The LSD1-interacting protein GILP is a LITAF domain protein that negatively regulates hypersensitive cell death in Arabidopsis

• Published in: PloS one 2011-04, Vol.6 (4), p.e18750
• Main Authors: He, Shanping, Tan, Guihong, Liu, Qian, Huang, Kuowei, Ren, Jiao, Zhang, Xu, Yu, Xiangchun, Huang, Ping, An, Chengcai
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Amino acids; Analysis; Apoptosis; Apoptosis Regulatory Proteins - chemistry; Apoptosis Regulatory Proteins - genetics; Apoptosis Regulatory Proteins - metabolism; Arabidopsis; Arabidopsis - cytology; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis - microbiology; Arabidopsis Proteins - chemistry; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; Base Sequence; Biochemistry; Biology; Cell death; Cell Death - drug effects; Cell Membrane - drug effects; Cell Membrane - metabolism; Disease; DNA-Binding Proteins - metabolism; Fumonisin B1; Fumonisins - pharmacology; Gene expression; Gene Expression Regulation, Plant - drug effects; Genetic engineering; Genetically modified plants; Identification; Immunity; Innate immunity; Investigations; Laboratories; Life sciences; Ligands; Localization; Membrane proteins; Molecular Sequence Data; Mortality; Mutation; Pathogens; Plant resistance; Protein Binding - drug effects; Protein Interaction Mapping; Protein Structure, Tertiary; Protein Transport - drug effects; Proteins; Pseudomonas; Pseudomonas syringae - drug effects; Regulators; Regulatory mechanisms (biology); Tomatoes; Transcription Factors - metabolism; Transgenic plants; Tumor necrosis factor-TNF; Up-Regulation - drug effects; Yeast
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0018750

Hypersensitive cell death, a form of avirulent pathogen-induced programmed cell death (PCD), is one of the most efficient plant innate immunity. However, its regulatory mechanism is poorly understood. AtLSD1 is an important negative regulator of PCD and only two proteins, AtbZIP10 and AtMC1, have been reported to interact with AtLSD1. To identify a novel regulator of hypersensitive cell death, we investigate the possible role of plant LITAF domain protein GILP in hypersensitive cell death. Subcellular localization analysis showed that AtGILP is localized in the plasma membrane and its plasma membrane localization is dependent on its LITAF domain. Yeast two-hybrid and pull-down assays demonstrated that AtGILP interacts with AtLSD1. Pull-down assays showed that both the N-terminal and the C-terminal domains of AtGILP are sufficient for interactions with AtLSD1 and that the N-terminal domain of AtLSD1 is involved in the interaction with AtGILP. Real-time PCR analysis showed that AtGILP expression is up-regulated by the avirulent pathogen Pseudomonas syringae pv. tomato DC3000 avrRpt2 (Pst avrRpt2) and fumonisin B1 (FB1) that trigger PCD. Compared with wild-type plants, transgenic plants overexpressing AtGILP exhibited significantly less cell death when inoculated with Pst avrRpt2, indicating that AtGILP negatively regulates hypersensitive cell death. These results suggest that the LITAF domain protein AtGILP localizes in the plasma membrane, interacts with AtLSD1, and is involved in negatively regulating PCD. We propose that AtGILP functions as a membrane anchor, bringing other regulators of PCD, such as AtLSD1, to the plasma membrane. Human LITAF domain protein may be involved in the regulation of PCD, suggesting the evolutionarily conserved function of LITAF domain proteins in the regulation of PCD.