Diacidic Motifs Influence the Export of Transmembrane Proteins from the Endoplasmic Reticulum in Plant Cells

Hanton, Sally L.; Renna, Luciana; Bortolotti, Lauren E.; Châtre, Laurent; Stefano, Giovanni; Brandizzí, Federica

doi:10.1105/tpc.105.034900

Cited by 98 publications

(109 citation statements)

References 67 publications

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“…Our findings provide evidence for increased recruitment of Sec24 to ERES upon coexpression of the Golgi membrane markers ERD2-GFP or TMcCCASP (Hanton et al, 2005b). Mutagenesis experiments revealed that this effect is strictly dependent on the diacidic ER export signal DXE (Hanton et al, 2005b).…”

mentioning

confidence: 58%

“…An ER export signal for ERD2 has yet to be discovered, but it has been shown in yeast that Sec24 can interact with diacidic motifs in the cytosolic tails of membrane proteins (Votsmeier and Gallwitz, 2001). We have previously shown that diacidic export motifs are functional in plants because mutation of these signals strongly reduced the export of different membrane proteins from the ER (Hanton et al, 2005b).…”

Section: Eres Formation and Copii Recruitment To Eres Are Signal Depementioning

confidence: 99%

“…Of particular use for our present investigation is TMcCCASP, a chimeric type I protein (Hanton et al, 2005b) consisting of a form of GFP carrying a signal peptide for entry into the ER and an N-glycosylation site (Batoko et al, 2000) fused to a 17-amino acid transmembrane domain, the short length of which restricts type I proteins to the ER (Brandizzi et al, 2002a). Adjacent to the transmembrane domain are 78 amino acids of the cytosolic domain of CASP (Hanton et al, 2005b;Renna et al, 2005), containing a functional diacidic ER export motif that is dominant over the properties of the transmembrane domain and permits Figure 1.…”

Section: Eres Formation and Copii Recruitment To Eres Are Signal Depementioning

confidence: 99%

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De Novo Formation of Plant Endoplasmic Reticulum Export Sites Is Membrane Cargo Induced and Signal Mediated

et al. 2007

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The plant endoplasmic reticulum (ER) contains functionally distinct subdomains at which cargo molecules are packed into transport carriers. To study these ER export sites (ERES), we used tobacco (Nicotiana tabacum) leaf epidermis as a model system and tested whether increased cargo dosage leads to their de novo formation. We have followed the subcellular distribution of the known ERES marker based on a yellow fluorescent protein (YFP) fusion of the Sec24 COPII coat component (YFP-Sec24), which, differently from the previously described ERES marker, tobacco Sar1-YFP, is visibly recruited at ERES in both the presence and absence of overexpressed membrane cargo. This allowed us to quantify variation in the ERES number and in the recruitment of Sec24 to ERES upon expression of cargo. We show that increased synthesis of membrane cargo leads to an increase in the number of ERES and induces the recruitment of Sec24 to these ER subdomains. Soluble proteins that are passively secreted were found to leave the ER with no apparent up-regulation of either the ERES number or the COPII marker, showing that bulk flow transport has spare capacity in vivo. However, de novo ERES formation, as well as increased recruitment of Sec24 to ERES, was found to be dependent on the presence of the diacidic ER export motif in the cytosolic domain of the membrane cargo. Our data suggest that the plant ER can adapt to a sudden increase in membrane cargo-stimulated secretory activity by signal-mediated recruitment of COPII machinery onto existing ERES, accompanied by de novo generation of new ERES.

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confidence: 58%

Section: Eres Formation and Copii Recruitment To Eres Are Signal Depementioning

confidence: 99%

Section: Eres Formation and Copii Recruitment To Eres Are Signal Depementioning

confidence: 99%

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De Novo Formation of Plant Endoplasmic Reticulum Export Sites Is Membrane Cargo Induced and Signal Mediated

et al. 2007

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“…The differential inhibitory effect of AtPRA1.B6 can also be observed if the COPII-dependent exit of cargo proteins from the ER is mediated by multiple pathways. Indeed, certain cargoes, such as GONST1, CASP, and KAT, exit the ER in a sorting signal-dependent manner, whereas a-amylase is secreted from the ER by the default or bulk flow pathway (Denecke et al, 1990;Phillipson et al, 2001;Hanton et al, 2005;Sieben et al, 2008).…”

