c-Src inhibitor PP2 inhibits head and neck cancer progression through regulation of the epithelial-mesenchymal transition.

Head and neck squamous cell carcinoma (HNSCC) is one of the most common cancer, causing considerable mortality and morbidity worldwide. Although HNSCC management has been extensively studied, the treatment outcomes have not improved - the 5-year survival rate of patients with HNSCC is 40%. Recent studies on the development of a novel HNSCC treatment have highlighted proto-oncogene tyrosine-protein kinase Src (c-Src) as one of the major therapeutic targets. However, the clinical efficacy of c-Src inhibitors against HNSCC was not comparable to that obtained in vitro. Furthermore, the molecular mechanisms underlying the efficacy of c-Src inhibitors remain elusive. In this study, we assessed the efficacy of 4-amino-5-(4-chlorophenyl)-7-(dimethylethyl)pyrazolo[3,4-d] pyrimidine (PP2), a selective c-Src inhibitor on HSNCC. Nine HNSCC cell lines (SNU1041, Fraud, SNU46, SNU1076, SNU899, SCC1483, YD15, YD9, and YD10-) were screened, and the effects of PP2 were evaluated using wound healing, apoptosis, and invasion assays. Western blot analysis of downstream markers was conducted to assess the specific mechanism of action of PP2 in HNSCC. The therapeutic efficacy of PP2 was further evaluated in xenograft mice. PP2 reduced tumor cell growth both in vitro and in vivo. Furthermore, it enhanced tumor cell apoptosis in cell lines and prevented metastasis in mice. PP2 also regulated the epithelial-mesenchymal transition pathway downstream of c-Src. More specifically, in SCC1483 and YD15PP2 HNSCC cell lines, PP2 exposure downregulated Erk, Akt/Slug, and Snail but upregulated E-cadherin. These results suggest that PP2 inhibits cell growth and progression in HNSCC by regulating the epithelial-mesenchymal transition pathway.

Precursor silanization assisted synthesis and optical tuning of dual-phase perovskite nanocrystals embedded in silica matrix with high environmental stability.

Ligand-assisted re-precipitation (LARP) is one of the most practicing techniques for synthesizing colloidal nanocrystals (NCs). But due to its fast reaction kinetics, it offers limited synthesis control. In the present study, we report a novel, precursor silanization-based room temperature technique unveiling slow crystallization of Cs4PbBr6/CsPbBr3 dual-phase nanocrystals (DPNCs) protected with a dense silica cloud-like matrix. Unlike conventional LARP, we can observe the tuneable optical bandgap of the DPNCs as a function of reaction time because of the slow reaction kinetics. The as-synthesized DPNCs exhibit a high photoluminescence quantum yield (PLQY) of 76% with ultrahigh stability while retaining âˆ¼ 100% of their initial PLQY in an ambient environment with a relative humidity of 55% for more than 1 year. DPNCs demonstrates ambient photostability of 560 h, and water stability of 25 days. This interesting precursor silanization technique developed here can be extended for the synthesis of other nanomaterials.

Copper cobalt tin sulphide (Cu2CoSnS4) anodes synthesised using a chemical route for stable and efficient rechargeable lithium-ion batteries.

In everyday life, superior lithium-ion batteries (LIBs), with fast charging ability, have become valuable assets. The LIB performance of an anode composite copper cobalt tin sulphide (Cu2CoSnS4; CCTS) electrode, which was fabricated using a simple and easy hydrothermal method, was investigated. The electrochemical charge storage performance of the CCTS anode demonstrated sustainability, high-rate capability and efficiency. The CCTS anode exhibited a first discharge capacity of 914.5 mA h g-1 and an average specific capacity of 198.7 mA h g-1 in consecutive cycles at a current density of 0.1 A g-1. It had a capacity retention of ∼62.0% and a coulombic efficiency of more than 83% after over 100 cycles, demonstrating its excellent cycling performance and reversibility. It can be an alternative anode to other established electrode materials for real battery applications.

rGO functionalized (Ni,Fe)-OH for an efficient trifunctional catalyst in low-cost hydrogen generation via urea decomposition as a proxy anodic reaction.

