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Signal Peptide Peptidase and PI4Kβ1/2 play opposite roles in plant ER stress response and immunity.

Karen Thulasi DevendrakumarTony ShengZhe PengLeon PierdzigEdan JacksonVolker LipkaXin Li
Published in: Stress biology (2024)
The Arabidopsis pi4kβ1,2 mutant is mutated in the phosphatidylinositol 4-kinase (PI4K) β1 and PI4Kβ2 enzymes which are involved in the biosynthesis of phosphatidylinositol 4-phosphate (PI4P), a minor membrane lipid with important signaling roles. pi4kβ1,2 plants display autoimmunity and shorter roots. Though the pi4kβ1,2 mutant has been extensively characterized, the source of its autoimmunity remains largely unknown. In this study, through a genetic suppressor screen, we identified multiple partial loss-of-function alleles of signal peptide peptidase (spp) that can suppress all the defects of pi4kβ1,2. SPP is an intramembrane cleaving aspartic protease. Interestingly, pi4kβ1,2 plants display enhanced ER stress response and mutations in SPP can suppress such phenotype. Furthermore, reduced ER stress responses were observed in the spp single mutants. Overall, our study reveals a previously unknown function of PI4Kβ and SPP in ER stress and plant immunity.
Keyphrases
  • wild type
  • cell wall
  • protein kinase
  • transcription factor
  • breast cancer cells
  • multidrug resistant
  • high throughput
  • dna methylation
  • celiac disease
  • plant growth