Jürgen Denecke

Jürgen Denecke
University of Leeds · Centre for Plant Sciences

PhD in Chemistry

About

87
Publications
127,202
Reads
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5,535
Citations
Citations since 2017
4 Research Items
905 Citations
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2017201820192020202120222023050100150
2017201820192020202120222023050100150
2017201820192020202120222023050100150
Introduction
We study the secretory pathway, a group of membrane bound organelles that play key functions in virtually every process of eukaryotic life. Our research is mainly curiosity- and hypothesis-driven, and we use biochemical transport assays, cellular engineering, and in vivo imaging techniques to capture the exciting microcosmos of plant cells. More recently, we have become interested in harnessing the plant secretory pathway for the renewable production of food, energy and materials from plants.
Additional affiliations
January 1999 - present
University of Leeds
Position
  • Professor for Plant Cell Biology and Biotechnology
Description
  • We work on protein trafficking and organelle homeostasis in the secretory pathway. We also work on bio-fuel production, using starch crops such as potato as feedstock for the production of recombinant high value proteins and bioethanol.
September 1994 - December 1998
The University of York
Position
  • Lecturer
Description
  • It was at York where I established my own research laboratory, focussing on plant ER chaperones and protein trafficking through the secretory pathway
May 1991 - August 1994
Swedish University of Agricultural Sciences
Position
  • Senior Researcher
Description
  • Exploring the role of the secretory pathway in plant pathogen interactions
Education
October 1986 - May 1991
Ghent University
Field of study
  • Chemistry

Publications

Publications (87)
Article
Full-text available
Plant vacuolar sorting receptors (VSRs) display cytosolic Tyr motifs (YMPL) for clathrin-mediated anterograde transport to the prevacuolar compartment. Here, we show that the same motif is also required for VSR recycling. A Y612A point mutation in Arabidopsis thaliana VSR2 leads to a quantitative shift in VSR2 steady state levels from the prevacuol...
Article
Full-text available
To study protein secretion in plant cells, we established and evaluated a model system based on transient synthesis of heterologous proteins in tobacco protoplasts. We show that the nonsecretory enzymes phosphinothricin acetyl transferase, neomycin phosphotransferase II, and beta-glucuronidase are secreted when targeted to the lumen of the endoplas...
Article
Full-text available
COPII-coated vesicles, first identified in yeast and later characterized in mammalian cells, mediate protein export from the endoplasmic reticulum (ER) to the Golgi apparatus within the secretory pathway. In these organisms, the mechanism of vesicle formation is well understood, but the process of soluble cargo sorting has yet to be resolved. In pl...
Preprint
The K/HDEL receptor (ER retention defective 2 or ERD2) does not recycle between compartments when sorting ER chaperones, contrary to the favoured model. A conserved C-terminal di-leucine motif specifically prevents ERD2 Golgi-to-ER transport and is not required for ER export. The Golgi-retention mechanism strips Golgi-membranes of the GTPase ARF1 s...
Article
Full-text available
The plant Golgi apparatus is responsible for the processing of proteins received from the endoplasmic reticulum (ER) and their distribution to multiple destinations within the cell. Golgi matrix components, such as golgins, have been identified and suggested to function as putative tethering factors to mediate the physical connections between Golgi...
Article
Full-text available
Accumulation of soluble proteins in the endoplasmic reticulum (ER) of plants is mediated by a receptor termed ER RETENTION DEFECTIVE 2 (ERD2) or K/HDEL receptor. Using two gain-of-function assays and by complementing loss of function in Nicotiana benthamiana we discovered that compromising the lumenal N-terminus or the cytosolic C-terminus with flu...
Article
Due to the numerous roles plant vacuoles play in cell homeostasis, detoxification, and protein storage, the trafficking pathways to this organelle have been extensively studied. Recent evidence, however, suggests that our vision of transport to the vacuole is not as simple as previously imagined. Alternative routes have been identified and are bein...
Article
Full-text available
Soluble hydrolases represent the main proteins of lysosomes and vacuoles and are essential to sustain the lytic properties of these organelles typical for the eukaryotic organisms. The sorting of these proteins from ER residents and secreted proteins is controlled by highly specific receptors to avoid mislocalization and subsequent cellular damage....
Article
Abstract Transport of proteins via the secretory pathway is controlled by a combination of signal dependent cargo selection as well as unspecific bulk flow of membranes and aqueous lumen. Using the plant vacuolar sorting receptor as model for membrane spanning proteins, we have distinguished bulk flow from signal mediated protein targeting in biosy...
