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bioRxiv · 10.1101/2023.11.02.565271

The role of the AP-1 adaptor complex in outgoing and incoming membrane traffic

Robinson, M. S.·Antrobus, R.·Sanger, A.·Davies, A. K.·Gershlick, D. C.
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Abstract

The AP-1 adaptor complex is found in all eukaryotes, but it has been implicated in different pathways in different organisms. To look directly at AP-1 function, we generated stably transduced HeLa cells co-expressing tagged AP-1 and various tagged membrane proteins. Live cell imaging showed that AP-1 is recruited onto tubular carriers trafficking from the Golgi apparatus to the plasma membrane, as well as onto transferrin-containing early/recycling endosomes. Analysis of single AP-1 vesicles showed that they are a heterogeneous population, which start to sequester cargo by 30 minutes after exit from the ER. Vesicle capture showed that AP-1 vesicles contain transmembrane proteins found at the TGN and early/recycling endosomes, as well as lysosomal hydrolases, but very little of the anterograde adaptor GGA2. Together, our results support a model in which AP-1 retrieves proteins from post-Golgi compartments back to the TGN, analogous to COPIs role in the early secretory pathway. We propose that this is the function of AP-1 in all eukaryotes. SummaryRobinson et al. investigate AP-1 function using complementary approaches on cells co-expressing tagged AP-1 and cargo proteins. Their results support a model in which AP-1 is recruited onto post-Golgi carriers and early/recycling endosomes, where it retrieves selected proteins back to the TGN.

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Robinson, M. S., Antrobus, R., Sanger, A., Davies, A. K., Gershlick, D. C.. 2023-11-04. The role of the AP-1 adaptor complex in outgoing and incoming membrane traffic. https://doi.org/10.1101/2023.11.02.565271

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