A schematic representation of Cbl-b/c-Cbl mediates KIT down-regulation. After ligand (SCF) binding, KIT is dimerized and autophosphorylated, leading to recruitment of Src kinases to phosphorylated KIT. Activated Src kinases may lead directly or indirectly to the phosphorylation of Cbl-b and c-Cbl. Cbl's then bind and lead to the ubiquitination and degradation of the activated KIT and themselves in a proteasome- and/or lysosome-dependent manner. In this way, cells become insensitive to SCF. It is possible that there is a feedback loop in this pathway.