Green hydrogen derived from the water-electrolysis route is emerging as a game changer for achieving global carbon neutrality. Economically producing hydrogen through water electrolysis, however, requires the development of low-cost and highly efficient electrocatalysts via scalable synthetic strategies. Herein, this work reports a simple and scalable immersion synthetic strategy to deposit reduced graphene oxide (rGO) nanosheets integrated with Ni-Fe-based hydroxide nanocatalysts on nickel foam (NF) at room temperature. As a result of synergetic interactions among the hydroxides, rGO and NF, enhanced catalytic sites with improved charge transport between the electrode and electrolyte were perceived, resulting in significantly enhanced oxygen evolution reaction (OER) activity with low overpotentials of 270 and 320 mV at 100 and 500 mA cm-2, respectively, in a 1.0 M KOH aqueous electrolyte. This performance is superior to those of the hydroxide-based electrode without incorporating rGO and the IrO2-benchmark electrode. Furthermore, when the conventional OER is substituted with urea decomposition (UOR) as a proxy anodic reaction, the electrolyzer achieves 100 and 500 mA cm-2 at a lower potential by 150 and 120 mV, respectively than the OER counterpart without influencing the hydrogen evolution reaction (HER) activity at the cathode. Notably, the rGO-incorporated electrode delivers a spectacularly high UOR current density of 1600 mA cm-2 at 1.53 V vs. RHE, indicating the decomposition of urea at an outstandingly high rate.

Catalytic and Enantioselective Control of the C-N Stereogenic Axis via the Pictet-Spengler Reaction.

An unprecedented example of a chiral phosphoric acid-catalyzed atroposelective Pictet-Spengler reaction of N-arylindoles is reported. Highly enantioenriched N-aryl-tetrahydro-ß-carbolines with C-N bond axial chirality are obtained via dynamic kinetic resolution. The hydrogen bond donor introduced on the bottom aromatic ring, forming a secondary interaction with the phosphoryl oxygen, is essential to achieving high enantioselectivity. A wide variety of substituents are tolerable with this transformation to provide up to 98 % ee. The application of electron-withdrawing group-substituted benzaldehydes enables the control of both axial and point stereogenicity. Biological evaluation of this new and unique scaffold shows promising antiproliferative activity and emphasizes the significance of atroposelective synthesis.

Ependymal Cells Require Anks1a for Their Proper Development.

Ependymal cells constitute the multi-ciliated epithelium, which lines the brain ventricular lumen. Although ependymal cells originate from radial glial cells in the perinatal rodent brain, the exact mechanisms underlying the full differentiation of ependymal cells are poorly understood. In this report, we present evidence that the Anks1a phosphotyrosine binding domain (PTB) adaptor is required for the proper development of ependymal cells in the rodent postnatal brain. Anks1a gene trap targeted LacZ reporter analysis revealed that Anks1a is expressed prominently in the ventricular region of the early postnatal brain and that its expression is restricted to mature ependymal cells during postnatal brain development. In addition, Anks1a-deficient ependymal cells were shown to possess type B cell characteristics, suggesting that ependymal cells require Anks1a in order to be fully differentiated. Finally, Anks1a overexpression in the lateral wall of the neonatal brain resulted in an increase in the number of ependymal cells during postnatal brain development. Altogether, our results suggest that ependymal cells require Anks1a PTB adaptor for their proper development.

Types of Parenting of Fathers during Early Childhood: A Q Methodological Approach.

