RANBP1 (RAN Binding Protein 1) is a cytoplasmic-enriched nucleocytoplasmic shuttle protein that plays critical roles in nuclear transport and cell cycle regulation. Functionally, RANBP1 regulates RAN GTPase activity by promoting dissociation of RAN-GTP from nuclear export and import complexes 1, thereby maintaining the nuclear-cytoplasmic gradient essential for protein, nucleic acid, and microRNA transport 2. RANBP1 does not increase RAN GTPase activity directly but enhances GTP hydrolysis mediated by RANGAP1 while inhibiting RCC1-dependent GDP-GTP exchange 3. During mitosis, RANBP1 is required for proper spindle assembly and microtubule dynamics by localizing regulatory factors like cyclin B1 and HURP to spindle microtubules, with depletion causing prometaphase delays and aneuploidy through merotelic attachments 4. In cancer biology, RANBP1 is significantly upregulated in colorectal cancer, lung cancer stem cells, and glioma stem cells, where it promotes proliferation, invasion, and therapy resistance 56. RANBP1 regulates pre-miRNA nuclear export and interacts with CD147 to modulate paclitaxel resistance through microtubule stabilization 7. These findings establish RANBP1 as a potential therapeutic target for cancer and vascular diseases 8.