RASGRF1 and rheumatoid arthritis: In contrast, a 54 kDa RasGRF1 C-terminal fragment was detected in all RA and OA FLS lines, a 75 kDa fragment in three of five RA FLS lines and in both OA FLS lines, and a 98 kDa C-terminal fragment in four of six RA lines and in both OA lines.