PURPOSE: The purpose of this study was to examine types of parenting among fathers. The characteristics of parenting each type in early childhood were identified by systematically analyzing and classifying father's perceptions of parenting using the Q-methodology, which places importance on the perspective of the performer. METHODS: The Q-method, which is effective for measuring individual subjectivity was used. The subjects in this study were 50 fathers with young children (2~36 months). RESULTS: Four parenting types were identified analyzing the subjective perceptions of fathers with young children about parenting. One type was centered on character development. Another was centered on social development. A third was centered on physical health and development. The fourth was centered on building values. CONCLUSION: Parenting education programs should be developed based on type-specific characteristics and further research should investigate the effects of father's parenting type.

Modulation of Neuroinflammation by Taklisodok-um in a Spinal Cord Injury Model.

OBJECTIVE: Chronic neuroinflammation after spinal cord injury (SCI) is associated with spinal cord damage and functional impairment. In patients, SCI is associated with severe disability, an extensive rehabilitation requirement, and high cost burden. Moreover, there is no effective treatment for SCI. Taklisodok-um (TLSDU) is a traditional herbal medicine used in Korea and China to facilitate detoxification and drainage. This study investigated the therapeutic effect of TLSDU after SCI. METHODS: Seven-week-old ICR mice (male, 20-30 g) underwent hemi-transection in the T9-10 segment of the spinal cord and were divided into 3 groups: sham, SCI + control treatment, and SCI + TLSDU treatment. TLSDU treatment was initiated the day after SCI surgery and administered once daily for 3 weeks at an oral dose of 1.2 mg/g. The mice were weighed for 3 weeks. At the age of 10 weeks, all mice were sacrificed and immunohistochemistry and Western blotting were performed. RESULTS: We found that TLSDU facilitated healthy weight gain and attenuated the expression of neuroinflammatory markers. GFAP and Iba-1 expression levels were downregulated in the spinal cords of TLSDU-treated SCI mice as compared to control SCI mice. Additionally, pro-inflammatory proteins CD11b and BAX were induced in control SCI mice, but their expression was attenuated in TLSDU-treated SCI mice. Finally, we found that the expression of TLR4 signaling pathway-related proteins was downregulated in TLSDU-treated SCI mice as compared to control SCI mice. CONCLUSION: These findings suggest that TLSDU attenuates neuroinflammation after SCI in part by regulating TLR4 signaling at the injury site.

Anti-Inflammatory Effect of Gamisoyo-San in an Animal Model of Amyotrophic Lateral Sclerosis.

Inflammation is considered a critical factor in the pathogenesis of amyotrophic lateral sclerosis (ALS). We aimed to evaluate the effect of the herbal formula Gamisoyo-San (GSS) on the muscles of hSOD1G93A transgenic mice, a mouse model of ALS, by examining the tissue expression of inflammation- and oxidative stress-related proteins. The mice were randomly divided into three groups: nontransgenic mice (non-Tg, n = 4), hSOD1G93A transgenic mice (Tg, n = 4), and GSS-treated hSOD1G93A transgenic mice (Tg+GSS, n = 4). Eight-week-old female hSOD1G93A transgenic mice were fed GSS (1 mg/g body weight) for 6 weeks. Gastrocnemius (GA) tissues were analyzed for inflammatory proteins [CD11b and toll-like receptor 4 (TLR4)] and oxidative stress-related proteins [heme oxygenase 1 (HO1) and ferritin] by western blot analysis. Administration of GSS significantly reduced the level of inflammation- and oxidative stress-related proteins in hSOD1G93A transgenic mice. GSS ameliorated inflammation by downregulating TLR4 and CD11b expression and regulated iron homeostasis in the GA muscle of hSOD1G93A mice. GSS could help reduce inflammation by regulating immune reactions in patients with ALS. To the best of our knowledge, this is the first study to demonstrate the effect of GSS on muscle inflammation in an ALS animal model.

Effects of Acupuncture on Alzheimer's Disease in Animal-Based Research.

