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Wang XL, Hu ZY, You CX, Kong XZ, Shi XP. Subcellular localization and vacuolar targeting of sorbitol dehydrogenase in apple seed. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2013; 210:36-45. [PMID: 23849111 DOI: 10.1016/j.plantsci.2013.04.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 04/21/2013] [Accepted: 04/24/2013] [Indexed: 06/02/2023]
Abstract
Sorbitol is the primary photosynthate and translocated carbohydrate in fruit trees of the Rosaceae family. NAD(+)-dependent sorbitol dehydrogenase (NAD-SDH, EC 1.1.1.14), which mainly catalyzes the oxidation of sorbitol to fructose, plays a key role in regulating sink strength in apple. In this study, we found that apple NAD-SDH was ubiquitously distributed in epidermis, parenchyma, and vascular bundle in developing cotyledon. NAD-SDH was localized in the cytosol, the membranes of endoplasmic reticulum and vesicles, and the vacuolar lumen in the cotyledon at the middle stage of seed development. In contrast, NAD-SDH was mainly distributed in the protein storage vacuoles in cotyledon at the late stage of seed development. Sequence analysis revealed there is a putative signal peptide (SP), also being predicated to be a transmembrane domain, in the middle of proteins of apple NAD-SDH isoforms. To investigate whether the putative internal SP functions in the vacuolar targeting of NAD-SDH, we analyzed the localization of the SP-deletion mutants of MdSDH5 and MdSDH6 (two NAD-SDH isoforms in apple) by the transient expression system in Arabidopsis protoplasts. MdSDH5 and MdSDH6 were not localized in the vacuoles after their SPs were deleted, suggesting the internal SP functions in the vacuolar targeting of apple NAD-SDH.
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Affiliation(s)
- Xiu-Ling Wang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian 271018, China.
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Feeney M, Frigerio L, Cui Y, Menassa R. Following vegetative to embryonic cellular changes in leaves of Arabidopsis overexpressing LEAFY COTYLEDON2. PLANT PHYSIOLOGY 2013; 162:1881-96. [PMID: 23780897 PMCID: PMC3729768 DOI: 10.1104/pp.113.220996] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 06/06/2013] [Indexed: 05/21/2023]
Abstract
Embryogenesis in flowering plants is controlled by a complex interplay of genetic, biochemical, and physiological regulators. LEAFY COTYLEDON2 (LEC2) is among a small number of key transcriptional regulators that are known to play important roles in controlling major events during the maturation stage of embryogenesis, notably, the synthesis and accumulation of storage reserves. LEC2 overexpression causes vegetative tissues to change their developmental fate to an embryonic state; however, little information exists about the cellular changes that take place. We show that LEC2 alters leaf morphology and anatomy and causes embryogenic structures to form subcellularly in leaves of Arabidopsis (Arabidopsis thaliana). Chloroplasts accumulate more starch, the cytoplasm fills with oil bodies, and lytic vacuoles (LVs) appear smaller in size and accumulate protein deposits. Because LEC2 is responsible for activating the synthesis of seed storage proteins (SSPs) during seed development, SSP accumulation was investigated in leaves. The major Arabidopsis SSP families were shown to accumulate within small leaf vacuoles. By exploiting the developmental and tissue-specific localization of two tonoplast intrinsic protein isoforms, the small leaf vacuoles were identified as protein storage vacuoles (PSVs). Confocal analyses of leaf vacuoles expressing fluorescently labeled tonoplast intrinsic protein isoforms reveal an altered tonoplast morphology resembling an amalgamation of a LV and PSV. Results suggest that as the LV transitions to a PSV, the tonoplast remodels before the large vacuole lumen is replaced by smaller PSVs. Finally, using vegetative and seed markers to monitor the transition, we show that LEC2 induces a reprogramming of leaf development.
