FOSL2 and periodontitis: Consistent with our results, previous analyses suggest FOS and JUN downregulation in periodontitis.30 c-FOS and c-JUN, validated at the protein level, are components of the dimeric transcription factor AP-1, consisting primarily of FOS proteins (c-FOS, FOSB, FRA-1, and FRA-2, encoded by FOSL1 and FOSL2) and JUN proteins (c-JUN, JUNB, and JUND).31 These factors regulate cell growth, division, apoptosis, migration, inflammation, and bone turnover.