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Detecting N-myristoylation and S-acylation of Host and Pathogen Proteins in Plants Using Click Chemistry

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Detecting N-myristoylation and S-acylation of Host and Pathogen Proteins in Plants Using Click Chemistry

Patrick C Boyle et al. Plant Methods.

Abstract

Background: The plant plasma membrane is a key battleground in the war between plants and their pathogens. Plants detect the presence of pathogens at the plasma membrane using sensor proteins, many of which are targeted to this lipophilic locale by way of fatty acid modifications. Pathogens secrete effector proteins into the plant cell to suppress the plant's defense mechanisms. These effectors are able to access and interfere with the surveillance machinery at the plant plasma membrane by hijacking the host's fatty acylation apparatus. Despite the important involvement of protein fatty acylation in both plant immunity and pathogen virulence mechanisms, relatively little is known about the role of this modification during plant-pathogen interactions. This dearth in our understanding is due largely to the lack of methods to monitor protein fatty acid modifications in the plant cell.

Results: We describe a rapid method to detect two major forms of fatty acylation, N-myristoylation and S-acylation, of candidate proteins using alkyne fatty acid analogs coupled with click chemistry. We applied our approach to confirm and decisively demonstrate that the archetypal pattern recognition receptor FLS2, the well-characterized pathogen effector AvrPto, and one of the best-studied intracellular resistance proteins, Pto, all undergo plant-mediated fatty acylation. In addition to providing a means to readily determine fatty acylation, particularly myristoylation, of candidate proteins, this method is amenable to a variety of expression systems. We demonstrate this using both Arabidopsis protoplasts and stable transgenic Arabidopsis plants and we leverage Agrobacterium-mediated transient expression in Nicotiana benthamiana leaves as a means for high-throughput evaluation of candidate proteins.

Conclusions: Protein fatty acylation is a targeting tactic employed by both plants and their pathogens. The metabolic labeling approach leveraging alkyne fatty acid analogs and click chemistry described here has the potential to provide mechanistic details of the molecular tactics used at the host plasma membrane in the battle between plants and pathogens.

Keywords: Arabidopsis thaliana; Click chemistry; Fatty acylation; Myristoylation; Nicotiana benthamiana; Palmitoylation; Pathogen effectors; Pattern recognition receptors; Plasma membrane; Resistance proteins; S-acylation; Stearylation.

Figures

Fig. 1
Fig. 1
Experimental scheme for assessing fatty acylation of proteins in plant cells using clickable fatty acid analogs. Adapted from [46]
Fig. 2
Fig. 2
Fatty acid modifications of proteins involved in plant immunity. a Arabidopsis protoplasts were transformed with HA epitope-tagged FLS2 wild-type (WT) or an fls2 mutant encoding C830S, C831S. Protoplasts were treated with 10 μM Alk14, incubated for 6 h, and cells collected. Total protein was extracted, FLS2 proteins immunoprecipitated using anti-HA resin, and click chemistry performed. Incorporated Alk14 was visualized by fluorescence imaging and total protein was detected by anti-HA western blotting. b Transgenic Arabidopsis plants conditionally expressing avrPto were treated with 20 μM dexamethasone to induce transgene expression. Leaves were infiltrated twice with 10 μM Alk12, 6 h after induction and 6 h before sampling. Tissue was collected 30 h after induction and total protein extracted. AvrPto was immunoprecipitated using anti-AvrPto resin and a biotin tag added using click chemistry. Streptavidin-HRP western blotting was used to detect incorporation of Alk12. Anti-AvrPto western blotting was used to verify equal amounts of protein in all samples. c Nicotiana benthamiana leaves were infiltrated with Agrobacterium strains carrying avrPto-YFP fusion constructs encoding the WT protein or a G2A mutant. 10 μM Alk12 was infiltrated twice, 24 h after Agrobacterium infiltration and 6 h before sampling. Tissue was collected 48 h after transformation and total protein extracted. AvrPto proteins were immunoprecipitated using anti-GFP resin and a biotin tag attached using click chemistry. Incorporated Alk12 was detected by streptavidin-HRP western blotting. The anti-GFP western blot shows relative protein levels. d Nicotiana benthamiana was used to transiently express Pto-YFP fusions encoding the WT protein or a G2A mutant. 10 μM Alk12 was infiltrated twice, 24 h after Agrobacterium infiltration and 6 h before sampling. Tissue was collected 48 h after transformation, total protein extracted, and Pto proteins immunoprecipitated using anti-GFP resin. A biotin tag was attached using click chemistry and incorporation of Alk12 was detected by streptavidin-HRP western blotting. Protein levels were visualized by anti-GFP western blotting

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References

    1. Resh MD. Fatty acylation of proteins: new insights into membrane targeting of myristoylated and palmitoylated proteins. Biochim Biophys Acta. 1999;1451:1–16. doi: 10.1016/S0167-4889(99)00075-0. - DOI - PubMed
    1. Hemsley PA. The importance of lipid modified proteins in plants. New Phytol. 2015;205:476–489. doi: 10.1111/nph.13085. - DOI - PubMed
    1. Wright MH, Heal WP, Mann DJ, Tate EW. Protein myristoylation in health and disease. J Chem Biol. 2010;3:19–35. doi: 10.1007/s12154-009-0032-8. - DOI - PMC - PubMed
    1. Martin DDO, Beauchamp E, Berthiaume LG. Post-translational myristoylation: fat matters in cellular life and death. Biochimie. 2011;93:18–31. doi: 10.1016/j.biochi.2010.10.018. - DOI - PubMed
    1. Qi Q, Rajala RV, Anderson W, Jiang C, Rozwadowski K, Selvaraj G, et al. Molecular cloning, genomic organization, and biochemical characterization of myristoyl-CoA:protein N-myristoyltransferase from Arabidopsis thaliana. J Biol Chem. 2000;275:9673–9683. doi: 10.1074/jbc.275.13.9673. - DOI - PubMed

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