Article
Full-text available
The cycling of vacuolar sorting receptors (VSRs) between early and late secretory pathway compartments is regulated by signals in the cytosolic tail, but the exact pathway is controversial. Here, we show that receptor targeting in tobacco (Nicotiana tabacum) initially involves a canonical coat protein complex II-dependent endoplasmic reticulum-to-G...
Article
Here we examine the potential coupling between the synthesis of secretory proteins and the sensitivity of exocytosis to the concentration of free Ca(2+) in the cytosol ([Ca(2+)](i)) in plant cell. We therefore monitor in tobacco protoplasts the excursion of the membrane capacitance in response to an elevation of [Ca(2+)](i) as a measure for exocyto...
Article
Full-text available
Delivery of proteins to the lytic vacuole in plants is a complex cascade of selective interactions that specifically excludes residents of the endoplasmic reticulum and secreted proteins. Vacuolar transport must be highly efficient to avoid mistargeting of hydrolytic enzymes to locations where they could be harmful. While plant vacuolar sorting sig...
Article
Pentatricopeptide repeat (PPR) proteins belong to a family of approximately 450 members in Arabidopsis, of which few have been characterized. We identified loss of function alleles of SLO2, defective in a PPR protein belonging to the E+ subclass of the P-L-S subfamily. slo2 mutants are characterized by retarded leaf emergence, restricted root growt...
Article
Full-text available
Transient gene expression, in plant protoplasts or specific plant tissues, is a key technique in plant molecular cell biology, aimed at exploring gene products and their modifications to examine functional subdomains, their interactions with other biomolecules, and their subcellular localization. Here, we highlight some of the major advantages and...
Article
GTPases of the Rab5 and Rab7 families were shown to control vacuolar sorting but their specific subcellular localization is controversial in plants. Here, we show that both the canonical as well as the plant-specific Rab5 reside at the newly discovered 'late prevacuolar compartment' (LPVC) while Rab7 partitions to the vacuolar membrane when express...
Article
AbstractGTPases of the Rab5 and Rab7 families were shown to control vacuolar sorting but their specific subcellular localization is controversial in plants. Here, we show that both the canonical as well as the plant‐specific Rab5 reside at the newly discovered ‘late prevacuolar compartment’ (LPVC) while Rab7 partitions to the vacuolar membrane when...
Article
Full-text available
We tested if different classes of vacuolar cargo reach the vacuole via distinct mechanisms by interference at multiple steps along the transport route. We show that nucleotide-free mutants of low molecular weight GTPases, including Rab11, the Rab5 members Rha1 and Ara6, and the tonoplast-resident Rab7, caused induced secretion of both lytic and sto...
Article
Full-text available
Enrique Rojo and Jurgen Denecke*Departamento de Gene ´tica Molecular de Plantas, Centro Nacional de Biotecnologia-Consejo Superior deInvestigaciones Cienti´ficas, E–28049 Madrid, Spain (E.R.); and Centre for Plant Sciences, Faculty of BiologicalSciences, The University of Leeds, Leeds LS2 9JT, United Kingdom (J.D.)The secretory pathway of eukaryotic...
Article
Overexpression of the Golgi and endoplasmic reticulum (ER) syntaxins SYP31 and SYP81 strongly inhibits constitutive secretion. By comparing the secreted reporter alpha-amylase with the ER-retained reporter alpha-amylase-HDEL, it was concluded that SYP81 overexpression inhibits both retrograde and anterograde transport, while SYP31 overexpression ma...
Article
The secretory pathway of eukaryotic cells comprises a network of organelles that connects three large membranes, the plasma membrane, the vacuole and the endoplasmic reticulum. The Golgi apparatus and the various post-Golgi organelles that control vacuolar sorting, secretion and endocytosis can be regarded as intermediate organelles of the endocyti...
Article
Full-text available
Tomato spotted wilt virus (TSWV) particles are spherical and enveloped, an uncommon feature among plant infecting viruses. Previous studies have shown that virus particle formation involves the enwrapment of ribonucleoproteins with viral glycoprotein containing Golgi stacks. In this study, the localization and behaviour of the viral glycoproteins G...
Article
The endoplasmic reticulum (ER) chaperone binding protein (BiP) binds exposed hydrophobic regions of misfolded proteins. Cycles of ATP hydrolysis and nucleotide exchange on the ATPase domain were shown to regulate the function of the ligand-binding domain in vitro. Here we show that ATPase mutants of BiP with defective ATP-hydrolysis (T46G) or ATP-b...
