The p24 Complex Contributes to Specify Arf1 for COPI Coat Selection

• Published in: International journal of molecular sciences Vol. 22; no. 1; p. 423
• Main Authors: Sabido-Bozo, Susana, Perez-Linero, Ana, Manzano-Lopez, Javier, Rodriguez-Gallardo, Sofia, Aguilera-Romero, Auxiliadora, Cortes-Gomez, Alejandro, Lopez, Sergio, Wellinger, Ralf, Muñiz, Manuel
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 03.01.2021; MDPI
• Subjects: ADP-Ribosylation Factor 1 - genetics; ADP-Ribosylation Factor 1 - metabolism; Coat Protein Complex I - genetics; Coat Protein Complex I - metabolism; COP-Coated Vesicles - metabolism; Golgi Apparatus - metabolism; Guanine Nucleotide Exchange Factors - genetics; Guanine Nucleotide Exchange Factors - metabolism; Peptides; Protein Transport; Proteins; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - growth & development; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae Proteins - genetics; Saccharomyces cerevisiae Proteins - metabolism; Yeast; COPI; Golgi; Arf1; p24 complex; ArfGEFs
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms22010423

Golgi trafficking depends on the small GTPase Arf1 which, upon activation, drives the assembly of different coats onto budding vesicles. Two related types of guanine nucleotide exchange factors (GEFs) activate Arf1 at different Golgi sites. In yeast, Gea1 in the cis-Golgi and Gea2 in the medial-Golgi activate Arf1 to form COPI-­coated vesicles for retrograde cargo sorting, whereas Sec7 generates clathrin/adaptor­-coated vesicles at the trans-Golgi network (TGN) for forward cargo transport. A central question is how the same activated Arf1 protein manages to assemble different coats depending on the donor Golgi compartment. A previous study has postulated that the interaction between Gea1 and COPI would channel Arf1 activation for COPI vesicle budding. Here, we found that the p24 complex, a major COPI vesicle cargo, promotes the binding of Gea1 with COPI by increasing the COPI association to the membrane independently of Arf1 activation. Furthermore, the p24 complex also facilitates the interaction of Arf1 with its COPI effector. Therefore, our study supports a mechanism by which the p24 complex contributes to program Arf1 activation by Gea1 for selective COPI coat assembly at the cis-Golgi compartment.