SEC16A is a molecular scaffold protein that organizes endoplasmic reticulum exit sites (ERES), specialized membrane domains essential for secretory protein transport. SEC16A assembles in a SAR1A-GTP-dependent manner to form the structural framework defining functional ERES 12. This scaffolding function is critical for coat protein complex II (COPII) formation and recruitment of cargo-binding proteins like MIA3/TANGO to coordinate ER-to-Golgi vesicular transport 34. SEC16A regulates both conventional ER/Golgi-dependent secretion and GORASP2-mediated unconventional trafficking, as demonstrated with CFTR transport 5. Phosphorylation state balance—maintained through FAM83A/CK1α phosphorylation and PPP6C/PPP1C dephosphorylation—is essential for sustaining proper ERES function 6. SEC16A also positively regulates protein stability of E3 ubiquitin-protein ligases RNF152 and RNF183. Functionally, SEC16A acts as a growth factor-responsive integrator linking proliferation to secretion capacity 7. SEC16A variants predispose to chr9 pancreatitis by impairing COPII assembly and inducing ER stress 4, establishing clinical relevance in protein trafficking-dependent disease pathogenesis.