Protein post-translational modifications like glycation, carbamylation and 
citrullination increase the functional diversity of the proteome but in disease 
situations might do more harm than good. Post-translational modifications of ECM 
proteins are thus appearing as mechanisms, which contribute to tissue 
dysfunction in chronic kidney disease, in diabetes and in various inflammatory 
diseases. In chronic renal failure, carbamylation could lead to kidney fibrosis. 
In diabetes, high glucose levels lead to non-enzymatic glycation and 
cross-linking of collagens, which contribute to tissue stiffening with 
consequences for cardiovascular and renal functions. In inflammatory diseases, 
citrullination deiminates arginine residues with possible consequences for 
integrin-mediated cell adhesion to RGD- and GFOGER sequences in ECM proteins. 
Citrullination of fibronectin was in one study suggested to affect cell adhesion 
by modifying the heparin-binding site and not the RGD site. In a recent 
publication citrullination of GFOGER sequences in collagen II was demonstrated 
to selectively affect α10β1 and α11β1 integrin-mediated cell adhesion to 
collagen II, with consequences for synovial fibroblast and stem cell adhesion 
and migration. The implications of citrullination affecting integrin binding in 
disease open up a new area of study and might have implications for the 
pathogenesis of inflammatory diseases like rheumatoid arthritis and 
periodontitis.