Beyond vesicles and tubules: What matters at ER exit sites?

ER export at ER exit sites (ERES) can occur via COPII-coated vesicles, tubules, or tunnels, and these mechanisms are proposed to coexist rather than be mutually exclusive.

• Why it matters: Prior models treated vesicle, tubule, and tunnel export as separate, rigid pathways, leaving uncertainty about how ERES flexibility is biologically realized.
• What they did: The work overviews existing export mechanisms, explains why they may coexist, and hypothesizes that carrier geometry could be biologically relevant.
• The result: It proposes experimental avenues to resolve disagreements and clarify how ERES geometry and carrier form relate to secretory protein export.