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Yuen CCY, Christopher DA. The group IV-A cyclic nucleotide-gated channels, CNGC19 and CNGC20, localize to the vacuole membrane in Arabidopsis thaliana. AOB PLANTS 2013. [PMCID: PMC4455320 DOI: 10.1093/aobpla/plt012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The cyclic nucleotide-gated channels, CNGC19 and CNGC20, are the sole members of the highly isolated evolutionary group IV-A in Arabidopsis plants. Prior studies have shown that the expression of both CNGC19 and CNGC20 genes are induced by salinity and biotic stress. In this report, CNGC19 and CNGC20 were determined to localize to the vacuolar membrane. Co-expression of CNGC19 and CNGC20 increased the efficiency of vacuolar localization. CNGC19 and CNGC20 are, therefore, vacuolar membrane channels that are hypothesized to mediate plant response to salinity and biotic stress. Plant cyclic nucleotide-gated channels (CNGCs) are implicated in the uptake of both essential and toxic cations, Ca2+ signalling, and responses to biotic and abiotic stress. The 20 CNGC paralogues of Arabidopsis are divided into five evolutionary groups. Group IV-A is highly isolated and consists only of two closely spaced genes, CNGC19 and CNGC20. Prior studies have shown that both genes are induced by salinity and biotic stress. A unique feature of CNGC19 and CNGC20 is their long hydrophilic N-termini. To determine the subcellular locations of CNGC19 and CNGC20, partial and full-length fusions to GFP(S65T) were generated. Translational fusions of the N-termini of CNGC19 (residues 1–171) and CNGC20 (residues 1–200) to GFP(S65T) were targeted to punctate structures when transiently expressed in leaf protoplasts. In the case of CNGC20, but not CNGC19, the punctate structures were co-labelled with a marker for the Golgi. The full-length CNGC19-GFP fusion co-localized with markers for the vacuole membrane (αTIP- and γTIP-mCherry). Vacuole membrane labelling by the full-length CNGC20-GFP fusion was also observed, but the signal was weak and accompanied by numerous punctate signals that did not co-localize with αTIP- or γTIP-mCherry. These punctate structures diminished, and localization of full-length CNGC20-GFP to the vacuole increased, when it was co-expressed with the full-length CNGC19-mCherry. Vacuole membrane labelling was also detected in planta via immunoelectron microscopy using a CNGC20-antiserum on cryopreserved ultrathin sections of roots. We hypothesize that the role of group IV-A CNGCs is to mediate the movement of cations between the central vacuole and the cytosol in response to certain types of abiotic and biotic stress.
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54
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Xiang L, Etxeberria E, den Ende W. Vacuolar protein sorting mechanisms in plants. FEBS J 2013; 280:979-93. [DOI: 10.1111/febs.12092] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2012] [Revised: 11/08/2012] [Accepted: 12/11/2012] [Indexed: 01/12/2023]
Affiliation(s)
- Li Xiang
- Laboratory of Molecular Plant Biology KU Leuven Belgium
| | - Ed Etxeberria
- Horticulture Department Citrus Research and Education Center University of Florida Lake Alfred FL USA
| | - Wim den Ende
- Laboratory of Molecular Plant Biology KU Leuven Belgium
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Seidel T, Siek M, Marg B, Dietz KJ. Energization of vacuolar transport in plant cells and its significance under stress. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 304:57-131. [PMID: 23809435 DOI: 10.1016/b978-0-12-407696-9.00002-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The plant vacuole is of prime importance in buffering environmental perturbations and in coping with abiotic stress caused by, for example, drought, salinity, cold, or UV. The large volume, the efficient integration in anterograde and retrograde vesicular trafficking, and the dynamic equipment with tonoplast transporters enable the vacuole to fulfill indispensible functions in cell biology, for example, transient and permanent storage, detoxification, recycling, pH and redox homeostasis, cell expansion, biotic defence, and cell death. This review first focuses on endomembrane dynamics and then summarizes the functions, assembly, and regulation of secretory and vacuolar proton pumps: (i) the vacuolar H(+)-ATPase (V-ATPase) which represents a multimeric complex of approximately 800 kDa, (ii) the vacuolar H(+)-pyrophosphatase, and (iii) the plasma membrane H(+)-ATPase. These primary proton pumps regulate the cytosolic pH and provide the driving force for secondary active transport. Carriers and ion channels modulate the proton motif force and catalyze uptake and vacuolar compartmentation of solutes and deposition of xenobiotics or secondary compounds such as flavonoids. ABC-type transporters directly energized by MgATP complement the transport portfolio that realizes the multiple functions in stress tolerance of plants.
