Related Experiment Video
Updated: Apr 16, 2026
Native Polyacrylamide Gel Electrophoresis Immunoblot Analysis of Endogenous IRF5 Dimerization
Published on: October 6, 2019
Disease-associated mutations in IRF6 and RIPK4 dysregulate their signalling functions
Mei Qi Kwa1, Jennifer Huynh1, Eric C Reynolds2
1Oral Health Cooperative Research Centre, Melbourne Dental School, The University of Melbourne, Victoria 3010, Australia; Bio21 Institute, The University of Melbourne, Victoria 3010, Australia; Department of Medicine, Royal Melbourne Hospital, The University of Melbourne, Victoria 3010, Australia.
Abstract:
IRF6 and RIPK4 are critical regulators of keratinocyte differentiation and their mutation cause the developmental syndromes Van der Woude syndrome (VWS) and Bartsocas-Papas syndrome (BPS), respectively. RIPK4 promotes keratinocyte differentiation, in part, by inducing IRF6 transactivator function through the phosphorylation of its C-terminal domain at Ser413 and Ser424. Although more than 200 IRF6 mutations have been identified in VWS, a p.Arg412X nonsense mutation is particularly prevalent. A RIPK4 p.Ser376X nonsense mutation in BPS was also recently identified. Here, we demonstrated for the first time that the truncation of IRF6 at Arg412 causes its rapid proteasome-dependent degradation. The truncation of IRF6 also prevented the induction of its transactivator function by RIPK4. Similarly, the p.Ser376X mutation in RIPK4 impaired its induction of IRF6 transactivator function. The mutation also inhibited the stabilisation of β-catenin by RIPK4, and thus may additionally impair Wnt signalling. Collectively, our findings provide important mechanistic insight into how the p.Arg412X and p.Ser376X mutations may cause VWS and BPS, respectively.
Insights
Mutations in IRF6 and RIPK4 disrupt keratinocyte differentiation, causing VWS and BPS. Truncated IRF6 degrades rapidly, while RIPK4 mutations impair IRF6 function and Wnt signaling, explaining disease mechanisms.
Area of Science:
- Molecular Biology
- Developmental Biology
- Genetics
Background:
- IRF6 and RIPK4 are crucial for keratinocyte differentiation.
- Mutations in IRF6 and RIPK4 cause Van der Woude syndrome (VWS) and Bartsocas-Papas syndrome (BPS).
- RIPK4 activates IRF6 via phosphorylation, promoting differentiation.
Purpose of the Study:
- To investigate the molecular mechanisms of VWS and BPS caused by specific IRF6 and RIPK4 mutations.
- To elucidate how IRF6 p.Arg412X and RIPK4 p.Ser376X mutations impact protein function and cellular processes.
Main Methods:
- Proteasome-dependent degradation assays.
- Analysis of IRF6 transactivator function induction by RIPK4.
- Assessment of β-catenin stabilization by RIPK4.
Main Results:
- IRF6 truncation at Arg412 leads to rapid proteasomal degradation.
- RIPK4 fails to induce transactivator function in truncated IRF6.
- RIPK4 p.Ser376X mutation impairs IRF6 activation and β-catenin stabilization, potentially affecting Wnt signaling.
Conclusions:
- The study provides mechanistic insights into VWS and BPS pathogenesis.
- IRF6 p.Arg412X mutation causes disease via protein degradation and loss of RIPK4-mediated activation.
- RIPK4 p.Ser376X mutation contributes to BPS by impairing IRF6 function and Wnt signaling pathways.
Related Concept Videos
01:31Regulation of the Unfolded Protein Response
01:22PI3K/mTOR/AKT Signaling Pathway
01:37The Unfolded Protein Response
01:15Receptor Downregulation in MVBs
The EGFR can initiate signaling pathways that lead to cell proliferation, migration, and differentiation. Overexpression of EGFR stimulates cells to proliferate. Excessive EGFR...
01:20The JAK-STAT Signaling Pathway
01:07MAPK Signaling Cascades