Schematic of SCF:c-kit signaling in the mast cell. On SCF binding at the c-kit receptor tyrosine kinase (RTK), c-kit dimerizes and autophosphorylates. This phosphorylation promotes the conversion of Ras–guanine diphosphate (GDP) to Ras-GTP, which activates PI3K, MAPK, and Rho GTPase signaling pathways. NF1 potentiates the hydrolysis of Ras-GTP to Ras-GDP, the inactive form of Ras.