Section: Discussionmentioning

confidence: 99%

An Arabidopsis Prenylated Rab Acceptor 1 Isoform, AtPRA1.B6, Displays Differential Inhibitory Effects on Anterograde Trafficking of Proteins at the Endoplasmic Reticulum

et al. 2011

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Prenylated Rab acceptors (PRAs), members of the Ypt-interacting protein family of small membrane proteins, are thought to aid the targeting of prenylated Rabs to their respective endomembrane compartments. In plants, the Arabidopsis (Arabidopsis thaliana) PRA1 family contains 19 members that display varying degrees of sequence homology to animal PRA1 and localize to the endoplasmic reticulum (ER) and/or endosomes. However, the exact role of these proteins remains to be fully characterized. In this study, the effect of AtPRA1.B6, a member of the AtPRA1 family, on the anterograde trafficking of proteins targeted to various endomembrane compartments was investigated. High levels of AtPRA1.B6 resulted in differential inhibition of coat protein complex II vesicle-mediated anterograde trafficking. The trafficking of the vacuolar proteins sporamin:GFP (for green fluorescent protein) and AALP:GFP, the secretory protein invertase:GFP, and the plasma membrane proteins PMP:GFP and H + -ATPase:GFP was inhibited in a dose-dependent manner, while the trafficking of the Golgi-localized proteins ST:GFP and KAM1(DC):mRFP was not affected. Conversely, in RNA interference plants displaying lower levels of AtPRA1.B6 transcripts, the trafficking efficiency of sporamin:GFP and AALP:GFP to the vacuole was increased. Localization and N-glycan pattern analyses of cargo proteins revealed that AtPRA1.B6-mediated inhibition of anterograde trafficking occurs at the ER. In addition, AtPRA1.B6 levels were controlled by cellular processes, including 26S proteasome-mediated proteolysis. Based on these results, we propose that AtPRA1. B6 is a negative regulator of coat protein complex II vesicle-mediated anterograde trafficking for a subset of proteins at the ER.

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“…Therefore, the perturbation of the BP-80 route to the vacuole can be monitored by following the relative abundance of the GFP-core on western-blot analyses. In addition, secretory GFP forms bearing a glycosylation peptide, glycosylated GFP, have been shown to be efficiently glycosylated in the plant ER (Batoko et al, 2000;Hanton et al, 2005). Therefore, they can be used as reliable markers to follow protein translocation into the ER and protein progression through the Golgi apparatus via endoglycosidase (ENDO-H) digestion (Hanton et al, 2007b).…”

Section: Gfp For Quantitative Analysesmentioning

confidence: 99%

Advances in Fluorescent Protein-Based Imaging for the Analysis of Plant Endomembranes

2008

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An exciting new era for live cell imaging of plant endomembranes was ushered in just over 10 years ago when Jim Haseloff and colleagues reported on the removal of a cryptic intron in the sequence of wildtype GFP for successful expression in plant cells (Haseloff et al., 1997). Haseloff's success was quickly welcomed by labs around the globe; by targeting GFP to secretory organelles, scientists could now bring to light the secret life of plant endomembranes. The plant endomembranes comprise several organelles functionally interlinked for the production and transport of secretory compounds, such as proteins, lipids, and sugars. Most of the secretory compounds are synthesized in the endoplasmic reticulum (ER) and then transported to the Golgi apparatus to be sorted for transport to distal compartments such as the plasma membrane and vacuoles. A forward transport of secretory molecules from the ER is counterbalanced by a retrograde flow from distal compartments that allows membrane homeostasis and communication with the cell's surroundings. Fluorescent protein technology applied to live cell imaging of plant endomembranes has aided immensely in providing subcellular markers for the study of the complex spatial and temporal relationships among secretory organelles. Live cell imaging is now moving forward to novel challenges. With the integration of genomic, transcriptomic, and proteomic techniques, we begin to collect data on the putative functions of plant genes; we need to understand the intricate relationships among thousands of proteins. To complete the puzzle, we must understand how the pieces fit together; we must define the functions of gene products. Important questions include: When are our proteins synthesized? Where are they targeted? With what elements do they interact? Advances in the development of optical imaging at the cellular level now offer the exciting opportunity to answer these questions.In this Update, we discuss several state-of-the-art applications of GFP imaging and how these techniques have been used to answer critical biological questions, with a focus on plant endomembrane trafficking.

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Diacidic Motifs Influence the Export of Transmembrane Proteins from the Endoplasmic Reticulum in Plant Cells

Cited by 98 publications

References 67 publications

De Novo Formation of Plant Endoplasmic Reticulum Export Sites Is Membrane Cargo Induced and Signal Mediated

De Novo Formation of Plant Endoplasmic Reticulum Export Sites Is Membrane Cargo Induced and Signal Mediated

An Arabidopsis Prenylated Rab Acceptor 1 Isoform, AtPRA1.B6, Displays Differential Inhibitory Effects on Anterograde Trafficking of Proteins at the Endoplasmic Reticulum

Advances in Fluorescent Protein-Based Imaging for the Analysis of Plant Endomembranes

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