RAC1 and rheumatoid arthritis: For example, Tec family kinases have been demonstrated to play a key role in inflammation and bone destruction [40]; the Rho family GTPases members (RhoA, Cdc42 and Rac1) have been reported to be involved in the migration and invasion of RA fibroblast-like synoviocytes [41]; PAK signaling is known to activate JNK pathways that contribute to the induction of immune cell death [42]; mitogen-activated protein kinases/extracellular signal-regulated kinases (MAPK/ERK) signaling pathway is involved in proliferation and migration of RA fibroblast-like synoviocytes [43].