made this E2 enzyme unable to function together with Ro52, the N-terminal extensions in UBE2E1 and UBE2E2 allowed for a functional interaction with Ro52. Anti-Ro52-positive patient sera and affinity-purified anti-RING domain autoantibodies inhibited the E3 activity of Ro52 in ubiquitination assays. Using NMR, limited proteolysis, ELISA, and Ro52 mutants, we mapped the interactions between Ro52, UBE2E1, and anti-Ro52 autoantibodies. We found that anti-Ro52 autoantibodies inhibited the E3 ligase activity of Ro52 by sterically blocking the E2/E3 interaction between Ro52 and UBE2E1. Our data suggest that anti-Ro52 autoantibodies binding the RING domain of Ro52 may be actively involved in the pathogenesis of rheumatic autoimmune disease by inhibiting Ro52-mediated ubiquitination. Ro52 (TRIM21) is an E3 ligase of the tripartite motif family that negatively regulates proinflammatory cytokine production by ubiquitinating transcription factors of the interferon regulatory factor family. Autoantibodies to Ro52 are present in patients with lupus and Sjögren's syndrome, but it is not known if these autoantibodies affect the function of Ro52. To address this question, the requirements for Ro52 E3 ligase activity were first analyzed in detail. Scanning a panel of E2 ubiquitin-conjugating enzymes, we found that UBE2D1–4 and UBE2E1–2 supported the E3 ligase activity of Ro52 and that the E3 ligase activity of Ro52 was dependent on its RING domain. We also found that the N-terminal extensions in the class III E2 enzymes affected their interaction with Ro52. Although the N-terminal extension in UBE2E3 made this E2 enzyme unable to function together with Ro52, the N-terminal extensions in UBE2E1 and UBE2E2 allowed for a functional interaction with Ro52. Anti-Ro52-positive patient sera and affinity-purified anti-RING domain autoantibodies inhibited the E3 activity of Ro52 in ubiquitination assays. Using NMR, limited proteolysis, ELISA, and Ro52 mutants, we mapped the interactions between Ro52, UBE2E1, and anti-Ro52 autoantibodies. We found that anti-Ro52 autoantibodies inhibited the E3 ligase activity of Ro52 by sterically blocking the E2/E3 interaction between Ro52 and UBE2E1. Our data suggest that anti-Ro52 autoantibodies binding the RING domain of Ro52 may be actively involved in the pathogenesis of rheumatic autoimmune disease by inhibiting Ro52-mediated ubiquitination.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".