Functional analysis of DDR2 mutations leading to Warburg Cinotti syndrome
File(s)
Author(s)
Hao, Ziteng
Type
Thesis or dissertation
Abstract
Warburg Cinotti syndrome is described as a severe connective tissue disorder, with symptoms related to the hearing system, vision, skin and joints. Exome sequencing of patients revealed that two heterozygous variants (c.1829T>C; p.Leu610Pro and c.2219A>G; p.Tyr740Cys) located within the discoidin domain receptor 2 (DDR2) tyrosine kinase domain were responsible for this disease. We hypothesised that these two mutations may modify the inactive conformation and result in constitutive DDR2 kinase activity as well as changed cellular behaviour through enhanced matrix-induced signalling. In this project, constitutive activities of DDR2-L610P and DDR2-Y740C were observed in both an overexpression system using HEK293 cells and endogenous expression in patient primary fibroblasts. Biochemical and enzymological analysis of soluble recombinant DDR2 kinase constructs revealed the enhanced autophosphorylation and substrate phosphorylation rates found in DDR2-Y740C
compared to DDR2-WT. Compared to WT cells, altered cellular behaviours were found in patient fibroblasts, including increased cell migration on 2D surfaces and enhanced cellinduced collagen gel contraction. Intriguingly, neither of the changes was primarily dependent on DDR2 kinase activity. Moreover, preliminary data revealed a potential relationship between DDR2 and integrin-mediated focal adhesion. These results suggested a
kinase-independent role of DDR2 in regulating some of the functions of Warburg Cinotti fibroblasts. Our data support the hypothesis of constitutive mutant DDR2 kinase activity and changed cellular behaviour as the underlying mechanism of Warburg Cinotti syndrome.
compared to DDR2-WT. Compared to WT cells, altered cellular behaviours were found in patient fibroblasts, including increased cell migration on 2D surfaces and enhanced cellinduced collagen gel contraction. Intriguingly, neither of the changes was primarily dependent on DDR2 kinase activity. Moreover, preliminary data revealed a potential relationship between DDR2 and integrin-mediated focal adhesion. These results suggested a
kinase-independent role of DDR2 in regulating some of the functions of Warburg Cinotti fibroblasts. Our data support the hypothesis of constitutive mutant DDR2 kinase activity and changed cellular behaviour as the underlying mechanism of Warburg Cinotti syndrome.
Version
Open Access
Date Issued
2024-03-27
Date Awarded
2024-08-01
Copyright Statement
Creative Commons Attribution NonCommercial Licence
License URL
Advisor
Leitinger, Birgit
Publisher Department
National Heart & Lung Institute
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)