scholarly journals TGN/EE SNARE protein SYP61 is ubiquitinated and required for carbon/nitrogen-nutrient responses in Arabidopsis

2020 ◽  
Author(s):  
Yoko Hasegawa ◽  
Thais Huarancca Reyes ◽  
Tomohiro Uemura ◽  
Akari Fujimaki ◽  
Yongming Luo ◽  
...  
Keyword(s):  
Membrane Trafficking ◽  
Critical Role ◽  
Snare Protein ◽  
Post Translational Modification ◽  
Cellular Processes ◽  
Protein Receptor ◽  
Sensitive Factor ◽  
Cargo Proteins ◽  
Golgi Network

AbstractUbiquitination is a post-translational modification with reversible attachment of the small protein ubiquitin, which is involved in numerous cellular processes including membrane trafficking. For example, ubiquitination of cargo proteins is known to regulate their subcellular dynamics, and plays important roles in plant growth and stress adaptation. However, the regulatory mechanism of the trafficking machinery components remains elusive. Here, we report Arabidopsis trans-Golgi network/early endosome (TGN/EE) localized soluble N-ethylmaleimide sensitive factor attachment protein receptor (SNARE) protein SYP61 as a novel ubiquitination target of a membrane localized ubiquitin ligase ATL31. SYP61 is a key component of membrane trafficking in Arabidopsis. SYP61 was ubiquitinated with K63-linked chain by ATL31 in vitro and in plants. The knockdown mutants of SYP61 were hypersensitive to the disrupted carbon (C)/nitrogen (N)-nutrient stress, suggesting its critical role in plant homeostasis in response to nutrients. We also found the ubiquitination status of SYP61 is affected by C/N-nutrient availability. These results provided possibility that ubiquitination of SNARE protein has important role in plant physiology.

scholarly journals Syntaxin 16’s Newly Deciphered Roles in Autophagy

Cells ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1655 ◽  
Author(s):  
Bor Luen Tang
Keyword(s):  
Membrane Trafficking ◽  
Functional Redundancy ◽  
Transport Processes ◽  
Snare Complex ◽  
Dual Roles ◽  
Trans Golgi Network ◽  
Protein Receptor ◽  
Sensitive Factor ◽  
Golgi Network

Syntaxin 16, a Qa-SNARE (soluble N-ethylmaleimide-sensitive factor activating protein receptor), is involved in a number of membrane-trafficking activities, particularly transport processes at the trans-Golgi network (TGN). Recent works have now implicated syntaxin 16 in the autophagy process. In fact, syntaxin 16 appears to have dual roles, firstly in facilitating the transport of ATG9a-containing vesicles to growing autophagosomes, and secondly in autolysosome formation. The former involves a putative SNARE complex between syntaxin 16, VAMP7 and SNAP-47. The latter occurs via syntaxin 16’s recruitment by Atg8/LC3/GABARAP family proteins to autophagosomes and endo-lysosomes, where syntaxin 16 may act in a manner that bears functional redundancy with the canonical autophagosome Qa-SNARE syntaxin 17. Here, I discuss these recent findings and speculate on the mechanistic aspects of syntaxin 16’s newly found role in autophagy.

scholarly journals Regulation of intracellular membrane trafficking and cell dynamics by syntaxin-6

2012 ◽  
Vol 32 (4) ◽  
pp. 383-391 ◽  
Author(s):  
Jae-Joon Jung ◽  
Shivangi M. Inamdar ◽  
Ajit Tiwari ◽  
Amit Choudhury
Keyword(s):  
Membrane Trafficking ◽  
Critical Role ◽  
Cell Types ◽  
Intracellular Membrane ◽  
Cellular Functions ◽  
Cell Dynamics ◽  
Transport Pathways ◽  
Protein Receptor ◽  
Secretory Transport ◽  
Target Membrane

