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. 2023 Feb 23;220(5):e20221563. doi: 10.1084/jem.20221563

Figure 4.

Figure 4.

LZTR1 KO has cell context–dependent effects on RIT1 and/or RAS family members but promotes SHP099 resistance through RIT1. (A) LZTR1 KO cells are resistant to SHP099. PrestoBlue assays on parental and LZTR1 KO MOLM13, MV4-11, KU812, KYO1, or K562 cells in 0.5, 2, 5, 5 or 5 µM SHP099, respectively. (B) Cell context–dependent regulation of RIT and RAS family proteins by LZTR1. Parental and LZTR1 KO cells were treated with SHP099 (1 µM) for 1 h, lysed, and analyzed by immunoblotting with the indicated antibodies. Experiments for each line were independently performed for twice. (C) LZTR1 KO increases active RAS levels in K562 cells. MOLM13, MV4-11, and K562 cells were treated with vehicle (DMSO) or 3 µM (MOLM13) or 5 µM (other lines) SHP099 for 1 h, and RAS-GTP levels were assessed by ELISA. All readings were normalized to those of vehicle-treated parental cells for each line. (D) RIT1 KO restores sensitivity of LZTR1 KO cells to SHP099. Parental, LZTR1-KO, and LZTR1-KO plus RIT1-KO MOLM13, MV4-11, and K562 cells were treated with 0.5, 2, and 5 µM SHP099, respectively, for 8 d, and cell number was analyzed by PrestoBlue assay; *, P < 0.05; **, P < 0.01; ***, P < 0.001. Source data are available for this figure: SourceData F4.