Transport protein particle (TRAPP) I is a multisubunit vesicle tethering factor composed of seven subunits involved in ER-to-Golgi trafficking. The functional mechanism of the complex and how the subunits interact to form a functional unit are unknown. Here, we have used a multidisciplinary approach that includes X-ray crystallography, electron microscopy, biochemistry, and yeast genetics to elucidate the architecture of TRAPP I. The complex is organized through lateral juxtaposition of the subunits into a flat and elongated particle. We have also localized the site of guanine nucleotide exchange activity to a highly conserved surface encompassing several subunits. We propose that TRAPP I attaches to Golgi membranes with its large flat surface containing many highly conserved residues and forms a platform for protein-protein interactions. This study provides the most comprehensive view of a multisubunit vesicle tethering complex to date, based on which a model for the function of this complex, involving Rab1-GTP and long, coiled-coil tethers, is presented.
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http://dx.doi.org/10.1016/j.cell.2006.09.029 | DOI Listing |
Sci Rep
December 2024
School of Life Sciences, Qilu Normal University, Jinan, 250200, China.
In yeast and mammals, the EXO70 subunit of the exocyst complex plays a key role in mediating the tethering of exocytic vesicles to the plasma membrane (PM). In plants, however, the role of EXO70 in regulating vesicle tethering during exocytosis remains unclear. In land plants, EXO70 has undergone significant evolutionary expansion, resulting in multiple EXO70 paralogues that may allow the exocyst to form various isoforms with specific functions.
View Article and Find Full Text PDFPlant Physiol Biochem
December 2024
Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education)/College of Horticulture and Landscape Architecture, Southwest University, Chongqing, 400715, China; State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University/Academy of Agricultural Sciences of Southwest University, Chongqing, 400715, China. Electronic address:
Rab GTPases are a class of small GTP-binding proteins, play crucial roles in the membrane transport machinery with in eukaryotic cells. They dynamically regulate the precise targeting and tethering of transport vesicles to specific compartments by transitioning between active and inactive states. In plants, Rab GTPases are classified into eight distinct subfamilies: Rab1/D, Rab2/B, Rab5/F, Rab6/H, Rab7/G, Rab8/E, Rab11/A, and Rab18/C.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
December 2024
Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599.
Adaptor protein complex-3 (AP-3) mediates cargo sorting from endosomes to lysosomes and lysosome-related organelles. Recently, it was shown that AP-3 adopts a constitutively open conformation compared to the related AP-1 and AP-2 coat complexes, which are inactive until undergoing large conformational changes upon membrane recruitment. How AP-3 is regulated is therefore an open question.
View Article and Find Full Text PDFMol Plant Pathol
December 2024
Plant Metabolism Group, Leibniz-Institute of Vegetable and Ornamental Crops (IGZ), Großbeeren, Germany.
Many gram-negative pathogenic bacteria use type III effector proteins (T3Es) as essential virulence factors to suppress host immunity and to cause disease. However, in many cases the molecular function of T3Es remains unknown. The plant pathogen Xanthomonas campestris pv.
View Article and Find Full Text PDFEMBO Rep
December 2024
Program of Life and Environmental Science, Graduate School of Integral Science for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8521, Japan.
Live imaging of secretory cargoes is a powerful method for understanding the mechanisms of membrane trafficking. Inducing the synchronous release of cargoes from an organelle is key for enhancing microscopic observation. We developed an optical cargo-releasing method, 'retention using dark state of LOV2' (RudLOV), which enables precise spatial, temporal, and quantity control during cargo release.
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