Alzheimer's disease (AD) is a chronic neurodegenerative disease characterized by the accumulation of amyloid beta (Aß) plaques, neurofibrillary tangles, and severe functional deficits in the brain. The pathogenesis and treatment of AD remain topics of investigation and significant global socioeconomic issues. The effect of complementary medicine has been investigated in managing AD. Acupuncture, a form of therapy practiced for more than 3000 years, has shown positive effects on several neurological disorders including AD. Animal studies have evaluated the specific utility and neuropathological mechanisms addressed by acupoint manipulation; however, no study has summarized the relationships among different acupoints and their therapeutic effects in the context of AD. Therefore, we reviewed the effects of acupuncture at different acupoints in animal models of AD. In general, acupuncture produced therapeutic benefits in rodent models of AD. Studies demonstrate the utility of GV20 as a valuable acupoint for electroacupuncture and manual acupuncture. GV20 stimulation suppresses Aß generation, improves glucose metabolism, and attenuates neuropathological features in various disease models. However, a lack of sufficient evidence in preclinical and clinical studies makes these results controversial. Additional studies are required to confirm the exact utility of specific acupoints in clinically managing AD.

Arabidopsis lipid droplet-associated protein (LDAP) - interacting protein (LDIP) influences lipid droplet size and neutral lipid homeostasis in both leaves and seeds.

Cytoplasmic lipid droplets (LDs) are found in all types of plant cells; they are derived from the endoplasmic reticulum and function as a repository for neutral lipids, as well as serving in lipid remodelling and signalling. However, the mechanisms underlying the formation, steady-state maintenance and turnover of plant LDs, particularly in non-seed tissues, are relatively unknown. Previously, we showed that the LD-associated proteins (LDAPs) are a family of plant-specific, LD surface-associated coat proteins that are required for proper biogenesis of LDs and neutral lipid homeostasis in vegetative tissues. Here, we screened a yeast two-hybrid library using the Arabidopsis LDAP3 isoform as 'bait' in an effort to identify other novel LD protein constituents. One of the candidate LDAP3-interacting proteins was Arabidopsis At5g16550, which is a plant-specific protein of unknown function that we termed LDIP (LDAP-interacting protein). Using a combination of biochemical and cellular approaches, we show that LDIP targets specifically to the LD surface, contains a discrete amphipathic α-helical targeting sequence, and participates in both homotypic and heterotypic associations with itself and LDAP3, respectively. Analysis of LDIP T-DNA knockdown and knockout mutants showed a decrease in LD abundance and an increase in variability of LD size in leaves, with concomitant increases in total neutral lipid content. Similar phenotypes were observed in plant seeds, which showed enlarged LDs and increases in total amounts of seed oil. Collectively, these data identify LDIP as a new player in LD biology that modulates both LD size and cellular neutral lipid homeostasis in both leaves and seeds.

Effects of pre-education combined with a simulation for caring for children with croup on senior nursing students.

Educational outcomes, such as knowledge, confidence in performance, ability in nursing practice, and satisfaction with learning methods in caring for children with croup, were compared between groups of students that received education through simulation combined with pre-education, simulation only, and pre-education only. In this quasi-experimental design, the educational intervention for the experimental group was the pre-education modality. Data from a convenience sample of 127 senior nursing students were drawn from three nursing schools in South Korea. There were significant differences in the mean scores of knowledge, confidence in performance, satisfaction with the learning method, and ability in nursing practice between the three groups. Pre-education with simulation significantly enhanced students' knowledge, confidence in performance, ability in nursing practice, and satisfaction with learning methods compared with pre-education or simulation alone. Simulation strategies should focus more on enhancing nursing students' learning outcomes.

Mouse fat storage-inducing transmembrane protein 2 (FIT2) promotes lipid droplet accumulation in plants.

