[PDF][PDF] SURF4-induced tubular ERGIC selectively expedites ER-to-Golgi transport

R Yan, K Chen, B Wang, K Xu - Developmental cell, 2022 - cell.com
Developmental cell, 2022cell.com
The endoplasmic reticulum (ER)-to-Golgi transport is critical to protein secretion and
intracellular sorting. Here, we report a highly elongated tubular ER-Golgi intermediate
compartment (t-ERGIC) that selectively expedites the ER-to-Golgi transport for soluble
cargoes of the receptor SURF4. Lacking the canonical ERGIC marker ERGIC-53 yet positive
for the small GTPases Rab1A/B, the t-ERGIC is further marked by its extraordinarily
elongated and thinned shape. With its large surface-to-volume ratio, high intracellular …
Summary
The endoplasmic reticulum (ER)-to-Golgi transport is critical to protein secretion and intracellular sorting. Here, we report a highly elongated tubular ER-Golgi intermediate compartment (t-ERGIC) that selectively expedites the ER-to-Golgi transport for soluble cargoes of the receptor SURF4. Lacking the canonical ERGIC marker ERGIC-53 yet positive for the small GTPases Rab1A/B, the t-ERGIC is further marked by its extraordinarily elongated and thinned shape. With its large surface-to-volume ratio, high intracellular traveling speeds, and ER-Golgi recycling capabilities, the t-ERGIC accelerates the trafficking of SURF4-bound cargoes. The biogenesis and cargo selectivity of t-ERGIC both depend on SURF4, which recognizes the N terminus of soluble cargoes and co-clusters with the selected cargoes to expand the ER-exit site. In the steady state, the t-ERGIC-mediated fast ER-to-Golgi transport is antagonized by the KDEL-mediated ER retrieval. Together, our results argue that specific cargo-receptor interactions give rise to distinct transport carriers that regulate the trafficking kinetics.
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