title: Plant VAP27 proteins: domain characterization, intracellular localization and role in plant development.
abstract: The endoplasmic reticulum (ER) is connected to the plasma membrane (PM) through the plant-specific NETWORKED protein, NET3C, and phylogenetically conserved vesicle-associated membrane protein-associated proteins (VAPs). Ten VAP homologues (VAP27-1 to 27-10) can be identified in the Arabidopsis genome and can be divided into three clades. Representative members from each clade were tagged with fluorescent protein and expressed in Nicotiana benthamiana. Proteins from clades I and III localized to the ER as well as to ER/PM contact sites (EPCSs), whereas proteins from clade II were found only at the PM. Some of the VAP27-labelled EPCSs localized to plasmodesmata, and we show that the mobility of VAP27 at EPCSs is influenced by the cell wall. EPCSs closely associate with the cytoskeleton, but their structure is unaffected when the cytoskeleton is removed. VAP27-labelled EPCSs are found in most cell types in Arabidopsis, with the exception of cells in early trichome development. Arabidopsis plants expressing VAP27-GFP fusions exhibit pleiotropic phenotypes, including defects in root hair morphogenesis. A similar effect is also observed in plants expressing VAP27 RNAi. Taken together, these data indicate that VAP27 proteins used at EPCSs are essential for normal ER-cytoskeleton interaction and for plant development.
authors.affiliation: School of Biological and Biomedical Sciences, Durham University, South Road, Durham, DH1 3LE, UK.
authors.forename: Pengwei
authors.initials: P
authors.lastname: Wang
authors.affiliation: School of Biological and Biomedical Sciences, Durham University, South Road, Durham, DH1 3LE, UK.
authors.forename: Christine
authors.initials: C
authors.lastname: Richardson
authors.affiliation: School of Biological and Biomedical Sciences, Durham University, South Road, Durham, DH1 3LE, UK.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Hawkins
authors.affiliation: College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK.
authors.forename: Imogen
authors.initials: I
authors.lastname: Sparkes
authors.affiliation: Department of Biological and Biomedical Sciences, Oxford Brookes University, Gipsy Lane, Oxford, OX3 0BP, UK.
authors.forename: Chris
authors.initials: C
authors.lastname: Hawes
authors.affiliation: School of Biological and Biomedical Sciences, Durham University, South Road, Durham, DH1 3LE, UK.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Hussey
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D017930:Genes, Reporter; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism; D010802:Phylogeny; D030821:Plants, Genetically Modified; D031425:Plasmodesmata / Q000378:metabolism; D000072417:Protein Domains; D050683:R-SNARE Proteins / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D014026:Nicotiana / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure
chemical_list: D029681:Arabidopsis Proteins; C000601165:At3g60600 protein, Arabidopsis; D008565:Membrane Proteins; D050683:R-SNARE Proteins
keywords: NET superfamily; Scs2; VAP27; endoplasmic reticulum (ER); endoplasmic reticulum/plasma membrane (ER/PM) contact sites (EPCSs)