TYPHON proteins are RAB-dependent mediators of the trans-Golgi network secretory pathway

• DOI: 10.1093/plcell/koae280
• Publication Date: 2024-10-15T18:47:12Z
• Authors: Anirban Baral; Delphine Gendre; Bibek Aryal; Louise Fougère; Luciano Martin Di...; Chihiro Ohori; Bernadette Sztojka; Tomohiro Uemura; Takashi Ueda; Peter Marhavý; Yohann Boutté; Rishikesh P Bhalerao
• Keywords: Rab; Endomembrane system; Brefeldin A; Transport protein

Abstract The trans-Golgi network (TGN), a key compartment in endomembrane trafficking, participates both secretion to and endocytosis from the plasma membrane. Consequently, TGN plays role plant growth development. Understanding how proteins are sorted for or endocytic recycling at is critical elucidating mechanisms of We previously showed that protein ECHIDNA essential phytohormonal control hypocotyl bending because it mediates cell wall components auxin influx carrier AUXIN RESISTANT 1 (AUX1) TGN. Despite TGN-mediated its mode action remains unknown Arabidopsis (Arabidopsis thaliana). therefore performed suppressor screen on ech mutant. Here, we report identification TGN-localized TYPHON (TPN1) TPN2 proteins. A single amino acid change either TPN causes dominant suppression mutant's defects AUX1 secretion, while also restoring wild-type (WT)-like ethylene-responsive bending. Importantly, genetic biological evidence shows TPN1 acts through RAS-ASSOCIATED BINDING H1b (RABH1b), RAB-GTPase. These results provide insights into ECHIDNA-mediated secretory trafficking carriers TGN, as well controlling growth.