Format

Send to

Choose Destination
J Cell Sci. 2019 Jan 11. pii: jcs.222430. doi: 10.1242/jcs.222430. [Epub ahead of print]

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

Author information

1
Laboratory of Cell Biology, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands.
2
Present address: Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK.
3
Laboratory of Phytopathology, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands.
4
Present address: Department of Bionanoscience, Kavli Institute of NanoScience, TU Delft, Van der Maasweg 9, 2629 HZ Delft, The Netherlands.
5
Present address: Laboratory of Phytopathology, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands.
6
Department of Plant and Microbial Biology and Zurich-Basel Plant Science Center, University of Zurich, Zurich, Switzerland.
7
Laboratory of Cell Biology, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands tijs.ketelaar@wur.nl marcel.janson@wur.nl.

Abstract

During 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 nor Sec5 subunits localized to microtubule overlap regions in advance of cell plate construction 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.

KEYWORDS:

Cell plate; Exocyst; MAP65; Microtubule; Phragmoplast; Physcomitrella patens

PMID:
30635445
DOI:
10.1242/jcs.222430

Supplemental Content

Full text links

Icon for HighWire
Loading ...
Support Center