Anti β actin clone 13e5

Anti-KEAP1 (clone D6B12, #8047, 1:1000), anti-βactin (clone 13E5, #4970, 1:4000), anti-LKB1 (clone D60C5, #3047, 1:1000), anti-Vinculin (#4650, 1:4000), anti-TP53BP1(#4937,1:1000), anti-βcatenin (clone D10A8, #25362, 1:2000), anti-phospho-p44/42 MAPK (#9101, 1:3000), anti-phospho-MEK1/2 (clone 41G9, #9154, 1:1000 dilution), anti-xCT/SLC7A11(clone D2M7A, #12691, 1:1000) were from Cell Signaling Technology, MA. Anti-NRAS antibody (#ab77392) was from Abcam, MA. Erastin (#17754) was from Cayman Chemical. Sotorasib (#HY-114277) used ex vivo was from MedChemExpress.

Cells were lysed in RIPA buffer (Cell Signaling Technology, Danvers MA, USA) in the presence of protease inhibitor cocktail (Roche, Basel, Switzerland). Lysed material was clarified by centrifugation at 12,000g for 10 min at 4 °C. Clarified extracts representing 30 × 10⁵ cells per lane were fractionated on a 10% Bis-Tris gel and transferred to a polyvinylidene difluoride membrane using a transfer apparatus according to the manufacturer’s protocol (Bio-Rad, Hercules, CA, USA). Membranes were blocked for 1 h with 5% nonfat milk in TBST (10 mM Tris, pH 8.0, 150 mM NaCl abd 0.5% Tween 20). Membranes were washed 1× in TBST, and incubated with anti-β-actin (clone 13E5, 1:1000 dilution, Cell Signaling Technology, Danvers MA, USA) and anti-PPP6C (clone ab131335, 1:1000 dilution, Abcam, Cambridge, United Kingdom) for 18 h at 4 °C. Membranes were washed three times with TBST and were incubated with a 1:2,500 dilution of horseradish peroxidase–conjugated polyclonal goat antibody to rabbit (catalog number 7074; Cell Signaling Technology, Danvers MA, USA) for 1 h at RT. Membranes were washed three times with TBST, developed with the ECL system (Amersham Biosciences) and visualized on a ChemiDoc imaging system (Bio-Rad, Hercules, CA, USA) per the manufacturer’s protocols. Full images and size marker standards are presented in Supplementary Figure 6.