Article
Full-text available
Golgi-mediated transport to the lytic vacuole involves passage through the prevacuolar compartment (PVC), but little is known about how vacuolar proteins exit the PVC. We show that this last step is inhibited by overexpression of Arabidopsis thaliana syntaxin PEP12/SYP21, causing an accumulation of soluble and membrane cargo and the plant vacuolar...
Article
Full-text available
Although signals for vacuolar sorting of soluble proteins are well described, we have yet to learn how the plant vacuolar sorting receptor BP80 reaches its correct destination and recycles. To shed light on receptor targeting, we used an in vivo competition assay in which a truncated receptor (green fluorescent protein-BP80) specifically competes w...
Article
The main resident proteins of the endoplasmic reticulum (ER) collaborate to ensure that newly synthesized secretory proteins acquire their correct conformation. Most ER residents are therefore, directly or indirectly, folding helpers and controllers of the quality of newly synthesized secretory polypeptides. Genetic approaches have revealed that th...
Article
Full-text available
Quality control in the endoplasmic reticulum (ER) prevents the arrival of incorrectly or incompletely folded proteins at their final destinations and targets permanently misfolded proteins for degradation. Such proteins have a high affinity for the ER chaperone BiP and are finally degraded via retrograde translocation from the ER lumen back to the...
Article
Full-text available
KM+, a mannose-binding lectin present in the seeds of Artocarpus integrifolia, has interesting biological properties and potential pharmaceutical use [A. Panunto-Castelo, M.A. Souza, M.C. Roque-Barreira, J.S. Silva, KM(+), a lectin from Artocarpus integrifolia, induces IL-12 p40 production by macrophages and switches from type 2 to type 1 cell-medi...
Article
Full-text available
We have characterized the requirements to inhibit the function of the plant vacuolar sorting receptor BP80 in vivo and gained insight into the crucial role of receptor recycling between the prevacuolar compartment and the Golgi apparatus. The drug wortmannin interferes with the BP80-mediated route to the vacuole and induces hypersecretion of a solu...
Article
Full-text available
In contrast with animals, plant cells contain multiple mobile Golgi stacks distributed over the entire cytoplasm. However, the distribution and dynamics of protein export sites on the plant endoplasmic reticulum (ER) surface have yet to be characterized. A widely accepted model for ER-to-Golgi transport is based on the sequential action of COPII an...
Article
Full-text available
We have assessed the ability of the plant secretory pathway to handle the expression of complex heterologous proteins by investigating the fate of a hybrid immunoglobulin A/G in tobacco cells. Although plant cells can express large amounts of the antibody, a relevant proportion is normally lost to vacuolar sorting and degradation. Here we show that...
Article
Full-text available
We have studied the transport of soluble cargo molecules by inhibiting specific transport steps to and from the Golgi apparatus. Inhibition of export from the Golgi via coexpression of a dominant-negative GTP-restricted ARF1 mutant (Q71L) inhibits the secretion of alpha-amylase and simultaneously induces the secretion of the vacuolar protein phytep...
Article
Full-text available
Quality control in the secretory pathway is a fundamental step in preventing deleterious effects that may arise by the release of malfolded proteins into the cell or apoplast. Our aims were to visualise and analyse the disposal route followed by aberrant proteins within a plant cell in vivo using fluorescent protein technology. A green fluorescent...
Article
Full-text available
The function of the secretory pathway is dependent on multiple protein-protein interactions at various stages. Currently, such interactions are mainly studied using physical methods that document direct contact or affinity in vitro. The development of vital fluorescence imaging as well as quantitative protein transport assays opens up the implement...
Article
Full-text available
Protein sorting to plant vacuoles is known to be dependent on a considerable variety of protein motifs recognized by a family of sorting receptors. This can involve either traffic from the endoplasmic reticulum (ER) through the Golgi apparatus or direct ER-to-vacuole transport. Barley aspartic protease (Phytepsin) was shown previously to reach the...
Chapter
The plant endoplasmic reticulum is responsible for the synthesis and often storage of a large group of proteins and lipids that enter the secretory pathway. This multifunctional organelle, which also represents one of the calcium storage compartments in plant cells, has currently received considerable interest in the research community because of f...
Article
The secretory pathway of plants is a network of organelles that communicate via vesicle transport. This process involves budding on donor membranes followed by their targeting to, recognition by and fusion with the acceptor membrane. Protein sorting through the plant secretory pathway is a process that requires the specific recognition of signals b...
