PMID:16126836

Citation	Lee, JY, Taoka, K, Yoo, BC, Ben-Nissan, G, Kim, DJ and Lucas, WJ (2005) Plasmodesmal-associated protein kinase in tobacco and Arabidopsis recognizes a subset of non-cell-autonomous proteins. Plant Cell 17:2817-31
Abstract	Cell-to-cell communication in plants involves the trafficking of macromolecules through specialized intercellular organelles, termed plasmodesmata. This exchange of proteins and RNA is likely regulated, and a role for protein phosphorylation has been implicated, but specific components remain to be identified. Here, we describe the molecular characterization of a plasmodesmal-associated protein kinase (PAPK). A 34-kD protein, isolated from a plasmodesmal preparation, exhibits calcium-independent kinase activity and displays substrate specificity in that it recognizes a subset of viral and endogenous non-cell-autonomous proteins. This PAPK specifically phosphorylates the C-terminal residues of tobacco mosaic virus movement protein (TMV MP); this posttranslational modification has been shown to affect MP function. Molecular analysis of purified protein established that tobacco (Nicotiana tabacum) PAPK is a member of the casein kinase I family. Subcellular localization studies identified a possible Arabidopsis thaliana PAPK homolog, PAPK1. TMV MP and PAPK1 are colocalized within cross-walls in a pattern consistent with targeting to plasmodesmata. Moreover, Arabidopsis PAPK1 also phosphorylates TMV MP in vitro at its C terminus. These results strongly suggest that Arabidopsis PAPK1 is a close homolog of tobacco PAPK. Thus, PAPK1 represents a novel plant protein kinase that is targeted to plasmodesmata and may play a regulatory role in macromolecular trafficking between plant cells.
Links	PubMed PMC1242275 Online version:10.1105/tpc.105.034330
Keywords	Arabidopsis/enzymology; Arabidopsis/genetics; Arabidopsis Proteins/genetics; Arabidopsis Proteins/isolation & purification; Arabidopsis Proteins/metabolism; Carrier Proteins/metabolism; Casein Kinase I/chemistry; Cell Communication/genetics; Conserved Sequence; Molecular Sequence Data; Phosphorylation; Phylogeny; Plasmodesmata/enzymology; Plasmodesmata/genetics; Protein Kinases/genetics; Protein Kinases/isolation & purification; Protein Kinases/metabolism; Protein Processing, Post-Translational/genetics; Protein Transport/genetics; Sequence Homology, Amino Acid; Tobacco/enzymology; Tobacco/genetics
edit table

Annotations

Gene product	Qualifier	GO ID	GO term name	Evidence Code	with/from	Aspect	Notes	Status
edit table

References

See Help:References for how to manage references in GONUTS.