ARFIP1 (ARF interacting protein 1) is a scaffolding protein essential for secretory granule biogenesis at the trans-Golgi network (TGN). Mechanistically, ARFIP1 binds ARF-GTP at the neck of developing secretory granule precursors, forming a protective scaffold that prevents premature fission 1. The protein contains a BAR domain enabling membrane curvature sensing and a phosphatidylinositol 4-phosphate (PI(4)P)-binding amphipathic helix critical for TGN recruitment 2. ARFIP1 also negatively regulates Arl1-mediated retrograde transport 3. Once granule precursors are fully loaded, protein kinase D (PKD/PRKD1) phosphorylates ARFIP1, releasing it from ARFs and permitting granule fission 12. This mechanism ensures proper secretory granule formation in pancreatic beta cells. Beyond glucose regulation, ARFIP1 shows disease relevance as an immunogenetic biomarker in pancreatic neuroendocrine neoplasms (PanNENs), where it is upregulated and associated with immune modulation 4. Additionally, ARFIP1 has been identified as a preoperative diagnostic biomarker for acute kidney injury following cardiac surgery 5 and as a candidate gene in hereditary spinocerebellar ataxia 6. ARFIP1 variants also associate with fertility traits in domesticated yak populations 7.