GILP family: a stress-responsive group of plant proteins containing a LITAF motif

Abstract

Lipopolysaccharide-induced tumor necrosis factor-α (LITAF) is a membrane protein that is highly dependent on correct location to exert transcription factor activity and protein quality control. In humans, LITAF, PIG7 (p53-inducible gene 7), and SIMPLE (small integral membrane protein of the lysosome/late endosome) refer to the same gene, which acts as a tumor suppressor. Several studies have shown that the transcription factor activity and nuclear translocation of LITAF protein are critical for the induction of several immune cells via classical pathways. In plants, LITAF protein corresponds to the plasma membrane protein AtGILP (Arabidopsis thaliana GSH-induced LITAF domain protein). The conservation of LITAF proteins across species and their putative role is still unclear. In this study, we investigate the LITAF-containing proteins, which we call GILP proteins, in Viridiplantae. We identified a total of 59 genes in 46 species, whose gene copies range from one to three. Phylogenetic analysis showed that multiple copies were originated via block duplication posteriorly to monocot and eudicot separation. Analysis of the LITAF domain of GILP proteins allowed the identification of a putative domain signature in Viridiplantae, containing a CXXCX41HXCPXC motif. The subcellular location for the majority of GILP proteins was predicted to be in the plasma membrane, based on a transmembrane domain positioned within the LITAF domain. In silico analysis showed that the GILP genes are neither tissue-specific nor ubiquitously expressed, being responsive to stress conditions. Finally, investigation of the GILP protein network resulted in the identification of genes whose families are known to be involved with biotic and/or abiotic stress responses. Together, the expression modulation of GILP genes associated with their plasma membrane location suggests that they could act in the signaling of biotic/abiotic stress response in plants.

Co‐expression networks of deacclimation‐impaired transcription factor mutants identified complex regulation of the cold stress release response

“…In the RRS, GILP had 44 additional unique co‐expressions in jub1 . Several previously identified co‐expressions of GILP with LSD1, AT4G34150, and NUDT7 (Cabreira‐Cagliari et al, 2018) were confirmed in the Col‐0 network “response to hypoxia.” Known co‐expressions of GILP with NUDT7 and AT4G34150 were not observed in jub1 but were present in mbf1c . Furthermore, GILP and NUDT7 were uniquely significantly co‐expressed with MBF1c in jub1 .…”

“…Stress‐responsive GILP (Cabreira‐Cagliari et al, 2018) seems to be particularly important in deacclimation. In the RRS, GILP had 44 additional unique co‐expressions in jub1 .…”

“…The upregulation and high co-expression of stress-responsive genes during deacclimation, might have contributed to enabling the mutants to retain their freezing tolerance longer than the wild type. The downregulation of stress-responsive genes in the analysis of three transcriptomic studies of Col-0 after 24 h of deacclimation(Vyse et al, 2019; Figure 9) supports this hypothesis.Stress-responsive GILP(Cabreira-Cagliari et al, 2018) seems to be particularly important in deacclimation. In the RRS, GILP had 44 additional unique co-expressions in jub1.…”