RABIF (RAB interacting factor) is a guanine nucleotide exchange factor that regulates vesicular transport by acting on RAB GTPases 1. Rather than functioning solely as a traditional GEF, RABIF serves as a Rab-stabilizing holdase chaperone that promotes the stability of multiple RAB proteins including RAB10, RAB8, and RAB13 2. RABIF prevents proteasomal degradation of newly synthesized RAB proteins, with RAB10 being rapidly degraded in RABIF's absence 2. The protein is essential for insulin-stimulated GLUT4 exocytosis in adipocytes and optimal Legionella pneumophila replication through ER recruitment to bacterial-containing vacuoles 21. RABIF facilitates co-translational association with nascent RAB13, directing GTPase activity to promote cell migration 3. Clinically, RABIF is significantly upregulated in multiple cancers including hepatocellular carcinoma, breast cancer, and melanoma, where high expression correlates with poor prognosis 456. In cancer contexts, RABIF promotes tumor progression through regulation of mitophagy, glycolysis, cancer stemness, and metastasis 45. These findings establish RABIF as both a critical regulator of normal vesicular transport and a potential therapeutic target in cancer treatment.