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Imaging ATG9A, a Multi-Spanning Membrane Protein
Published on: June 16, 2023
A Tca17TRAPPC2L/TRAPPC11/12/13 subcomplex directs TRAPPIII to autophagy
Mario Pinar1, Vivian de Los Ríos2, Silvia Rodríguez-Pires2
1Department of Molecular and Cellular Biosciences, CSIC Centro de Investigaciones Biológicas Margarita Salas, Ramiro de Maeztu, 9. Madrid 28040, Spain.
Journal of Cell Science
|July 22, 2026
Summary
The TRAPP complex regulates membrane trafficking. This study reveals how TRAPPC11/12/13 subunits in Aspergillus nidulans direct TRAPPIII complexes to specific cellular pathways like autophagy.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- TRAPP complexes are crucial for membrane trafficking, with distinct subtypes like TRAPPII and TRAPPIII mediating different cellular processes.
- TRAPPIII complexes, particularly the TRAPPC11/12/13 components, are found in metazoans and plants but absent in budding yeast, necessitating study in other model organisms.
- Understanding the precise roles and assembly of TRAPPIII is essential for deciphering its function in autophagy and ER-Golgi transport.
Purpose of the Study:
- To investigate the function and localization of TRAPPC11/12/13 subunits within the TRAPP complex in the ascomycete Aspergillus nidulans.
- To elucidate the role of Tca17TRAPPC2L in recruiting TRAPPII- and TRAPPIII-specific subunits to the core TRAPP complex.
- To characterize the different versions of TRAPPIII (TRAPPIIIa and TRAPPIIIb) and their specific targeting mechanisms.
Main Methods:
- Localization studies of TRAPPC11 and TRAPPC12 in Aspergillus nidulans.
- Analysis of autophagy impairment upon ablation of TRAPPC11 and TRAPPC12.
- Biochemical characterization of TRAPP subcomplexes involving Tca17TRAPPC2L, TRAPPII, and TRAPPIII subunits.
Main Results:
- TRAPPC11 and TRAPPC12 were found to localize to pre-autophagosomes, and their absence significantly impaired autophagy.
- Two distinct subcomplexes were identified: one containing TRAPPII subunits (Trs120/Trs130/Trs65) and another with TRAPPIII subunits (TRAPPC11/12/13), both recruited by Tca17TRAPPC2L.
- TRAPPIII exists in two forms, TRAPPIIIa and TRAPPIIIb; TRAPPIIIb, containing TRAPPC11/12/13, is specifically targeted to autophagy.
Conclusions:
- Tca17TRAPPC2L plays a pivotal role in determining TRAPP complex function by mediating the recruitment of pathway-specific subunits.
- The TRAPPC11/12/13-containing TRAPPIIIb complex is essential for autophagy in Aspergillus nidulans.
- This study provides a foundation for understanding human TRAPPC11/12/13 mutations and their functional consequences using a tractable fungal model.
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