Specific targeting of a plasmodesmal protein affecting cell-to-cell communication

• Published in: PLoS biology Vol. 6; no. 1; p. e7
• Main Authors: Thomas, Carole L, Bayer, Emmanuelle M, Ritzenthaler, Christophe, Fernandez-Calvino, Lourdes, Maule, Andrew J
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 01-01-2008; Public Library of Science (PLoS)
• Subjects: Amino Acid Sequence; Arabidopsis - genetics; Arabidopsis - growth & development; Arabidopsis - metabolism; Arabidopsis Proteins - chemistry; Arabidopsis Proteins - classification; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Biology; Carrier Proteins - chemistry; Carrier Proteins - classification; Carrier Proteins - genetics; Carrier Proteins - metabolism; Cell Communication; Cells; Cellular Biology; Communication; Extracellular Matrix - metabolism; Kinases; Life Sciences; Molecular Sequence Data; Mutation - genetics; Phylogenetics; Phylogeny; Plant Biology; Plasmids; Plasmodesmata - metabolism; Protein Transport; Proteins; Sequence Alignment; Signal Transduction; Tobacco; Amino Acid Sequence; Extracellular Matrix; Signal Transduction; Arabidopsis; Cell Communication; Molecular Sequence Data; Phylogeny; Protein Transport; Sequence Alignment; Arabidopsis Proteins; Mutation; Plasmodesmata; Carrier Proteins
• ISSN: 1545-7885; 1544-9173; 1545-7885
• DOI: 10.1371/journal.pbio.0060007

Plasmodesmata provide the cytoplasmic conduits for cell-to-cell communication throughout plant tissues and participate in a diverse set of non-cell-autonomous functions. Despite their central role in growth and development and defence, resolving their modus operandi remains a major challenge in plant biology. Features of protein sequences and/or structure that determine protein targeting to plasmodesmata were previously unknown. We identify here a novel family of plasmodesmata-located proteins (called PDLP1) whose members have the features of type I membrane receptor-like proteins. We focus our studies on the first identified type member (namely At5g43980, or PDLP1a) and show that, following its altered expression, it is effective in modulating cell-to-cell trafficking. PDLP1a is targeted to plasmodesmata via the secretory pathway in a Brefeldin A-sensitive and COPII-dependent manner, and resides at plasmodesmata with its C-terminus in the cytoplasmic domain and its N-terminus in the apoplast. Using a deletion analysis, we show that the single transmembrane domain (TMD) of PDLP1a contains all the information necessary for intracellular targeting of this type I membrane protein to plasmodesmata, such that the TMD can be used to target heterologous proteins to this location. These studies identify a new family of plasmodesmal proteins that affect cell-to-cell communication. They exhibit a mode of intracellular trafficking and targeting novel for plant biology and provide technological opportunities for targeting different proteins to plasmodesmata to aid in plasmodesmal characterisation.