The Plant Trans-Golgi Network: Not Just a Matter of Distinction

Rosquete, Michel Ruiz; Davis, Destiny J.; Drakakaki, Georgia

doi:10.1104/pp.17.01239

Cited by 71 publications

(56 citation statements)

References 172 publications

(206 reference statements)

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“…During cell division, one of these domains forms the cell plate (Chow et al ., ; Ravikumar et al ., ), a structure unique to plant cytokinesis. The plant TGN/EE has essential functions in exocytosis, endocytosis and protein sorting as well as a number of specialized functions such as cell plate formation in dividing cells (Luo et al ., ; Ravikumar et al ., ; Rosquete et al ., ). In Arabidopsis, all of these functions are, at least in part, mediated by the Transport Protein Particle II (TRAPPII) complex.…”

Section: Introductionmentioning

confidence: 97%

Interactions between Transport Protein Particle (TRAPP) complexes and Rab GTPases in Arabidopsis

et al. 2019

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Transport Protein Particle II (TRAPPII) is essential for exocytosis, endocytosis, protein sorting and cytokinesis. In spite of a considerable understanding of its biological role, little information is known about Arabidopsis TRAPPII complex topology and molecular function. In this study, independent proteomic approaches initiated with TRAPP components or Rab-A GTPase variants converge on the TRAPPII complex. We show that the Arabidopsis genome encodes the full complement of 13 TRAPPC subunits, including four previously unidentified components. A dimerization model is proposed to account for binary interactions between TRAPPII subunits. Preferential binding to dominant negative (GDP-bound) versus wild-type or constitutively active (GTP-bound) RAB-A2a variants discriminates between TRAPPII and TRAPPIII subunits and shows that Arabidopsis complexes differ from yeast but resemble metazoan TRAPP complexes. Analyzes of Rab-A mutant variants in trappii backgrounds provide genetic evidence that TRAPPII functions upstream of RAB-A2a, allowing us to propose that TRAPPII is likely to behave as a guanine nucleotide exchange factor (GEF) for the RAB-A2a GTPase. GEFs catalyze exchange of GDP for GTP; the GTP-bound, activated, Rab then recruits a diverse local network of Rab effectors to specify membrane identity in subsequent vesicle fusion events. Understanding GEFÀRab interactions will be crucial to unravel the co-ordination of plant membrane traffic.280 Monika Kalde et al. c The log 2 intensity ratio for each protein was calculated from its average signal intensity in the experiment divided by its average intensity in the control, which was an empty soluble GFP vector. Detected TRAPP subunits were ranked according to their ratio between the experiment and negative control. The proteins are sorted by rank. Note that TRS65/TRAPPC13, which is a TRAPPII subunit in yeast but a TRAPPIII subunit in metazoans, had an intermediate intensity ratio of 7. 3 (see Figure S1). The high confidence interactors include shared and TRAP-PII-specific subunits. d P-values were calculated using the t-test (two-sided) and are all significant (P < 0.02) with the exception of those for TRAPPIII homologues, which are in red. This table lists only TRAPP components detected in the IPs. Related to Figure S1 on the CLUB interactome.

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Section: Introductionmentioning

confidence: 97%

Interactions between Transport Protein Particle (TRAPP) complexes and Rab GTPases in Arabidopsis

et al. 2019

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“…The trans-Golgi network, or TGN, is emerging as a major hub for the flow and sorting of information from and to the cell surface (Gendre et al, 2015;Rosquete et al, 2018;Uemura and Nakano, 2013). At the TGN, macromolecules are sorted into different populations of vesicles destined for the cell surface or for the vacuole.…”

Section: Introductionmentioning

confidence: 99%

“…As it is the first point of entry for information from the cell surface, the TGN is also referred to as an early endosome in plants (Dettmer et al, 2006). The TGN plays three essential functions in membrane trafficking: exocytosis, endocytosis and protein sorting (Rosquete et al, 2018). In addition, it plays important roles in more specialized cellular processes, such as the establishment of polarity, cell differentiation, anisotropic growth and cytokinesis (Gendre et al, 2015;Ravikumar et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Independent yet overlapping pathways ensure the robustness and responsiveness of trans-Golgi network functions in Arabidopsis

et al. 2018

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The trans-Golgi-network (TGN) has essential housekeeping functions in secretion, endocytosis and protein sorting, but also more specialized functions in plant development. How the robustness of basal TGN function is ensured while specialized functions are differentially regulated is poorly understood. Here, we investigate two key regulators of TGN structure and function, ECHIDNA and the Transport Protein Particle II (TRAPPII) tethering complex. An analysis of physical, network and genetic interactions suggests that two network communities are implicated in TGN function and that ECHIDNA and TRAPPII belong to distinct yet overlapping pathways. Whereas ECHIDNA and TRAPPII colocalized at the TGN in interphase cells, their localization diverged in dividing cells. Moreover, ECHIDNA and TRAPPII localization patterns were mutually independent. TGN structure, endocytosis and sorting decisions were differentially impacted in echidna and trappii mutants. Our analyses point to a partitioning of specialized TGN functions, with ECHIDNA being required for cell elongation and TRAPPII for cytokinesis. Two independent pathways able to compensate for each other might contribute to the robustness of TGN housekeeping functions and to the responsiveness and fine tuning of its specialized functions.

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“…Studies using adaptor protein complex (AP) mutants indicate that the transport vectors in this latter case may be clathrin-coated vesicles. There is also some evidence to suggest that some of the TGN-derived vesicles (AP-4-positive, but lacking clathrin) might bypass the endosomes (Rosquete et al, 2018). In accordance with this notion, it has been recently demonstrated that two different tethering complexes (CORVET and HOPS) exist for fusion with the tonoplast in Arabidopsis (Arabidopsis thaliana; Takemoto et al, 2018).…”

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confidence: 85%