Thu, 21 Aug 2008 11:09:48 BST CiteULike: sarus Caplan http://www.citeulike.org/user/saru/author/Caplan CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/saru/article/2387788 <i>Cell, Vol. 132, No. 3. (8 February 2008), pp. 449-462.</i><br /><br />Summary Plant innate immunity relies on the recognition of pathogen effector molecules by nucleotide-binding-leucine-rich repeat (NB-LRR) immune receptor families. Previously we have shown the N immune receptor, a member of TIR-NB-LRR family, indirectly recognizes the 50 kDa helicase (p50) domain of Tobacco mosaic virus (TMV) through its TIR domain. We have identified an N receptor-interacting protein, NRIP1, that directly interacts with both N's TIR domain and p50. NRIP1 is a functional rhodanese sulfurtransferase and is required for N to provide complete resistance to TMV. Interestingly, NRIP1 that normally localizes to the chloroplasts is recruited to the cytoplasm and nucleus by the p50 effector. As a consequence, NRIP1 interacts with N only in the presence of the p50 effector. Our findings show that a chloroplastic protein is intimately involved in pathogen recognition. We propose that N's activation requires a prerecognition complex containing the p50 effector and NRIP1. Chloroplastic Protein NRIP1 Mediates Innate Immune Receptor Recognition of a Viral Effector Jeffrey Caplan Padmavathi Mamillapalli Tessa Burch-Smith Kirk Czymmek SP Dinesh-Kumar doi:10.1016/j.cell.2007.12.031 Cell, Vol. 132, No. 3. (8 February 2008), pp. 449-462. 2008-02-16T02:25:25-00:00 2008 Cell 132 3 449 462 n nrip r http://www.citeulike.org/user/saru/article/1109192 <i>PLoS Biol, Vol. 5, No. 3. (13 February 2007)</i><br /><br />Plant innate immunity is mediated by Resistance (R) proteins, which bear a striking resemblance to animal molecules of similar function. Tobacco N is a TIR-NB-LRR R gene that confers resistance to Tobacco mosaic virus, specifically the p50 helicase domain. An intriguing question is how plant R proteins recognize the presence of pathogen-derived Avirulence (Avr) elicitor proteins. We have used biochemical cell fraction and immunoprecipitation in addition to confocal fluorescence microscopy of living tissue to examine the association between N and p50. Surprisingly, both N and p50 are cytoplasmic and nuclear proteins, and N's nuclear localization is required for its function. We also demonstrate an in planta association between N and p50. Further, we show that N's TIR domain is critical for this association, and indeed, it alone can associate with p50. Our results differ from current models for plant innate immunity that propose detection is mediated solely through the LRR domains of these molecules. The data we present support an intricate process of pathogen elicitor recognition by R proteins involving multiple subcellular compartments and the formation of multiple protein complexes. A Novel Role for the TIR Domain in Association with Pathogen-Derived Elicitors. Tessa M Burch-Smith Michael Schiff Jeffrey L Caplan Jeffrey Tsao Kirk Czymmek Savithramma P Dinesh-Kumar doi:10.1371/journal.pbio.0050068 PLoS Biol, Vol. 5, No. 3. (13 February 2007) 2007-02-16T01:17:05-00:00 2007 PLoS Biol 1545-7885 5 3 n r