MAIGO2 Is Involved in Exit of Seed Storage Proteins from the Endoplasmic Reticulum in <i>Arabidopsis thaliana</i>

Li, Lixin; Shimada, Tomoo; Takahashi, Hideyuki; Ueda, Haruko; Fukao, Yoichiro; Kondo, Maki; Nishimura, Mikio; Hara‐Nishimura, Ikuko

doi:10.1105/tpc.106.046151

Cited by 80 publications

(114 citation statements)

References 49 publications

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“…An Arabidopsis thaliana mutant, maigo2 (mag2), accumulated the precursors of two major storage proteins, 2S albumin and 12S globulin, in dry seeds. MAG2 functions in the transport of storage protein precursors between the ER and Golgi apparatus in plants (Li et al 2006). A type I membrane protein, AtVSR1/AtELP, of Arabidopsis functions as a sorting receptor for storage proteins.…”

Section: Discussionmentioning

confidence: 99%

Gene-gene interactions between mutants that accumulate abnormally high amounts of proglutelin in rice seed

et al. 2010

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We had previously identified eight mutants, esp2 and g(G)lups1 to 7, which accumulated abnormally high amounts of proglutelin, the major storage protein in rice seeds. Analysis of their seed proteins by SDS-PAGE, their levels of the luminal chaperone BiP and gene-gene interactions indicated that these mutants fell into four classes. The most epistatic class consisted of esp2, which encodes a defective protein disulfide isomerase (PDI). A second class consisting of Glup1, glup2 and glup7 was hypostatic to esp2, and showed abnormally high levels of BiP, suggesting that maturation and export of proglutelins from the ER are inhibited in this class of mutants. The third class containing glup4, Glup5 and glup6 mutations was hypostatic to esp2, Glup1, glup2 and glup7. Since the glup4 allele encodes the small GTPase Rab5a, which participates in the trafficking of proglutelin from Golgi apparatus to the protein storage vacuole (PSV), this third class of mutants is likely affected in this process. Lastly, glup3, which encodes a vacuolar processing enzyme, which proteolytically processes proglutelin into acidic and basic subunits within the PSV, was hypostatic to the other mutants. Overall, these gene relationships are consistent with the sequential intracellular transport and processing of proglutelin and provide novel insights on the trafficking of proglutelin to the PSV.

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Section: Discussionmentioning

confidence: 99%

Gene-gene interactions between mutants that accumulate abnormally high amounts of proglutelin in rice seed

et al. 2010

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“…Plants can transport proteins from the ER into vacuoles both through Golgi-dependent and Golgi-independent pathways Li et al, 2006;Shimada et al, 2006;Fuji et al, 2007). Indeed, Teh and Moore (2007) reported that gnl1 mutants, which are allelic to ermo1 mutants, accumulate secretory GFP in the ER.…”

Section: Gnl1/ermo1 and Sec24a/ermo2 May Have Roles In Maintaining Ermentioning

confidence: 99%

GNOM-LIKE1/ERMO1 and SEC24a/ERMO2 Are Required for Maintenance of Endoplasmic Reticulum Morphology inArabidopsis thaliana

et al. 2009

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The endoplasmic reticulum (ER) is composed of tubules, sheets, and three-way junctions, resulting in a highly conserved polygonal network in all eukaryotes. The molecular mechanisms responsible for the organization of these structures are obscure. To identify novel factors responsible for ER morphology, we employed a forward genetic approach using a transgenic Arabidopsis thaliana plant (GFP-h) with fluorescently labeled ER. We isolated two mutants with defects in ER morphology and designated them endoplasmic reticulum morphology1 (ermo1) and ermo2. The cells of both mutants developed a number of ER-derived spherical bodies, ;1 mm in diameter, in addition to the typical polygonal network of ER.The spherical bodies were distributed throughout the ermo1 cells, while they formed a large aggregate in ermo2 cells. We identified the responsible gene for ermo1 to be GNOM-LIKE1 (GNL1) and the gene for ermo2 to be SEC24a. Homologs of both GNL1 and SEC24a are involved in membrane trafficking between the ER and Golgi in yeast and animal cells. Our findings, however, suggest that GNL1/ERMO1 and SEC24a/ERMO2 have a novel function in ER morphology in higher plants.

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“…The development of the vamp727 syp22 double mutant was arrested at a late step of embryogenesis, suggesting an essential function of the VAMP727 complex in normal seed maturation. The small PSVs or faulty processing of storage proteins are probably not alone responsible for the lethality because many mutants with similar phenotypes have been reported to be viable (Shimada et al, 2003a(Shimada et al, , 2003bLi et al, 2006;Shimada et al, 2006;Fuji et al, 2007;Tamura et al, 2007). There should be additional defects in the vamp727 syp22 mutant that severely affect the viability of seeds.…”

Section: Online)mentioning

confidence: 99%

A SNARE Complex Unique to Seed Plants Is Required for Protein Storage Vacuole Biogenesis and Seed Development ofArabidopsis thaliana

et al. 2008

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The SNARE complex is a key regulator of vesicular traffic, executing membrane fusion between transport vesicles or organelles and target membranes. A functional SNARE complex consists of four coiled-coil helical bundles, three of which are supplied by Q-SNAREs and another from an R-SNARE. Arabidopsis thaliana VAMP727 is an R-SNARE, with homologs only in seed plants. We have found that VAMP727 colocalizes with SYP22/ VAM3, a Q-SNARE, on a subpopulation of prevacuolar compartments/endosomes closely associated with the vacuolar membrane. Genetic and biochemical analyses, including examination of a synergistic interaction of vamp727 and syp22 mutations, histological examination of protein localization, and coimmunoprecipitation from Arabidopsis lysates indicate that VAMP727 forms a complex with SYP22, VTI11, and SYP51 and that this complex plays a crucial role in vacuolar transport, seed maturation, and vacuole biogenesis. We suggest that the VAMP727 complex mediates the membrane fusion between the prevacuolar compartment and the vacuole and that this process has evolved as an essential step for seed development.

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MAIGO2 Is Involved in Exit of Seed Storage Proteins from the Endoplasmic Reticulum in Arabidopsis thaliana

Cited by 80 publications

References 49 publications

Gene-gene interactions between mutants that accumulate abnormally high amounts of proglutelin in rice seed

Gene-gene interactions between mutants that accumulate abnormally high amounts of proglutelin in rice seed

GNOM-LIKE1/ERMO1 and SEC24a/ERMO2 Are Required for Maintenance of Endoplasmic Reticulum Morphology inArabidopsis thaliana

A SNARE Complex Unique to Seed Plants Is Required for Protein Storage Vacuole Biogenesis and Seed Development ofArabidopsis thaliana

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