Fat storage-inducing transmembrane protein 2 (FIT2) is an endoplasmic reticulum (ER)-localized protein that plays an important role in lipid droplet (LD) formation in animal cells. However, no obvious homologue of FIT2 is found in plants. Here, we tested the function of FIT2 in plant cells by ectopically expressing mouse (Mus musculus) FIT2 in Nicotiana tabacum suspension-cultured cells, Nicotiana benthamiana leaves and Arabidopsis thaliana plants. Confocal microscopy indicated that the expression of FIT2 dramatically increased the number and size of LDs in leaves of N. benthamiana and Arabidopsis, and lipidomics analysis and mass spectrometry imaging confirmed the accumulation of neutral lipids in leaves. FIT2 also increased seed oil content by ~13% in some stable, overexpressing lines of Arabidopsis. When expressed transiently in leaves of N. benthamiana or suspension cells of N. tabacum, FIT2 localized specifically to the ER and was often concentrated at certain regions of the ER that resembled ER-LD junction sites. FIT2 also colocalized at the ER with other proteins known to be involved in triacylglycerol biosynthesis or LD formation in plants, but not with ER resident proteins involved in electron transfer or ER-vesicle exit sites. Collectively, these results demonstrate that mouse FIT2 promotes LD accumulation in plants, a surprising functional conservation in the context of a plant cell given the apparent lack of FIT2 homologues in higher plants. These results suggest also that FIT2 expression represents an effective synthetic biology strategy for elaborating neutral lipid compartments in plant tissues for potential biofuel or bioproduct purposes.

Lipid Droplet-Associated Proteins (LDAPs) Are Required for the Dynamic Regulation of Neutral Lipid Compartmentation in Plant Cells.

Eukaryotic cells compartmentalize neutral lipids into organelles called lipid droplets (LDs), and while much is known about the role of LDs in storing triacylglycerols in seeds, their biogenesis and function in nonseed tissues are poorly understood. Recently, we identified a class of plant-specific, lipid droplet-associated proteins (LDAPs) that are abundant components of LDs in nonseed cell types. Here, we characterized the three LDAPs in Arabidopsis (Arabidopsis thaliana) to gain insight to their targeting, assembly, and influence on LD function and dynamics. While all three LDAPs targeted specifically to the LD surface, truncation analysis of LDAP3 revealed that essentially the entire protein was required for LD localization. The association of LDAP3 with LDs was detergent sensitive, but the protein bound with similar affinity to synthetic liposomes of various phospholipid compositions, suggesting that other factors contributed to targeting specificity. Investigation of LD dynamics in leaves revealed that LD abundance was modulated during the diurnal cycle, and characterization of LDAP misexpression mutants indicated that all three LDAPs were important for this process. LD abundance was increased significantly during abiotic stress, and characterization of mutant lines revealed that LDAP1 and LDAP3 were required for the proper induction of LDs during heat and cold temperature stress, respectively. Furthermore, LDAP1 was required for proper neutral lipid compartmentalization and triacylglycerol degradation during postgerminative growth. Taken together, these studies reveal that LDAPs are required for the maintenance and regulation of LDs in plant cells and perform nonredundant functions in various physiological contexts, including stress response and postgerminative growth.

In Vivo Expression of the PTB-deleted Odin Mutant Results in Hydrocephalus.

Odin has been implicated in the downstream signaling pathway of receptor tyrosine kinases, such as the epidermal growth factor and Eph receptors. However, the physiologically relevant function of Odin needs to be further determined. In this study, we used Odin heterozygous mice to analyze the Odin expression pattern; the targeted allele contained a ß-geo gene trap vector inserted into the 14th intron of the Odin gene. Interestingly, we found that Odin was exclusively expressed in ependymal cells along the brain ventricles. In particular, Odin was highly expressed in the subcommissural organ, a small ependymal glandular tissue. However, we did not observe any morphological abnormalities in the brain ventricles or ependymal cells of Odin null-mutant mice. We also generated BAC transgenic mice that expressed the PTB-deleted Odin (dPTB) after a floxed GFP-STOP cassette was excised by tissue-specific Cre expression. Strikingly, Odin-dPTB expression played a causative role in the development of the hydrocephalic phenotype, primarily in the midbrain. In addition, Odin-dPTB expression disrupted proper development of the subcommissural organ and interfered with ependymal cell maturation in the cerebral aqueduct. Taken together, our findings strongly suggest that Odin plays a role in the differentiation of ependymal cells during early postnatal brain development.