Intracellular membrane trafficking along endocytic and secretory transport pathways plays a critical role in diverse cellular functions including both developmental and pathological processes. Briefly, proteins and lipids destined for transport to distinct locations are collectively assembled into vesicles and delivered to their target site by vesicular fusion. SNARE (soluble N-ethylmaleimide-sensitive factor-attachment protein receptor) proteins are required for these events, during which v-SNAREs (vesicle SNAREs) interact with t-SNAREs (target SNAREs) to allow transfer of cargo from donor vesicle to target membrane. Recently, the t-SNARE family member, syntaxin-6, has been shown to play an important role in the transport of proteins that are key to diverse cellular dynamic processes. In this paper, we briefly discuss the specific role of SNAREs in various mammalian cell types and comprehensively review the various roles of the Golgi- and endosome-localized t-SNARE, syntaxin-6, in membrane trafficking during physiological as well as pathological conditions.

scholarly journals Regulation of Oxysterol-binding Protein Golgi Localization through Protein Kinase D–mediated Phosphorylation

2010 ◽  
Vol 21 (13) ◽  
pp. 2327-2337 ◽  
Author(s):  
Sokha Nhek ◽  
Mike Ngo ◽  
Xuemei Yang ◽  
Michelle M. Ng ◽  
Seth J. Field ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Protein Kinase ◽  
Binding Protein ◽  
Critical Role ◽  
Protein Kinase D ◽  
Cholesterol Depletion ◽  
Oxysterol Binding Protein ◽  
Golgi Localization ◽  
Golgi Network

Protein kinase D (PKD) plays a critical role at the trans-Golgi network by regulating the fission of transport carriers destined for the plasma membrane. Two known Golgi-localized PKD substrates, PI4-kinase IIIβ and the ceramide transfer protein CERT, mediate PKD signaling to influence vesicle trafficking to the plasma membrane and sphingomyelin synthesis, respectively. PKD is recruited and activated at the Golgi through interaction with diacylglycerol, a pool of which is generated as a by-product of sphingomyelin synthesis from ceramide. Here we identify a novel substrate of PKD at the Golgi, the oxysterol-binding protein OSBP. Using a substrate-directed phospho-specific antibody that recognizes the optimal PKD consensus motif, we show that PKD phosphorylates OSBP at Ser240 in vitro and in cells. We further show that OSBP phosphorylation occurs at the Golgi. Phosphorylation of OSBP by PKD does not modulate dimerization, sterol binding, or affinity for PI(4)P. Instead, phosphorylation attenuates OSBP Golgi localization in response to 25-hydroxycholesterol and cholesterol depletion, impairs CERT Golgi localization, and promotes Golgi fragmentation.

Distinct Initial SNARE Configurations Underlying the Diversity of Exocytosis

2012 ◽  
Vol 92 (4) ◽  
pp. 1915-1964 ◽  
Author(s):  
Haruo Kasai ◽  
Noriko Takahashi ◽  
Hiroshi Tokumaru
Keyword(s):  
Membrane Trafficking ◽  
Synaptic Vesicles ◽  
Cell Types ◽  
Snare Proteins ◽  
Attachment Protein ◽  
Protein Receptor ◽  
Large Dense Core Vesicles ◽  
Sensitive Factor ◽  
The Common ◽  
Kinetics Of

The dynamics of exocytosis are diverse and have been optimized for the functions of synapses and a wide variety of cell types. For example, the kinetics of exocytosis varies by more than five orders of magnitude between ultrafast exocytosis in synaptic vesicles and slow exocytosis in large dense-core vesicles. However, in all cases, exocytosis is mediated by the same fundamental mechanism, i.e., the assembly of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins. It is often assumed that vesicles need to be docked at the plasma membrane and SNARE proteins must be preassembled before exocytosis is triggered. However, this model cannot account for the dynamics of exocytosis recently reported in synapses and other cells. For example, vesicles undergo exocytosis without prestimulus docking during tonic exocytosis of synaptic vesicles in the active zone. In addition, epithelial and hematopoietic cells utilize cAMP and kinases to trigger slow exocytosis of nondocked vesicles. In this review, we summarize the manner in which the diversity of exocytosis reflects the initial configurations of SNARE assembly, including trans-SNARE, binary-SNARE, unitary-SNARE, and cis-SNARE configurations. The initial SNARE configurations depend on the particular SNARE subtype (syntaxin, SNAP25, or VAMP), priming proteins (Munc18, Munc13, CAPS, complexin, or snapin), triggering proteins (synaptotagmins, Doc2, and various protein kinases), and the submembraneous cytomatrix, and they are the key to determining the kinetics of subsequent exocytosis. These distinct initial configurations will help us clarify the common SNARE assembly processes underlying exocytosis and membrane trafficking in eukaryotic cells.

