The pathways of secretory cargo export at the endoplasmic reticulum

Palade’s original model proposed that secretory cargo is transported between stable compartments via vesicles. However, recent findings challenge this view, suggesting that secretory pathway compartments are dynamic, with cargo itself dictating whether transfer occurs via vesicles or through the continuity and maturation of compartmental structures. At the heart of this process is TANGO1, a key component of a molecular machine that works in concert with COPII proteins to construct export routes tailored to the size and quantity of secretory cargo. The author presents an overview of the complex challenge of protein export from the Endoplasmic Reticulum, and discusses how cells may deploy novel pathways utilizing specialized proteins to construct customized transport routes, precisely calibrated to meet physiological demands.