G3BP2-KIT fusion. (A) Schematic representation of wild-type G3BP2 and KIT and the chimeric fusion between exon (Ex) 7 of G3BP2 and exon 11 of KIT, juxtaposing the first 227 amino acids (AAs) of G3BP2 and the C-terminus portion of KIT including AAs 560 to 976. The joined Exs from both G3BP2 and KIT are in red and bold. The dotted red lines indicate breakpoint positions within Ex 7 and Ex 11 of G3BP2 and KIT, respectively. (B) Gene expression data for G3BP2 and KIT from RNA-seq visualized by the Integrative Genomics Viewer showing overexpression of the KIT portion fused to G3BP2 (hg19). Electropherogram shows the fusion junction between G3BP2 and KIT. (C) Schematic representation of the viral vector used to express fusion protein G3BP2-KIT and TR KIT (TR KIT 560-976AA) in Ba/F3 cell lines and ARF-null pre-B cells. (D) Cytokine-independent assays in Ba/F3 cells and ARF-null pre-B cells expressing the chimeric transcript G3BP2-KIT, the only portion of KIT fused to G3BP2 (encoding for AAs 560 to 976; TR KIT 560-976AA), or empty vector (MIG) cultured without recombinant mouse IL-3 or IL-7. (E) Whole-cell lysates from GFP⁺ sorted Ba/F3 and ARF-null pre-B cells were subjected to protein capillary electrophoresis with the Jess instrument (Protein Simple) with the following antibodies from Cell Signaling: KIT (#3074S), phosphorylated KIT (pKIT) Tyr719 (#3391S), pSTAT5 Tyr694 (#9359S), pSTAT3 Tyr705 (#9145S), pPLCγ1 Tyr783 (#14008S), p44/42 MAPK (Erk1/2; #4695S), p4E-BP1 Thr37/46 (#2855S), and β-actin (#4970S). Borders are used for specifying different antibodies.