Cargo selective vesicle tethering: the structural basis for binding of specific cargo proteins by the Golgi tether component TBC1D23

Cattin-Ortola, J.; Kaufman, J. G. G.; Gillingham, A. K.; Wagstaff, J. L.; Peak-Chew, S.-Y.; Stevens, T. J.; Owen, D. J.; Munro, S.

doi:10.1101/2023.11.22.568253

bioRxiv · 10.1101/2023.11.22.568253

Cargo selective vesicle tethering: the structural basis for binding of specific cargo proteins by the Golgi tether component TBC1D23

Cattin-Ortola, J.·Kaufman, J. G. G.·Gillingham, A. K.·Wagstaff, J. L.·Peak-Chew, S.-Y.·Stevens, T. J.·Owen, D. J.·Munro, S.

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Abstract

For accurate membrane traffic it is essential that vesicles and other carriers tether and fuse to only the correct compartment. The TGN-localised golgins golgin-97 and golgin-245 capture transport vesicles arriving from endosomes via the protein TBC1D23 that forms a bridge between the golgins and endosome-derived vesicles. The C-terminal domain of TBC1D23 is responsible for vesicle capture, but how it recognises a specific type of vesicle was unclear. A search for binding partners of the C-terminal domain surprisingly revealed direct binding to carboxypeptidase D (CPD) and syntaxin-16, both known cargo proteins of the captured vesicles. Binding is via a TLY-containing sequence present in both proteins. A crystal structure reveals how this "acidic TLY motif" binds to the C-terminal domain of TBC1D23. An acidic TLY motif is also present in the tails of other endosome-to-Golgi cargo, and these also bind TBC1D23. Structure-guided mutations in the C-terminal domain that disrupt motif binding in vitro also block vesicle capture in vivo. Thus, TBC1D23 attached to golgin-97 and golgin-245 captures vesicles by a previously undescribed mechanism: the recognition of a motif shared by cargo proteins carried by the vesicle. One sentence summaryA class of transport vesicle destined for the Golgi is recognized by a tether binding directly to the cargo it is carrying.

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Cattin-Ortola, J., Kaufman, J. G. G., Gillingham, A. K., Wagstaff, J. L., Peak-Chew, S.-Y., Stevens, T. J., Owen, D. J., Munro, S.. 2023-11-22. Cargo selective vesicle tethering: the structural basis for binding of specific cargo proteins by the Golgi tether component TBC1D23. https://doi.org/10.1101/2023.11.22.568253

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