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Affiliation(s)
- Thorsten Seidel
- Biochemistry and Physiology of Plants, Faculty of Biology, Bielefeld University, Bielefeld, Germany.
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Rivera-Serrano EE, Rodriguez-Welsh MF, Hicks GR, Rojas-Pierce M. A small molecule inhibitor partitions two distinct pathways for trafficking of tonoplast intrinsic proteins in Arabidopsis. PLoS One 2012; 7:e44735. [PMID: 22957103 PMCID: PMC3434187 DOI: 10.1371/journal.pone.0044735] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2012] [Accepted: 08/07/2012] [Indexed: 01/26/2023] Open
Abstract
Tonoplast intrinsic proteins (TIPs) facilitate the membrane transport of water and other small molecules across the plant vacuolar membrane, and members of this family are expressed in specific developmental stages and tissue types. Delivery of TIP proteins to the tonoplast is thought to occur by vesicle–mediated traffic from the endoplasmic reticulum to the vacuole, and at least two pathways have been proposed, one that is Golgi-dependent and another that is Golgi-independent. However, the mechanisms for trafficking of vacuolar membrane proteins to the tonoplast remain poorly understood. Here we describe a chemical genetic approach to unravel the mechanisms of TIP protein targeting to the vacuole in Arabidopsis seedlings. We show that members of the TIP family are targeted to the vacuole via at least two distinct pathways, and we characterize the bioactivity of a novel inhibitor that can differentiate between them. We demonstrate that, unlike for TIP1;1, trafficking of markers for TIP3;1 and TIP2;1 is insensitive to Brefeldin A in Arabidopsis hypocotyls. Using a chemical inhibitor that may target this BFA-insensitive pathway for membrane proteins, we show that inhibition of this pathway results in impaired root hair growth and enhanced vacuolar targeting of the auxin efflux carrier PIN2 in the dark. Our results indicate that the vacuolar targeting of PIN2 and the BFA-insensitive pathway for tonoplast proteins may be mediated in part by common mechanisms.
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Affiliation(s)
- Efrain E. Rivera-Serrano
- Department of Plant Biology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Maria F. Rodriguez-Welsh
- Department of Plant Biology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Glenn R. Hicks
- Department of Botany and Plant Sciences, University of California Riverside, Riverside, California, United States of America
- Center for Plant Cell Biology, University of California Riverside, Riverside, California, United States of America
| | - Marcela Rojas-Pierce
- Department of Plant Biology, North Carolina State University, Raleigh, North Carolina, United States of America
- * E-mail:
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Petricka JJ, Schauer MA, Megraw M, Breakfield NW, Thompson JW, Georgiev S, Soderblom EJ, Ohler U, Moseley MA, Grossniklaus U, Benfey PN. The protein expression landscape of the Arabidopsis root. Proc Natl Acad Sci U S A 2012. [PMID: 22447775 DOI: 10.1073/pnas,0.1202546109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023] Open
Abstract
Because proteins are the major functional components of cells, knowledge of their cellular localization is crucial to gaining an understanding of the biology of multicellular organisms. We have generated a protein expression map of the Arabidopsis root providing the identity and cell type-specific localization of nearly 2,000 proteins. Grouping proteins into functional categories revealed unique cellular functions and identified cell type-specific biomarkers. Cellular colocalization provided support for numerous protein-protein interactions. With a binary comparison, we found that RNA and protein expression profiles are weakly correlated. We then performed peak integration at cell type-specific resolution and found an improved correlation with transcriptome data using continuous values. We performed GeLC-MS/MS (in-gel tryptic digestion followed by liquid chromatography-tandem mass spectrometry) proteomic experiments on mutants with ectopic and no root hairs, providing complementary proteomic data. Finally, among our root hair-specific proteins we identified two unique regulators of root hair development.
