The monolayers were treated and RPTC functions analyzed as described under “Experimental Procedures.” White columns, controls; black columns, 50 μm cisplatin; light gray columns, 50 μm PD98059 + 50 μm cisplatin; dark gray columns, 10 nm Go6976 + 50 μm cisplatin; hatched columns, 3 μm UO126 + 50 μm cisplatin; striped columns, 50 μm zVAD-fmk + 50 μm cisplatin. Results are the average ± S.E. of three to five independent experiments (RPTC isolations).