CPT1A and rheumatoid arthritis: Both the protruding F-actin-rich structures and colocalization of DC-STAMP and clathrin endocytic vesicles were successfully disrupted by CPT1A enzymatic inhibition or CPT1A knockdown (Figures 5J, K), indicating that CPT1A promotes OCP fusion in RA patients via activating clathrin-dependent endocytic activity.