Citrullination, the spark that ignites the fire in rheumatoid arthritis?

Antibodies directed to proteins containing the amino acid citrulline (e.g. anti-CCP), are extremely specific for rheumatoid arthritis (RA). Since citrulline is a nonstandard amino acid, it is not incorporated into proteins during translation. It can, however, be generated by posttranslational deimination of arginine residues. This process, citrullination, is catalyzed by a group of calcium-dependent peptidylarginine deiminase (PAD) enzymes. The goals of the research described in this thesis were to investigate the presence and nature of citrullinated autoantigens in the synovium and to study the expression and regulation of relevant PAD enzymes.