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Affiliation(s)
- Jalean J Petricka
- Department of Biology, Duke Center for Systems Biology, and Institute for Genome Sciences and Policy, Duke University, Durham, NC 27708, USA
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Ibl V, Stoger E. The formation, function and fate of protein storage compartments in seeds. PROTOPLASMA 2012; 249:379-92. [PMID: 21614590 DOI: 10.1007/s00709-011-0288-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Accepted: 05/12/2011] [Indexed: 05/07/2023]
Abstract
Seed storage proteins (SSPs) have been studied for more than 250 years because of their nutritional value and their impact on the use of grain in food processing. More recently, the use of seeds for the production of recombinant proteins has rekindled interest in the behavior of SSPs and the question how they are able to accumulate as stable storage reserves. Seed cells produce vast amounts of SSPs with different subcellular destinations creating an enormous logistic challenge for the endomembrane system. Seed cells contain several different storage organelles including the complex and dynamic protein storage vacuoles (PSVs) and other protein bodies (PBs) derived from the endoplasmic reticulum (ER). Storage proteins destined for the PSV may pass through or bypass the Golgi, using different vesicles that follow different routes through the cell. In addition, trafficking may depend on the plant species, tissue and developmental stage, showing that the endomembrane system is capable of massive reorganization. Some SSPs contain sorting signals or interact with membranes or with other proteins en route in order to reach their destination. The ability of SSPs to form aggregates is particularly important in the formation or ER-derived PBs, a mechanism that occurs naturally in response to overloading with proteins that cannot be transported and that can be used to induce artificial storage bodies in vegetative tissues. In this review, we summarize recent findings that provide insight into the formation, function, and fate of storage organelles and describe tools that can be used to study them.
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Affiliation(s)
- Verena Ibl
- Department for Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190, Vienna, Austria
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59
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Abstract
Because proteins are the major functional components of cells, knowledge of their cellular localization is crucial to gaining an understanding of the biology of multicellular organisms. We have generated a protein expression map of the Arabidopsis root providing the identity and cell type-specific localization of nearly 2,000 proteins. Grouping proteins into functional categories revealed unique cellular functions and identified cell type-specific biomarkers. Cellular colocalization provided support for numerous protein-protein interactions. With a binary comparison, we found that RNA and protein expression profiles are weakly correlated. We then performed peak integration at cell type-specific resolution and found an improved correlation with transcriptome data using continuous values. We performed GeLC-MS/MS (in-gel tryptic digestion followed by liquid chromatography-tandem mass spectrometry) proteomic experiments on mutants with ectopic and no root hairs, providing complementary proteomic data. Finally, among our root hair-specific proteins we identified two unique regulators of root hair development.
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60
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Wang J, Tse YC, Hinz G, Robinson DG, Jiang L. Storage globulins pass through the Golgi apparatus and multivesicular bodies in the absence of dense vesicle formation during early stages of cotyledon development in mung bean. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:1367-80. [PMID: 22143915 PMCID: PMC3276096 DOI: 10.1093/jxb/err366] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
During seed development and maturation, large amounts of storage proteins are synthesized and deposited in protein storage vacuoles (PSVs). Multiple mechanisms have been proposed to be responsible for transporting storage proteins to PSVs in developing seeds. In this study, a specific antibody was raised against the mung bean (Vigna radiata) seed storage protein 8S globulin and its deposition was followed via immunogold electron microscopy in developing mung bean cotyledons. It is demonstrated that non-aggregated 8S globulins are present in multivesicular bodies (MVBs) in early stages of cotyledon development where neither dense vesicles (DVs) nor a PSV were recognizable. However, at later stages of cotyledon development, condensed globulins were visible in both DVs and distinct MVBs with a novel form of partitioning, with the internal vesicles being pushed to one sector of this organelle. These distinct MVBs were no longer sensitive to wortmannin. This study thus indicates a possible role for MVBs in transporting storage proteins to PSVs during the early stage of seed development prior to the involvement of DVs. In addition, wortmannin treatment is shown to induce DVs to form aggregates and to fuse with the plasma membrane.
