Highlighting the versatility of the citrullination process.

Protein citrullination is one of the processes of post-translational modification of proteins and peptides, playing a crucial role in the homeostasis of important processes, however also leading to pathological processes in autoimmune and neoplastic disorders. Citrullination regulates epidermal function, reproduction being also involved in NET formation. Nowadays, the knowledge about citrullination spreads and opens up a new field for investigation of compounds that potentially be used as a treatment. Inhibitors of PADI are currently being tested in various diseases. As these enzymes play an essential role in the disease progression, one should also look for the basics of regulation of their expression in the cell as well as focus on environmental factors like air pollution or smoking, which can augment the process of citrullination. Despite its pathological properties, citrullination can be a prognostic marker of diseases and a good target for therapies. In this revision, we used PubMed, PubMed Central (PMC), and Google Scholar to collect data which presents information from severalarticles, reviews, case reports, case studies, cohort studies, and clinical trials. Studies conducted in vitro, in vivo on mouse models, postmortem tissue models of animal and human origin were included and non-english articles were excluded. We mainly used keywords like "PAD", Peptidylarginine deiminases", "citrullination" or "deimination" in the search. This revision contains description using both original and review papers can be useful for doctors, scientists, and patients.