Article
Full-text available
Coat protein (COP)-coated vesicles have been shown to mediate protein transport through early steps of the secretory pathway in yeast and mammalian cells. Here, we attempt to elucidate their role in vesicular trafficking of plant cells, using a combined biochemical and ultrastructural approach. Immunogold labeling of cryosections revealed that COPI...
Article
Full-text available
We have studied the possible mechanisms of endoplasmic reticulum (ER) export and retention by using natural residents of the plant ER. Under normal physiological conditions, calreticulin and the lumenal binding protein (BiP) are efficiently retained in the ER. When the ER retention signal is removed, truncated calreticulin is much more rapidly secr...
Article
Full-text available
When it is attacked by a pathogen, a plant produces a range of defense-related proteins. Many of these are synthesized by the rough endoplasmic reticulum (RER) to be secreted from the cell or deposited in vacuoles. Genes encoding endoplasmic reticulum (ER)-resident chaperones, such as the lumenal binding protein (BiP), are also induced under these...
Data
Full-text available
We have studied the possible mechanisms of endoplasmic reticulum (ER) export and retention by using natural resi-dents of the plant ER. Under normal physiological conditions, calreticulin and the lumenal binding protein (BiP) are effi-ciently retained in the ER. When the ER retention signal is removed, truncated calreticulin is much more rapidly se...
Article
Full-text available
To study the role of the lumenal binding protein (BiP) in the transport and secretion of proteins, we have produced plants with altered BiP levels. Transgenic plants overexpressing BiP showed dramatically increased BiP mRNA levels but only a modest increase in BiP protein levels. The presence of degradation products in BiP overproducers suggests a...
Article
It has been proposed that the two closely related proteins calreticulin and calnexin may act as molecular chaperones. However, calreticulin has also been implicated in a wide variety of seemingly unrelated cellular processes, which has led to considerable controversy about its function. There have been a number of recent reports on the specific pro...
Article
Full-text available
BiP is found in association with calreticulin, both in the presence and absence of endoplasmic reticulum stress. Although the BiP-calreticulin complex can be disrupted by ATP, several properties suggest that the calreticulin associated with BiP is neither unfolded nor partially or improperly folded. (1) The complex is stable in vivo and does not di...
Data
BiP is found in association with calreticulin, both in the presence and absence of endoplasmic reticulum stress. Al-though the BiP–calreticulin complex can be disrupted by ATP, several properties suggest that the calreticulin associated with BiP is neither unfolded nor partially or improperly folded. (1) The complex is stable in vivo and does not d...
Article
The virulence of the plant pathogen Erwinia carotovora subsp. carotovora is dependent on the production and secretion of a large variety of plant cell wall-degrading enzymes, including several pectinases and cellulases. Treatment of tobacco plants with culture filtrates (CFs) from the pathogen (containing the secreted cell wall-degrading enzymes) i...
Chapter
Many steps in the intracellular transport of proteins are facilitated by microvesicles (i.e vesicles with a diameter of less than 100 nm) which have a protein coat on their cytosolic surface. Morphologically speaking coated vesicles belong to one of two major classes: clathrin coated vesicles (CCV), which in transverse section have regular hornlike...
Article
Full-text available
Infection of tobacco plants with the plant pathogenic bacterium Erwinia carotovora subsp. carotovora or treatment of plants with Erwinia-derived elicitor preparations leads to the induction of a number of genes thought to play a role in plant defense response to pathogens. In order to determine the role of salicylic acid (SA) in the induction of th...
Article
This chapter discusses the use of protoplasts to study protein synthesis and transport by the plant endomembrane system. The endomembrane system comprises a series of compartments, the majority of which are the endoplasmic reticulum (ER), the Golgi complex, and the vacuole. These structures are interconnected by vesicular traffic. This network of c...
Article
Full-text available
The analysis of protein sorting signals responsible for the retention of reticuloplasmins (RPLs), a group of soluble proteins that reside in the lumen of the endoplasmic reticulum (ER), has revealed a structural similarity between mammalian and plant ER retention signals. We present evidence that the corresponding epitope is conserved in a vast fam...
Article
The analysis of protein sorting signals responsible for the retention of reticuloplasmins (RPLs), a group of soluble proteins that reside in the lumen of the endoplasmic reticulum (ER), has revealed a structural similarity between mammalian and plant ER retention signals. We present evidence that the corresponding epitope is conserved in a vast fam...
Article
The endoplasmic reticulum (ER) is the port of entry of the protein secretory pathway. Proteins destined for the cell wall, the vacuole or for the other compartments of the endomembrane system are first inserted into the ER and then transported to the Golgi complex en route to their final destinations. The ER is the compartment where newly-synthesiz...