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Affiliation(s)
- Junqi Wang
- School of Life Sciences, Centre for Cell and Developmental Biology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Yu Chung Tse
- School of Life Sciences, Centre for Cell and Developmental Biology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Giselbert Hinz
- Department of Plant Cell Biology, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - David G. Robinson
- Department of Plant Cell Biology, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Liwen Jiang
- School of Life Sciences, Centre for Cell and Developmental Biology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
- To whom correspondence should be addressed. E-mail:
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61
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Abstract
Protein turnover is fundamental both for development and cellular homeostasis. The mechanisms responsible for the turnover of integral membrane proteins in plant cells are however still largely unknown. Recently, considerable attention has been devoted to the degradation of plasma membrane proteins. We have now studied the turnover of a tonoplast protein, the potassium channel TPK1, in fully differentiated Arabidopsis leaf cells and showed that its degradation occurs upon internalization into the vacuole. Here, we discuss the possible mechanisms and triggering events involved.
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Jørgensen M, Stensballe A, Welinder KG. Extensive post-translational processing of potato tuber storage proteins and vacuolar targeting. FEBS J 2011; 278:4070-87. [PMID: 21851554 DOI: 10.1111/j.1742-4658.2011.08311.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Potato tuber storage proteins were obtained from vacuoles isolated from field-grown starch potato tubers cv. Kuras. Vacuole sap proteins fractionated by gel filtration were studied by mass spectrometric analyses of trypsin and chymotrypsin digestions. The tuber vacuole appears to be a typical protein storage vacuole absent of proteolytic and glycolytic enzymes. The major soluble storage proteins included 28 Kunitz protease inhibitors, nine protease inhibitors 1, eight protease inhibitors 2, two carboxypeptidase inhibitors, eight patatins and five lipoxygenases (lox), which all showed cultivar-specific sequence variations. These proteins, except for lox, have typical endoplasmic reticulum (ER) signal peptides and putative vacuolar sorting determinants of either the sequence or structure specific type or the C-terminal type, or both. Unexpectedly, sap protein variants imported via the ER showed multiple molecular forms because of extensive and unspecific proteolytic cleavage of exposed N- and C-terminal propeptides and surface loops, in spite of the abundance of protease inhibitors. Some propeptides are potential novel vacuolar targeting peptides. In the insoluble vacuole fraction two variants of phytepsin (aspartate protease) were identified. These are most probably the processing enzymes of potato tuber vacuolar proteins. Database Proteome data have been submitted to the PRIDE database under accession number 17707.
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Affiliation(s)
- Malene Jørgensen
- Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Aalborg, Denmark
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63
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Distinct Lytic Vacuolar Compartments are Embedded Inside the Protein Storage Vacuole of Dry and Germinating Arabidopsis thaliana Seeds. ACTA ACUST UNITED AC 2011; 52:1142-52. [DOI: 10.1093/pcp/pcr065] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Park M, Jürgens G. Membrane traffic and fusion at post-Golgi compartments. FRONTIERS IN PLANT SCIENCE 2011; 2:111. [PMID: 22645561 PMCID: PMC3355779 DOI: 10.3389/fpls.2011.00111] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 12/19/2011] [Indexed: 05/18/2023]
Abstract
Complete sequencing of the Arabidopsis genome a decade ago has facilitated the functional analysis of various biological processes including membrane traffic by which many proteins are delivered to their sites of action and turnover. In particular, membrane traffic between post-Golgi compartments plays an important role in cell signaling, taking care of receptor-ligand interaction and inactivation, which requires secretion, endocytosis, and recycling or targeting to the vacuole for degradation. Here, we discuss recent studies that address the identity of post-Golgi compartments, the machinery involved in traffic and fusion or functionally characterized cargo proteins that are delivered to or pass through post-Golgi compartments. We also provide an outlook on future challenges in this area of research.
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Affiliation(s)
- Misoon Park
- Entwicklungsgenetik, Zentrum für Molekularbiologie der Pflanzen, University of TübingenTübingen, Germany
| | - Gerd Jürgens
- Entwicklungsgenetik, Zentrum für Molekularbiologie der Pflanzen, University of TübingenTübingen, Germany
- *Correspondence: Gerd Jürgens, Entwicklungsgenetik, Zentrum für Molekularbiologie der Pflanzen, University of Tübingen, Auf der Morgenstelle 3, 72076 Tübingen, Germany. e-mail:
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