After one month of doxycycline treatment, two-copy mice developed glomerulosclerosis that resembled focal segmental glomerulosclerosis (FSGS) with urinary shedding of transgene-expressing podocytes. p38 MAPK was activated in podocytes upon CA-Rac1 induction while a p38 inhibitor attenuated proteinuria, podocyte loss, and glomerulosclerosis.