scholarly journals Exocyst subunit Sec6 is positioned by microtubule overlaps in the moss phragmoplast prior to the arrival of cell plate membrane

2018 ◽  
Author(s):  
Han Tang ◽  
Jeroen de Keijzer ◽  
Elysa Overdijk ◽  
Els Sweep ◽  
Maikel Steentjes ◽  
...  
Keyword(s):  
Physcomitrella Patens ◽  
Membrane Vesicle ◽  
Cell Plate ◽  
Vesicle Fusion ◽  
Physical Interaction ◽  
Recruitment Pattern ◽  
Time Resolved ◽  
Plant Cytokinesis ◽  
Important Regulator ◽  
Summary Statement

AbstractDuring plant cytokinesis a radially expanding membrane-enclosed cell plate is formed from fusing vesicles that compartmentalizes the cell in two. How fusion is spatially restricted to the site of cell plate formation is unknown. Aggregation of cell-plate membrane starts near regions of microtubule overlap within the bipolar phragmoplast apparatus of the moss Physcomitrella patens. Since vesicle fusion generally requires coordination of vesicle tethering and subsequent fusion activity we analysed the subcellular localization of several subunits of the exocyst, a tethering complex active during plant cytokinesis. We found that Sec6, but neither Sec3 or Sec5 subunits localized to microtubule overlap regions in advance of cell plate construction started in moss. Moreover, Sec6 exhibited a conserved physical interaction with an orthologue of the Sec1/Munc18 protein KEULE, an important regulator for cell-plate membrane vesicle fusion in Arabidopsis. Recruitment of PpKEULE and vesicles to the early cell plate was delayed upon Sec6 gene silencing. Our findings thus suggest that vesicle-vesicle fusion is in part enabled by a pool of exocyst subunits at microtubule overlaps that is recruited independent of the delivery of vesicles.Summary statementWe performed a time-resolved localization screen of multiple subunits of the exocyst complex throughout moss cytokinesis and show that each subunit has a unique spatiotemporal recruitment pattern.

scholarly journals The Arabidopsis KNOLLE Protein Is a Cytokinesis-specific Syntaxin

1997 ◽  
Vol 139 (6) ◽  
pp. 1485-1493 ◽  
Author(s):  
Martina H. Lauber ◽  
Irene Waizenegger ◽  
Thomas Steinmann ◽  
Heinz Schwarz ◽  
Ulrike Mayer ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Rabbit Antiserum ◽  
Microscopic Analysis ◽  
Cell Plate ◽  
Vesicle Fusion ◽  
Higher Plant ◽  
Electron Microscopic ◽  
Vesicle Traffic ◽  
Plant Cytokinesis ◽  
Dividing Cells

In higher plant cytokinesis, plasma membrane and cell wall originate by vesicle fusion in the plane of cell division. The Arabidopsis KNOLLE gene, which is required for cytokinesis, encodes a protein related to vesicle-docking syntaxins. We have raised specific rabbit antiserum against purified recombinant KNOLLE protein to show biochemically and by immunoelectron microscopy that KNOLLE protein is membrane associated. Using immunofluorescence microscopy, KNOLLE protein was found to be specifically expressed during mitosis and, unlike the plasma membrane H+-ATPase, to localize to the plane of division during cytokinesis. Arabidopsis dynamin-like protein ADL1 accumulates at the plane of cell plate formation in knolle mutant cells as in wild-type cells, suggesting that cytokinetic vesicle traffic is not affected. Furthermore, electron microscopic analysis indicates that vesicle fusion is impaired. KNOLLE protein was detected in mitotically dividing cells of various parts of the developing plant, including seedling root, inflorescence meristem, floral meristems and ovules, and the cellularizing endosperm, but not during cytokinesis after the male second meiotic division. Thus, KNOLLE is the first syntaxin-like protein that appears to be involved specifically in cytokinetic vesicle fusion.

scholarly journals Functional characterization of the KNOLLE-interacting t-SNARE AtSNAP33 and its role in plant cytokinesis

2001 ◽  
Vol 155 (2) ◽  
pp. 239-250 ◽  
Author(s):  
Maren Heese ◽  
Xavier Gansel ◽  
Liliane Sticher ◽  
Peter Wick ◽  
Markus Grebe ◽  
...  
Keyword(s):  
Cell Division ◽  
Membrane Fusion ◽  
Functional Characterization ◽  
Cell Plate ◽  
Yeast Two Hybrid ◽  
Division Plane ◽  
Plant Cytokinesis ◽  
Cell Plate Formation ◽  
Plate Formation ◽  
Two Hybrid