scholarly journals SNAP-23 regulates phagosome formation and maturation in macrophages

2012 ◽  
Vol 23 (24) ◽  
pp. 4849-4863 ◽  
Author(s):  
Chiye Sakurai ◽  
Hitoshi Hashimoto ◽  
Hideki Nakanishi ◽  
Seisuke Arai ◽  
Yoh Wada ◽  
...  
Keyword(s):  
Critical Role ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Protein Receptor ◽  
Sensitive Factor ◽  
Nadph Oxidase Complex ◽  
Uptake Activity ◽  
Fret Efficiency ◽  
Precise Role

Synaptosomal associated protein of 23 kDa (SNAP-23), a plasma membrane–localized soluble N-ethylmaleimide–sensitive factor attachment protein receptor (SNARE), has been implicated in phagocytosis by macrophages. For elucidation of its precise role in this process, a macrophage line overexpressing monomeric Venus–tagged SNAP-23 was established. These cells showed enhanced Fc receptor–mediated phagocytosis. Detailed analyses of each process of phagocytosis revealed a marked increase in the production of reactive oxygen species within phagosomes. Also, enhanced accumulation of a lysotropic dye, as well as augmented quenching of a pH-sensitive fluorophore were observed. Analyses of isolated phagosomes indicated the critical role of SNAP-23 in the functional recruitment of the NADPH oxidase complex and vacuolar-type H+-ATPase to phagosomes. The data from the overexpression experiments were confirmed by SNAP-23 knockdown, which demonstrated a significant delay in phagosome maturation and a reduction in uptake activity. Finally, for analyzing whether phagosomal SNAP-23 entails a structural change in the protein, an intramolecular Förster resonance energy transfer (FRET) probe was constructed, in which the distance within a TagGFP2-TagRFP was altered upon close approximation of the N-termini of its two SNARE motifs. FRET efficiency on phagosomes was markedly enhanced only when VAMP7, a lysosomal SNARE, was coexpressed. Taken together, our results strongly suggest the involvement of SNAP-23 in both phagosome formation and maturation in macrophages, presumably by mediating SNARE-based membrane traffic.

scholarly journals Syntaxin 7 and VAMP-7 are SolubleN-Ethylmaleimide–sensitive Factor Attachment Protein Receptors Required for Late Endosome–Lysosome and Homotypic Lysosome Fusion in Alveolar Macrophages

2000 ◽  
Vol 11 (7) ◽  
pp. 2327-2333 ◽  
Author(s):  
Diane McVey Ward ◽  
Jonathan Pevsner ◽  
Matthew A. Scullion ◽  
Michael Vaughn ◽  
Jerry Kaplan
Keyword(s):  
Alveolar Macrophages ◽  
Transmembrane Domain ◽  
Late Endosome ◽  
Endocytic Pathway ◽  
Attachment Protein ◽  
Protein Receptor ◽  
Early Endosomes ◽  
Sensitive Factor ◽  
Protein Receptors

Endocytosis in alveolar macrophages can be reversibly inhibited, permitting the isolation of endocytic vesicles at defined stages of maturation. Using an in vitro fusion assay, we determined that each isolated endosome population was capable of homotypic fusion. All vesicle populations were also capable of heterotypic fusion in a temporally specific manner; early endosomes, isolated 4 min after internalization, could fuse with endosomes isolated 8 min after internalization but not with 12-min endosomes or lysosomes. Lysosomes fuse with 12-min endosomes but not with earlier endosomes. Using homogenous populations of endosomes, we have identified Syntaxin 7 as a soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) required for late endosome–lysosome and homotypic lysosome fusion in vitro. A bacterially expressed human Syntaxin 7 lacking the transmembrane domain inhibited homotypic late endosome and lysosome fusion as well as heterotypic late endosome–lysosome fusion. Affinity-purified antibodies directed against Syntaxin 7 also inhibited lysosome fusion in vitro but had no affect on homotypic early endosome fusion. Previous work suggested that human VAMP-7 (vesicle-associated membrane protein-7) was a SNARE required for late endosome–lysosome fusion. A bacterially expressed human VAMP-7 lacking the transmembrane domain inhibited both late endosome–lysosome fusion and homotypic lysosome fusion in vitro. These studies indicate that: 1) fusion along the endocytic pathway is a highly regulated process, and 2) two SNARE molecules, Syntaxin 7 and human VAMP-7, are involved in fusion of vesicles in the late endocytic pathway in alveolar macrophages.

