Phosphoinositides in plant-pathogen interaction: trends and perspectives

Zarreen, Fauzia; Kumar, Kamal; Chakraborty, Supriya

doi:10.1007/s44154-023-00082-5

Cited by 5 publications

(1 citation statement)

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“…PI4Kβs catalyze the phosphorylation of the membrane lipid phosphatidylinositol (PI) to form phosphatidylinositol-4-phosphate (PI4P), a lipid component of the plasma membrane and other organellar membranes. They were known to have roles in regulating plant development and a host of cellular functions including plant immune responses ( Marković & Jaillais, 2022 ; Zarreen et al, 2023 ). The enhanced disease resistance and constitutive high levels of the defense hormone salicylic acid (SA) in pi4kβ1,2 have been previously described ( Šašek et al, 2014 ; Antignani et al, 2015 ).…”

Section: Resultsmentioning

confidence: 99%

Arabidopsis Tubby domain‐containing F‐box proteins positively regulate immunity by modulating PI4Kβ protein levels

et al. 2023

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Summary The Tubby domain, named after the TUBBY protein in mice, binds to phosphatidylinositol 4,5‐bisphosphate. Arabidopsis has 11 Tubby domain‐containing proteins referred to as Tubby‐Like Proteins (TLPs). Of the 11 TLPs, 10 possess the N‐terminal F‐box domain, which can interact with SKP‐like proteins and form SKP1‐Cullin‐F‐box E3 ligase complexes. Although mice TUBBY has been extensively studied, plant TLPs' functions are scarcely detailed. In this study, we show that the Arabidopsis Tubby‐like protein 6 (TLP6) and its redundant homologs, TLP1, TLP2, TLP5, and TLP10, positively regulate Arabidopsis immune responses. Furthermore, in an immunoprecipitation mass spectrometry analysis to search for ubiquitination substrates of the TLPs, we identified two redundant phosphoinositide biosynthesis enzymes, phosphatidylinositol 4‐kinase β proteins (PI4Kβs), PI4Kβ1 and PI4Kβ2, as TLP interactors. Importantly, TLP6 overexpression lines fully phenocopy the phenotypes of the pi4kβ1,2 mutant, while TLP6 overexpression also leads to increased PI4Kβ2 ubiquitination and reduction in its protein level in a proteasome‐dependent manner. Most significantly, TLP6 overexpression does not further enhance the autoimmunity of the pi4kβ1,2 double mutant, supporting the hypothesis that TLP6 targets the PI4Kβs for ubiquitination and degradation. Thus, our study reveals a novel mechanism where TLPs promote plant immune responses by modulating the PI4Kβs protein levels.

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