EphA receptors form a complex with caspase-8 to induce apoptotic cell death.

EphA7 has been implicated in the regulation of apoptotic cell death in neural epithelial cells. In this report, we provide evidence that EphA7 interacts with caspase-8 to induce apoptotic cell signaling. First, a pull-down assay using biotinylated ephrinA5-Fc showed that EphA7 coprecipitated with wild type caspase-8 or catalytically inactive caspase-8 mutant. Second, co-transfection of EphA7 with caspase-8 significantly increased the number of cleaved caspase-3 positive apoptotic cells under an experimental condition where transfection of EphA7 or caspase-8 alone did not affect cell viability or apoptosis. EphA4 also had a causative role in inducing apoptotic cell death with caspase-8, whereas EphA8 did not. Third, caspase-8 catalytic activity was essential for the apoptotic signaling cascade, whereas tyrosine kinase activity of the EphA4 receptor was not. Interestingly, we found that kinaseinactive EphA4 was well co-localized at the plasma membrane with catalytically inactive caspase-8, suggesting that an interaction between these mutant proteins was more stable. Finally, we observed that the extracellular region of the EphA7 receptor was critical for interacting with caspase-8, whereas the cytoplasmic region of EphA7 was not. Therefore, we propose that Eph receptors physically associate with a transmembrane protein to form an apoptotic signaling complex and that this unidentified receptorlike protein acts as a biochemical linker between the Eph receptor and caspase-8.

Genome-wide analysis of the omega-3 fatty acid desaturase gene family in Gossypium.

BACKGROUND: The majority of commercial cotton varieties planted worldwide are derived from Gossypium hirsutum, which is a naturally occurring allotetraploid produced by interspecific hybridization of A- and D-genome diploid progenitor species. While most cotton species are adapted to warm, semi-arid tropical and subtropical regions, and thus perform well in these geographical areas, cotton seedlings are sensitive to cold temperature, which can significantly reduce crop yields. One of the common biochemical responses of plants to cold temperatures is an increase in omega-3 fatty acids, which protects cellular function by maintaining membrane integrity. The purpose of our study was to identify and characterize the omega-3 fatty acid desaturase (FAD) gene family in G. hirsutum, with an emphasis on identifying omega-3 FADs involved in cold temperature adaptation. RESULTS: Eleven omega-3 FAD genes were identified in G. hirsutum, and characterization of the gene family in extant A and D diploid species (G. herbaceum and G. raimondii, respectively) allowed for unambiguous genome assignment of all homoeologs in tetraploid G. hirsutum. The omega-3 FAD family of cotton includes five distinct genes, two of which encode endoplasmic reticulum-type enzymes (FAD3-1 and FAD3-2) and three that encode chloroplast-type enzymes (FAD7/8-1, FAD7/8-2, and FAD7/8-3). The FAD3-2 gene was duplicated in the A genome progenitor species after the evolutionary split from the D progenitor, but before the interspecific hybridization event that gave rise to modern tetraploid cotton. RNA-seq analysis revealed conserved, gene-specific expression patterns in various organs and cell types and semi-quantitative RT-PCR further revealed that FAD7/8-1 was specifically induced during cold temperature treatment of G. hirsutum seedlings. CONCLUSIONS: The omega-3 FAD gene family in cotton was characterized at the genome-wide level in three species, showing relatively ancient establishment of the gene family prior to the split of A and D diploid progenitor species. The FAD genes are differentially expressed in various organs and cell types, including fiber, and expression of the FAD7/8-1 gene was induced by cold temperature. Collectively, these data define the genetic and functional genomic properties of this important gene family in cotton and provide a foundation for future efforts to improve cotton abiotic stress tolerance through molecular breeding approaches.

