Biology subjects

Sabido-Bozo, S.

Publications and source records attributed to Sabido-Bozo, S..

3 recordsLinked to original sources

bioRxiv2026

Contact of mobile cis-Golgi network with ER exit sites executes COPI-mediated receptor recycling

COPI-mediated retrograde transport is essential for maintaining homeostasis between the endoplasmic reticulum (ER) and the Golgi in eukaryotic cells. However, its spatiotemporal dynamics remain unclear. In budding yeast, ER export occurs through a hug-and-kiss mechanism, wherein mobile cis-Golgi network (CGN) elements transiently approach ER exit sites (ERES) to capture cargo before departing to deliver it to the Golgi. Here, using high-resolution 3D and 4D live imaging, we show that the COPI-mediated recycling of a cargo receptor from the CGN back to the ER occurs during the hug-and-kiss event. Furthermore, this recycling is complete before the CGN detaches from the ERES, suggesting that COPI-mediated retrograde transport is spatiotemporally coupled to ER export during a single and transient CGN-ERES association. Consistent with this model, when COPI function is impaired, the receptor fails to return efficiently to the ER and instead remains in the CGN after separation from the ERES. Additionally, COPI impairment prolonged CGN-ERES association, suggesting that COPI function also facilitates CGN detachment from ERES. Thus, we propose that rapid COPI-mediated recycling drives CGN maturation directly at the ERES interface, enabling the CGN to detach and proceed along the secretory pathway.

cell biology↗

bioRxiv2024

ER sensing of lipid metabolism drives PRA family-dependent regulation of COPII vesicle transport

Newly synthesized secretory proteins and many lipids are transported from the endoplasmic reticulum (ER) to the Golgi prior to their ultimate destinations. The ER-to-Golgi transport must be tightly regulated during adaptation to environmental stress. However, the sensing mechanism and regulatory pathways governing the consecutive formation, budding and transportation of COPII vesicles from the ER remain insufficiently explored. Here, we present evidence indicating that COPII-mediated vesicle transport is transcriptionally controlled through the phosphatidic acid-dependent Opi1-Ino2/Ino4 regulatory circuit. Our analysis indicates that YIP3, a target gene of Ino2/Ino4, exerts a negative regulatory impact on COPII-mediated vesicle transport. Furthermore, we demonstrated that Ino2/Ino4 but not Yip3 modulates Sar1 activation, the initial step in COPII vesicle formation, whereas Yip3 hinders Sec16 assembly on the ER membrane, thereby implying that Ino2/Ino4 governs COPII-mediated trafficking at multiple steps. Thus, this study provides the first evidence for an ER sensing system that transcriptionally fine-tunes multiple steps of anterograde vesicular transport in response to alterations in lipid composition of the ER membrane.

cell biology↗

bioRxiv2020

The P4-ATPase Drs2 regulates the homeostasis of Atg9

Multisubunit Tethering Complexes (MTCs) are a set of conserved protein complexes that tether transported vesicles at the acceptor membrane. Interactions with other components of the trafficking machinery regulate MTCs through mechanisms that are just partially understood. Here we systematically investigate the interactome that regulates the function of MTCs. We found that P4-ATPases, a family of lipid transporters involved in the biogenesis of vesicles, interact with MTCs that participate in the anterograde and retrograde transport at the Golgi, such as TRAPPIII. We used the lipid flippase Drs2 as a model to investigate the mechanism and biological relevance of such interplay during the transport of Atg9 vesicles. Binding to the N-terminal tail of Drs2 stabilizes TRAPPIII on membrane compartments loaded with Atg9 and it is required for the delivery of Atg9 during selective autophagy, a role that is independent of previously reported functions of the P4-ATPase. This mechanism relies on the I(S/R)TTK motif nested in the N-terminal tail cavity of Drs2, a motif that is required for the interaction with MTCs.

cell biology↗