Cytokinesis requires membrane fusion during cleavage-furrow ingression in animals and cell plate formation in plants. In Arabidopsis, the Sec1 homologue KEULE (KEU) and the cytokinesis-specific syntaxin KNOLLE (KN) cooperate to promote vesicle fusion in the cell division plane. Here, we characterize AtSNAP33, an Arabidopsis homologue of the t-SNARE SNAP25, that was identified as a KN interactor in a yeast two-hybrid screen. AtSNAP33 is a ubiquitously expressed membrane-associated protein that accumulated at the plasma membrane and during cell division colocalized with KN at the forming cell plate. A T-DNA insertion in the AtSNAP33 gene caused loss of AtSNAP33 function, resulting in a lethal dwarf phenotype. atsnap33 plantlets gradually developed large necrotic lesions on cotyledons and rosette leaves, resembling pathogen-induced cellular responses, and eventually died before flowering. In addition, mutant seedlings displayed cytokinetic defects, and atsnap33 in combination with the cytokinesis mutant keu was embryo lethal. Analysis of the Arabidopsis genome revealed two further SNAP25-like proteins that also interacted with KN in the yeast two-hybrid assay. Our results suggest that AtSNAP33, the first SNAP25 homologue characterized in plants, is involved in diverse membrane fusion processes, including cell plate formation, and that AtSNAP33 function in cytokinesis may be replaced partially by other SNAP25 homologues.

Time-Resolved Neutron Reflectivity during Supported Membrane Formation by Vesicle Fusion

Langmuir ◽  
2017 ◽  
Vol 33 (40) ◽  
pp. 10598-10605 ◽  
Author(s):  
Alexandros Koutsioubas ◽  
Marie-Sousai Appavou ◽  
Didier Lairez
Keyword(s):  
Vesicle Fusion ◽  
Neutron Reflectivity ◽  
Membrane Formation ◽  
Time Resolved ◽  
Supported Membrane

scholarly journals Endocytosis of Cell Surface Material Mediates Cell Plate Formation during Plant Cytokinesis

2006 ◽  
Vol 10 (1) ◽  
pp. 137-150 ◽  
Author(s):  
Pankaj Dhonukshe ◽  
František Baluška ◽  
Markus Schlicht ◽  
Andrej Hlavacka ◽  
Jozef Šamaj ◽  
...  
Keyword(s):  
Cell Surface ◽  
Cell Plate ◽  
Surface Material ◽  
Plant Cytokinesis ◽  
Cell Plate Formation ◽  
Plate Formation

scholarly journals Phosphatidylinositol 4,5-bisphosphate drives Ca2+-independent membrane penetration by the tandem C2 domain proteins synaptotagmin-1 and Doc2β

2019 ◽  
Vol 294 (28) ◽  
pp. 10942-10953 ◽  
Author(s):  
Mazdak M. Bradberry ◽  
Huan Bao ◽  
Xiaochu Lou ◽  
Edwin R. Chapman
Keyword(s):  
Vesicle Fusion ◽  
Membrane Lipid ◽  
Neuroendocrine Cells ◽  
Dependent Manner ◽  
C2 Domain ◽  
Binding Modes ◽  
Membrane Penetration ◽  
Time Resolved ◽  
High Affinity ◽  
Fluorescence Measurements

Exocytosis mediates the release of neurotransmitters and hormones from neurons and neuroendocrine cells. Tandem C2 domain proteins in the synaptotagmin (syt) and double C2 domain (Doc2) families regulate exocytotic membrane fusion via direct interactions with Ca2+ and phospholipid bilayers. Syt1 is a fast-acting, low-affinity Ca2+ sensor that penetrates membranes upon binding Ca2+ to trigger synchronous vesicle fusion. The closely related Doc2β is a slow-acting, high-affinity Ca2+ sensor that triggers spontaneous and asynchronous vesicle fusion, but whether it also penetrates membranes is unknown. Both syt1 and Doc2β bind the dynamically regulated plasma membrane lipid phosphatidylinositol 4,5-bisphosphate (PIP2), but it is unclear whether PIP2 serves only as a membrane contact or enables specialized membrane-binding modes by these Ca2+ sensors. Furthermore, it has been shown that PIP2 uncaging can trigger rapid, syt1-dependent exocytosis in the absence of Ca2+ influx, suggesting that current models for the action of these Ca2+ sensors are incomplete. Here, using a series of steady-state and time-resolved fluorescence measurements, we show that Doc2β, like syt1, penetrates membranes in a Ca2+-dependent manner. Unexpectedly, we observed that PIP2 can drive membrane penetration by both syt1 and Doc2β in the absence of Ca2+, providing a plausible mechanism for Ca2+-independent, PIP2-dependent exocytosis. Quantitative measurements of penetration depth revealed that, in the presence of Ca2+, PIP2 drives Doc2β, but not syt1, substantially deeper into the membrane, defining a biophysical regulatory mechanism specific to this high-affinity Ca2+ sensor. Our results provide evidence of a novel role for PIP2 in regulating, and under some circumstances triggering, exocytosis.

