MET and neoplasm: During tumor invasion and metastasis, the ARF6-specific guanine nucleotide exchanging factor (GEF), GEP100 (BRAG2), is recruited to ligand-activated receptor tyrosine kinases (RTKs), such as epidermal growth factor receptor (EGFR) [21], hepatocyte growth factor receptor (also known as c-MET) [22], platelet-derived growth factor receptor β (PDGFRβ) [23], and vascular endothelial cell growth factor receptor 2 (VEGFR2) [24], and activates ARF6 by mediating the change from ARF6-GDP to ARF6-GTP.