scholarly journals A new role for RINT-1 in SNARE complex assembly at the trans-Golgi network in coordination with the COG complex

2013 ◽  
Vol 24 (18) ◽  
pp. 2907-2917 ◽  
Author(s):  
Kohei Arasaki ◽  
Daichi Takagi ◽  
Akiko Furuno ◽  
Miwa Sohda ◽  
Yoshio Misumi ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Membrane Trafficking ◽  
Retrograde Transport ◽  
Snare Complex ◽  
Initial Contact ◽  
Complex Assembly ◽  
Trans Golgi Network ◽  
Cog Complex ◽  
Protein Receptor ◽  
Golgi Network

Docking and fusion of transport vesicles/carriers with the target membrane involve a tethering factor–mediated initial contact followed by soluble N-ethylmaleimide–sensitive factor attachment protein receptor (SNARE)–catalyzed membrane fusion. The multisubunit tethering CATCHR family complexes (Dsl1, COG, exocyst, and GARP complexes) share very low sequence homology among subunits despite likely evolving from a common ancestor and participate in fundamentally different membrane trafficking pathways. Yeast Tip20, as a subunit of the Dsl1 complex, has been implicated in retrograde transport from the Golgi apparatus to the endoplasmic reticulum. Our previous study showed that RINT-1, the mammalian counterpart of yeast Tip20, mediates the association of ZW10 (mammalian Dsl1) with endoplasmic reticulum–localized SNARE proteins. In the present study, we show that RINT-1 is also required for endosome-to–trans-Golgi network trafficking. RINT-1 uncomplexed with ZW10 interacts with the COG complex, another member of the CATCHR family complex, and regulates SNARE complex assembly at the trans-Golgi network. This additional role for RINT-1 may in part reflect adaptation to the demand for more diverse transport routes from endosomes to the trans-Golgi network in mammals compared with those in a unicellular organism, yeast. The present findings highlight a new role of RINT-1 in coordination with the COG complex.

scholarly journals Regulation of Membrane Trafficking by a Novel Cdc42-related Protein in Caenorhabditis elegans Epithelial Cells

2005 ◽  
Vol 16 (4) ◽  
pp. 1629-1639 ◽  
Author(s):  
S. Jenna ◽  
M.-E. Caruso ◽  
A. Emadali ◽  
D. T. Nguyên ◽  
M. Dominguez ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Epithelial Cells ◽  
Membrane Trafficking ◽  
Rho Gtpases ◽  
Related Protein ◽  
Recycling Endosomes ◽  
C Elegans ◽  
Apical Trafficking ◽  
Golgi Network

Rho GTPases are mainly known for their implication in cytoskeleton remodeling. They have also been recently shown to regulate various aspects of membrane trafficking. Here, we report the identification and the characterization of a novel Caenorhabditis elegans Cdc42-related protein, CRP-1, that shows atypical enzymatic characteristics in vitro. Expression in mouse fibroblasts revealed that, in contrast with CDC-42, CRP-1 was unable to reorganize the actin cytoskeleton and mainly localized to trans-Golgi network and recycling endosomes. This subcellular localization, as well as its expression profile restricted to a subset of epithelial-like cells in C. elegans, suggested a potential function for this protein in polarized membrane trafficking. Consistent with this hypothesis, alteration of CRP-1 expression affected the apical trafficking of CHE-14 in vulval and rectal epithelial cells and sphingolipids (C6-NBD-ceramide) uptake and/or trafficking in intestinal cells. However, it did not affect basolateral trafficking of myotactin in the pharynx and the targeting of IFB-2 and AJM-1, two cytosolic apical markers of intestine epithelial cells. Hence, our data demonstrate a function for CRP-1 in the regulation of membrane trafficking in a subset of cells with epithelial characteristics.

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