Interaction and Regulation Between Lipid Mediator Phosphatidic Acid and Circadian Clock Regulators

Abstract

Circadian clocks play important roles in regulating cellular metabolism, but the reciprocal effect that metabolism has on the clock is largely unknown in plants. Here, we show that the central glycerolipid metabolite and lipid mediator phosphatidic acid (PA) interacts with and modulates the function of the core clock regulators LATE ELONGATED HYPOCOTYL (LHY) and CIRCADIAN CLOCK ASSOCIATED1 (CCA1) in Arabidopsis (Arabidopsis thaliana). PA reduced the ability of LHY and CCA1 to bind the promoter of their target gene TIMING OF CAB EXPRESSION1. Increased PA accumulation and inhibition of PAproducing enzymes had opposite effects on circadian clock outputs. Diurnal change in levels of several membrane phospholipid species, including PA, observed in wild type was lost in the LHY and CCA1 double knockout mutant. Storage lipid accumulation was also affected in the clock mutants. These results indicate that the interaction of PA with the clock regulator may function as a cellular conduit to integrate the circadian clock with lipid metabolism.

Phosphatidic acid directly binds with rice potassium channel OsAKT2 to inhibit its activity

“…For example, sphingosine kinases (SPHK1 and SPHK2) and MAPK kinases (MKK7 and MKK9) bind to 16:0–18:1 PA and 18:1–18:1 PA equally well, but not to 18:2–18:2 PA (Guo et al , 2011; Shen et al , 2019). An MYB transcription factor (WER) and two glyceraldehyde‐3‐phosphate dehydrogenases (GAPC1 and GAPC2) show no specific preference for PA species (Kim et al , 2013; Yao et al , 2013), whereas the transcription factors LHY and CCA1 only bind to 16:0‐containing PA (Kim et al , 2019). These different PA species preferences suggest that PA acyl chain composition is a crucial determinant for PA interaction with specific target proteins.…”

Different Light Radiation Intensities on Cotton: A Physiological Approach

“…This can cause changes in the photolysis of the water, which consequently results in the release of electrons during photosynthesis due to the increase or restriction of the photons that are affecting the plant [13]. In this study, the ideal intensity observed was approximately 1500 μmol m It is worth noting that, even at different periods of the day, a variation occurs in the intensity of light energy, which influences the CO 2 assimilation rate of the leaves [18] demonstrating this phenomenon that occurs naturally during the day.…”

Nonspecific phospholipase C6 increases seed oil production in oilseed Brassicaceae plants

“…Plant seed oil content and yield are complex traits influenced by multiple genes (Graham, 2008; Xing & Zhang, 2010; Li‐Beisson et al , 2013; Cai et al , 2016). Specific genes involved in lipid biosynthesis (Zhang et al , 2009; Aznar‐Moreno & Durrett, 2017), hydrolysis (Eastmond, 2006; Kelly et al , 2011) and transport (S. Kim et al , 2013; N. Li et al , 2015), as well as in glycolysis and transcriptional regulation (Cernac & Benning, 2004; Mu et al , 2008; Santos‐Mendoza et al , 2008; Kim et al , 2019), have been shown to influence seed oil accumulation. In addition, proteins involved in lipid droplet formation also affect lipid accumulation (Cai et al , 2015; Pyc et al , 2017).…”

“…Total proteins were extracted from 3‐wk‐old Arabidopsis, Camelina and tobacco leaves using a protein extraction buffer (50 mM Tris‐HCl, pH 7.5, 150 mM NaCl, 0.5% Triton X‐100 (v/v), 1 mM DTT and 1 mM PMSF). After centrifugation at 3000 g for 10 min at 4°C, an aliquot from the supernatant was used as a total protein (Kim et al , 2019). The subcellular fractionations from total protein extraction were separated as follows: the supernatant was centrifuged at 100 000 g for 60 min at 4°C and the resultant supernatant (referred to as the soluble cytosol fraction) was pellet‐washed with protein extraction buffer three times, and centrifuged at 100 000 g for 60 min; the remaining pellet is referred to as the microsomal fraction.…”

“…Protein concentrations were measured using the Bradford assay (Bio‐Rad, 500‐0205). Ten micrograms of proteins were dissolved in SDS‐PAGE loading buffer, boiled for 10 min for Western blot as described previously (Kim et al , 2019).…”