CGI-58, a key regulator of lipid homeostasis and signaling in plants, also regulates polyamine metabolism.

Comparative Gene Identification-58 (CGI-58) is an α/ß hydrolase-type protein that regulates lipid homeostasis and signaling in eukaryotes by interacting with and stimulating the activity of several different types of proteins, including a lipase in mammalian cells and a peroxisomal ABC transporter (PXA1) in plant cells. Here we show that plant CGI-58 also interacts with spermidine synthase 1 (SPDS1), an enzyme that plays a central role in polyamine metabolism by converting putrescine into spermidine. Analysis of polyamine contents in Arabidopsis thaliana plants revealed that spermidine levels were significantly reduced, and putrescine increased, in both cgi-58 and cgi-58/pxa1 mutant plants, relative to pxa1 mutant or wild-type plants. Evaluation of polyamine-related gene expression levels, however, revealed similar increases in transcript abundance in all mutants, including cgi-58, pxa1, and cgi-58/pxa1, in comparison to wild type. Taken together, the data support a model whereby CGI-58 and PXA1 contribute to the regulation of polyamine metabolism at the transcriptional level, perhaps through a shared lipid-signaling pathway, and that CGI-58 also acts independently of PXA1 to increase spermidine content at a post-transcriptional level, possibly through protein-protein interaction with SPDS1.

[Types of child rearing behavior of parents during early childhood: Q-methodological approach].

PURPOSE: The purpose of this study was to identify the awareness of child rearing among parents of children in early childhood and to provide fundamental data for parent education programs according to child rearing type. METHODS: Q-methodology which provides a method of analyzing the subjectivity of each item was used. Forty Q items which were derived from a literature review and interviews with nurturing mothers were classified into a normal distribution using a 9-point scale. Collected data were analyzed using the QUANAL PC Program. RESULTS: Four types of parents' child rearing were identified. Type I was named 'affection-respect type', type II, 'concern-rule compliant type', type III, 'solicitude-model type', and type IV, 'geniality-encouragement type'. CONCLUSION: For proper growth and development during early childhood, parents should have rational information and awareness of their child rearing type. Results of this study can be used as essential data to develop child rearing education programs according to parents' child rearing attitude.

The α/ß hydrolase CGI-58 and peroxisomal transport protein PXA1 coregulate lipid homeostasis and signaling in Arabidopsis.

COMPARATIVE GENE IDENTIFICATION-58 (CGI-58) is a key regulator of lipid metabolism and signaling in mammals, but its underlying mechanisms are unclear. Disruption of CGI-58 in either mammals or plants results in a significant increase in triacylglycerol (TAG), suggesting that CGI-58 activity is evolutionarily conserved. However, plants lack proteins that are important for CGI-58 activity in mammals. Here, we demonstrate that CGI-58 functions by interacting with the PEROXISOMAL ABC-TRANSPORTER1 (PXA1), a protein that transports a variety of substrates into peroxisomes for their subsequent metabolism by ß-oxidation, including fatty acids and lipophilic hormone precursors of the jasmonate and auxin biosynthetic pathways. We also show that mutant cgi-58 plants display changes in jasmonate biosynthesis, auxin signaling, and lipid metabolism consistent with reduced PXA1 activity in planta and that, based on the double mutant cgi-58 pxa1, PXA1 is epistatic to CGI-58 in all of these processes. However, CGI-58 was not required for the PXA1-dependent breakdown of TAG in germinated seeds. Collectively, the results reveal that CGI-58 positively regulates many aspects of PXA1 activity in plants and that these two proteins function to coregulate lipid metabolism and signaling, particularly in nonseed vegetative tissues. Similarities and differences of CGI-58 activity in plants versus animals are discussed.