scholarly journals Expansion of the Cell Plate in Plant Cytokinesis Requires a Kinesin-like Protein/MAPKKK Complex

Cell ◽  
2002 ◽  
Vol 109 (1) ◽  
pp. 87-99 ◽  
Author(s):  
Ryuichi Nishihama ◽  
Takashi Soyano ◽  
Masaki Ishikawa ◽  
Satoshi Araki ◽  
Hirokazu Tanaka ◽  
...  
Keyword(s):  
Cell Plate ◽  
Plant Cytokinesis

scholarly journals The cell polarity proteins Boi1p and Boi2p stimulate vesicle fusion at the plasma membrane of yeast cells

2017 ◽  
Author(s):  
Jochen Kustermann ◽  
Yehui Wu ◽  
Lucia Rieger ◽  
Dirk Dedden ◽  
Tamara Phan ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Vesicle Fusion ◽  
Snare Complex ◽  
Yeast Cells ◽  
Protein Interaction Data ◽  
Polar Growth ◽  
Interaction Data ◽  
Summary Statement ◽  
Snare Complex Formation ◽  
Novel Protein

AbstractEukaryotic cells can direct secretion to defined regions of their plasma membrane. These regions are distinguished by an elaborate architecture of proteins and lipids that are specialized to capture and fuse post-Golgi vesicles. Here we show that the proteins Boi1p and Boi2p are important elements of this area of active exocytosis at the tip of growing yeast cells. Cells lacking Boi1p and Boi2p accumulate secretory vesicles in their bud. The essential PH domains of Boi1p and Boi2p interact with Sec1p, a protein required for SNARE complex formation and vesicle fusion. Sec1p loses its tip localization in cells depleted of Boi1p and Boi2p but can partially compensate for their loss upon overexpression. The capacity to simultaneously bind phospholipids, Sec1p, multiple subunits of the exocyst, Cdc42p, and the module for generating active Cdc42p identify Boi1p and Boi2p as essential mediators between exocytosis and polar growth.Summary statementA novel protein complex connects vesicle fusion with Cdc42p activation. Genetic and protein interaction data suggest that its central members Boi1p and Boi2p chaperone the formation of the docking complex.

scholarly journals Control of plant cytokinesis by an NPK1–mediated mitogen–activated protein kinase cascade

2002 ◽  
Vol 357 (1422) ◽  
pp. 767-775 ◽  
Author(s):  
Takashi Soyano ◽  
Masaki Ishikawa ◽  
Ryuichi Nishihama ◽  
Satoshi Araki ◽  
Mayumi Ito ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Plant Cells ◽  
Cell Plate ◽  
Mitogen Activated Protein Kinase ◽  
Cross Wall ◽  
Daughter Cells ◽  
Plant Cytokinesis ◽  
Mitogen Activated Protein ◽  
Kinase Cascade ◽  
Protein Kinase Cascade

Cytokinesis is the last essential step in the distribution of genetic information to daughter cells and partition of the cytoplasm. In plant cells, various proteins have been found in the phragmoplast, which corresponds to the cytokinetic apparatus, and in the cell plate, which corresponds to a new cross wall, but our understanding of the functions of these proteins in cytokinesis remains incomplete. Reverse genetic analysis of NPK1 MAPKKK (nucleus– and phragmoplast–localized protein kinase 1 mitogen–activated protein kinase kinase kinase) and investigations of factors that might be functionally related to NPK1 have helped to clarify new aspects of the mechanisms of cytokinesis in plant cells. In this review, we summarize the evidence for the involvement of NPK1 in cytokinesis. We also describe the characteristics of a kinesin–like protein and the homologue of a mitogen–activated protein kinase that we identified recently, and we discuss possible relationships among these proteins in cytokinesis.

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