AtTRAPPC11 is involved in TRAPPIII mediated control of post-Golgi protein trafficking

Abstract

The plant trans-Golgi Network/Early Endosome (TGN/EE), as an organizer of vesicle trafficking, fulfills a crucial role for plant development and adaptation. Because it coordinates the transport of cell material along different routes, it is expected that a number of TGN/EE associated factors function in the rapid organization of post-Golgi trafficking to ensure that proteins reach their destination. The roles of Transport Protein Particle (TRAPP) complexes in the regulation of plant post-Golgi trafficking start to emerge. We previously demonstrated that the plant TRAPPIII complex is involved in maintenance of TGN organization and function and has a role in endocytic trafficking mediated by the SYP61 TGN/EE compartment. Here we show that attrappc11 mutants display accumulation of the plasma membrane resident proteins CESA6, BRI1 and PIP1;4 in aberrant intracellular compartments. This adds further insights into the functions of TRAPPIII as a regulators of post-Golgi/endosomal traffic.

TheArabidopsis thalianaTRAPPIII subunit AtTRAPPC8/AtTRS85 is involved in ER functioning and autophagy

“…Currently available data suggest that TRAPPII activates not only members of the RabA (homologous to the animal Rab11 family) and RabD (homologous to the Rab1 family) clades, but also members of the B and E clades (Kalde et al, 2019). Data obtained previously for the C11 subunit of TRAPPIII suggest a possible role as a membrane tether at the TGN/EE (Rosquete et al, 2019 a, b), possibly as a GEF for RabD2. In this scenario, TRAPPIII would be involved in Golgi and post-Golgi trafficking, and endocytic sorting and recycling of specific components.…”

Plant endosomes as protein sorting hubs

“…In Arabidopsis , TRAPPC11, a putative component of the plant TRAPP‐III complex, localizes to the TGN and mediates the localization of SYP61. The tappc11 mutant shows abnormal TGN morphology, mistargeting of plasma membrane proteins (e.g., brassinosteroid receptor BRASSINOSTEROID INSENSITIVE 1 or BRI1, cellulose synthases, PIP1:4) to aberrant cytoplasmic compartments [83], and reduced labeling of the TGN with the endocytic tracer FM4‐64, likely due to impaired tethering or fusion of endocytic vesicles with the TGN [84].…”