The plant ER-Golgi interface: a highly structured and dynamic membrane complex. J Exp Bot 58: 49-64
ABSTRACT As compared with other eukaryotic cells, plants have developed an endoplasmic reticulum (ER)-Golgi interface with very specific structural characteristics. ER to Golgi and Golgi to ER transport appear not to be dependent on the cytoskeleton, and ER export sites have been found closely associated with Golgi bodies to constitute entire mobile units. However, the molecular machinery involved in membrane trafficking seems to be relatively conserved among eukaryotes. Therefore, a challenge for plant scientists is to determine how these molecular machineries work in a different structural and dynamic organization. This review will focus on some aspects of membrane dynamics that involve coat proteins, SNAREs (soluble N-ethylmaleimide-sensitive factor attachment receptor proteins), lipids, and lipid-interacting proteins.
- SourceAvailable from: Jean-William Dupuy
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- "SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins are components of the molecular machinery involved in the vesicular secretory pathway of eukaryotic cells. They contribute to the fusion of membranes and are essential for numerous plant physiological functions (Lipka et al., 2007; Moreau et al., 2007; Bassham et al., 2008; Kim and Brandizzi, 2012). Most of them have a C-terminal (C-ter) transmembrane domain and at least one coil-coiled domain (~70 amino acids), also called the SNARE domain, in the cytosolic part of the protein. "
ABSTRACT: The SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins are critical for the function of the secretory pathway. The SNARE Memb11 is involved in membrane trafficking at the ER-Golgi interface. The aim of the work was to decipher molecular mechanisms acting in Memb11-mediated ER-Golgi traffic. In mammalian cells, the orthologue of Memb11 (membrin) is potentially involved in the recruitment of the GTPase Arf1 at the Golgi membrane. However molecular mechanisms associated to Memb11 remain unknown in plants. Memb11 was detected mainly at the cis-Golgi and co-immunoprecipitated with Arf1, suggesting that Arf1 may interact with Memb11. This interaction of Memb11 with Arf1 at the Golgi was confirmed by in vivo BiFC (Bimolecular Fluorescence Complementation) experiments. This interaction was found to be specific to Memb11 as compared to either Memb12 or Sec22. Using a structural bioinformatic approach, several sequences in the N-ter part of Memb11 were hypothesized to be critical for this interaction and were tested by BiFC on corresponding mutants. Finally, by using both in vitro and in vivo approaches, we determined that only the GDP-bound form of Arf1 interacts with Memb11. Together, our results indicate that Memb11 interacts with the GDP-bound form of Arf1 in the Golgi apparatus. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: email@example.com.Journal of Experimental Botany 07/2015; DOI:10.1093/jxb/erv373 · 5.53 Impact Factor
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- "Additionally, the putative target of zma-miR482-5p was determined to be an ABA-responsive gene, rab15B, which encodes a dehydrin protein associated with water deficit in wheat (King et al., 1992; Hassan et al., 2014). Being a potential target of pab-miR3710, VAMP/SNARE-associated protein SEC22 was found to be related with cesium accumulation in Arabidopsis (Dräxl et al., 2013) and ER–Golgi membrane trafficking (Moreau et al., 2007). "
ABSTRACT: Hexaploid bread wheat (Triticum aestivum L.) is one of the major crops grown and consumed all over the world. Elevated soil-salinity causes reduction in crop yield and quality; therefore several strategies were developed to improve salt-tolerant cultivars. MicroRNAs (miRNAs), small and noncoding RNAs, regulate gene expression at post-transcriptional level and play important roles in stress tolerance. Here, we used a broad-range miRNA-microarray analysis to investigate the root-miRNA profiles of two cultivars, Bezostaja (sensitive) and Seri-82 (tolerant). A total of 44 differentially–regulated miRNAs were identified in the 8x15K array containing 11,862 plant miRNAs available in the database. Sixteen novel salt-responsive miRNAs were determined in wheat for the first time. The expression of three miRNAs (hvu-miR5049a, ppt-miR1074, and osa-miR444b.2) was up-regulated more than 260-fold in cv. Bezostaja upon salt stress. The target-gene analyses showed that several salt–stress-responsive miRNAs regulate mainly transcription factors such as bHLH135-like, AP2/ERBP, MADS-box and transporters. Gene-ontology searches for 565 putative salt-stress-responsive miRNA target-genes revealed 623 processes in ten different main topics such as metabolic process and response to stimuli. The genome-wide root miRNome study indicates salt-stress-responsive wheat miRNAs and the possible mechanisms behind the tolerance.Annals of Applied Biology 03/2015; DOI:10.1111/aab.12219 · 2.00 Impact Factor
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- "Technical advances by FIB/SEM analysis and subsequent 3-D reconstruction provides new insight into architecture of interphase dictyosomes and into formation of MVBs in the unicellular green alga Micrasterias. The most important new result is the 3-D visualization of a huge ER sheath at the trans-side of the dictyosomes which together with the common cis-Golgi associated ER system known from different plant cells (among others see Hawes and Satiat-Jeunemaitre (2005), Moreau et al. (2007)) almost entirely enwraps the dictyosomes in Micrasterias. Neither TEM serial sectioning nor electron tomography would be able to provide information on the magnitude of this ER envelope. "
ABSTRACT: In the present study we employ FIB/SEM tomography for analyzing 3-D architecture of dictyosomes and formation of multivesicular bodies (MVB) in high pressure frozen and cryo-substituted interphase cells of the green algal model system Micrasterias denticulata. The ability of FIB/SEM of milling very thin ‘slices’ (5–10 nm), viewing the block face and of capturing cytoplasmic volumes of several hundred μm3 provides new insight into the close spatial connection of the ER–Golgi machinery in an algal cell particularly in z-direction, complementary to informations obtained by TEM serial sectioning or electron tomography. Our FIB/SEM series and 3-D reconstructions show that interphase dictyosomes of Micrasterias are not only closely associated to an ER system at their cis-side which is common in various plant cells, but are surrounded by a huge “trans-ER” sheath leading to an almost complete enwrapping of dictyosomes by the ER. This is particularly interesting as the presence of a trans-dictyosomal ER system is well known from mammalian secretory cells but not from cells of higher plants to which the alga Micrasterias is closely related. In contrast to findings in plant storage tissue indicating that MVBs originate from the trans-Golgi network or its derivatives our investigations show that MVBs in Micrasterias are in direct spatial contact with both, trans-Golgi cisternae and the trans-ER sheath which provides evidence that both endomembrane compartments are involved in their formation.Journal of Structural Biology 10/2013; 184(2). DOI:10.1016/j.jsb.2013.10.003 · 3.23 Impact Factor