Distinct landscape and clinical implications of therapy-related clonal hematopoiesis.

Therapy-related clonal hematopoiesis (t-CH) is defined as clonal hematopoiesis detected in individuals previously treated with chemotherapy and/or radiation therapy. With the increased use of genetic analysis in oncological care, the detection of t-CH among cancer patients is becoming increasingly common. t-CH arises through the selective bottleneck imposed by chemotherapies and potentially through direct mutagenesis from chemotherapies, resulting in a distinct mutational landscape enriched with mutations in DNA damage-response pathway genes such as TP53, PPM1D, and CHEK2. Emerging evidence sheds light on the mechanisms of t-CH development and potential strategies to mitigate its emergence. Due to its unique characteristics that predominantly affect cancer patients, t-CH has clinical implications distinct from those of CH in the general population. This Review discusses the potential mechanisms of t-CH development, its mutational landscape, mutant-drug relationships, and its clinical significance. We highlight the distinct nature of t-CH and call for intensified research in this field.

PPM1G and its diagnostic, prognostic and therapeutic potential in HCC (Review).

Global statistics indicate that hepatocellular carcinoma (HCC) is the sixth most common cancer and the third leading cause of cancer­related death. Protein phosphatase Mg2+/Mn2+ dependent 1G (PPM1G, also termed PP2Cγ) is one of the 17 members of the PPM family. The enzymatic activity of PPM1G is highly reliant on Mg2+ or Mn2+ and serves as a dephosphorylation regulator for numerous key proteins. PPM1G, functioning as a phosphatase, is involved in a number of significant biological processes such as the regulation of eukaryotic gene expression, DNA damage response, cell cycle and apoptosis, cell migration ability, cell survival and embryonic nervous system development. Additionally, PPM1G serves a role in regulating various signaling pathways. In recent years, further research has increasingly highlighted PPM1G as an oncogene in HCC. A high expression level of PPM1G is closely associated with the occurrence, progression and poor prognosis of HCC, offering notable diagnostic and therapeutic value for this patient population. In the present review, the regulatory role of PPM1G in diverse biological processes and signaling pathway activation in eukaryotes is evaluated. Furthermore, its potential application as a biomarker in the diagnosis and prognosis evaluation of HCC is assessed, and future prospects for HCC treatment strategies centered on PPM1G are discussed.

PPM1D activity promotes cellular transformation by preventing senescence and cell death.

Cell cycle checkpoints, oncogene-induced senescence and programmed cell death represent intrinsic barriers to tumorigenesis. Protein phosphatase magnesium-dependent 1 (PPM1D) is a negative regulator of the tumour suppressor p53 and has been implicated in termination of the DNA damage response. Here, we addressed the consequences of increased PPM1D activity resulting from the gain-of-function truncating mutations in exon 6 of the PPM1D. We show that while control cells permanently exit the cell cycle and reside in senescence in the presence of DNA damage caused by ionising radiation or replication stress induced by the active RAS oncogene, RPE1-hTERT and BJ-hTERT cells carrying the truncated PPM1D continue proliferation in the presence of DNA damage, form micronuclei and accumulate genomic rearrangements revealed by karyotyping. Further, we show that increased PPM1D activity promotes cell growth in the soft agar and formation of tumours in xenograft models. Finally, expression profiling of the transformed clones revealed dysregulation of several oncogenic and tumour suppressor pathways. Our data support the oncogenic potential of PPM1D in the context of exposure to ionising radiation and oncogene-induced replication stress.

Comprehensive genomic analysis of CiPawPYL-PP2C-SnRK family genes in pecan (Carya illinoinensis) and functional characterization of CiPawSnRK2.1 under salt stress responses.

Abscisic acid (ABA) is a pivotal regulator of plant growth, development, and responses to environmental stresses. The ABA signaling pathway involves three key components: ABA receptors known as PYLs, PP2Cs, and SnRK2s, which are conserved across higher plants. This study comprehensively investigated the PYL-PP2C-SnRK gene family in pecan, identifying 14 PYL genes, 97 PP2C genes, and 44 SnRK genes, which were categorized into subgroups through phylogenetic and sequence structure analysis. Whole-genome duplication (WGD) and dispersed duplication (DSD) were identified as major drivers of family expansion, and purifying selection was the primary evolutionary force. Tissue-specific expression analysis suggested diverse functions in different pecan tissues. qRT-PCR validation confirmed the involvement of CiPawPYLs, CiPawPP2CAs, and CiPawSnRK2s in salt stress response. Subcellular localization analysis revealed CiPawPP2C1 in the nucleus and CiPawPYL1 and CiPawSnRK2.1 in both the nucleus and the plasma membrane. In addition, VIGS indicated that CiPawSnRK2.1-silenced pecan seedling leaves display significantly reduced salt tolerance. Y2H and LCI assays verified that CiPawPP2C3 can interact with CiPawPYL5, CiPawPYL8, and CiPawSnRK2.1. This study characterizes the role of CiPawSnRK2.1 in salt stress and lays the groundwork for exploring the CiPawPYL-PP2C-SnRK module, highlighting the need to investigate the roles of other components in the pecan ABA signaling pathway.

PPM1G promotes autophagy and progression of pancreatic cancer via upregulating HMGB1.

Pancreatic cancer remains one of the most aggressive and lethal malignancies worldwide, with a dismal 5-year relative survival rates of only 12%. Therefore, it is urgent to discover the key molecular markers to improve the therapeutic outcomes in pancreatic cancer. Herein, we first demonstrated that PPM1G is upregulated in pancreatic cancer and that PPM1G depletion decreases pancreatic cancer cell growth in vitro and in vivo. High PPM1G expression was linked to short overall survival of pancreatic cancer patients, which was further validated in the TCGA database. Moreover, by detecting Beclin 1, LC3-II, and SQSTM1/p62 expressions and observing autolysosome under transmission electron microscope, we discovered that PPM1G is a novel positive regulator of macroautophagy/autophagy. Furthermore, by using immunoprecipitation-mass spectrometry (IP-MS) analysis and following systemic molecular biology experiment, we demonstrated PPM1G promotes the autophagy and proliferation of pancreatic cancer by directly upregulating HMGB1. Additionally, patients with both high PPM1G and high HMGB1 exhibited poorer prognosis in our cohort. This study preliminarily investigated the possibility of PPM1G as a potential therapeutic target and prognostic biomarker in pancreatic cancer patients.

Genome-wide analysis of the PYL-PP2C-SnRK2s family in the ABA signaling pathway of pitaya reveals its expression profiles under canker disease stress.

BACKGROUND: Abscisic acid (ABA) plays a crucial role in seed dormancy, germination, and growth, as well as in regulating plant responses to environmental stresses during plant growth and development. However, detailed information about the PYL-PP2C-SnRK2s family, a central component of the ABA signaling pathway, is not known in pitaya. RESULTS: In this study, we identified 19 pyrabactin resistance-likes (PYLs), 70 type 2 C protein phosphatases (PP2Cs), and 14 SNF1-related protein kinase 2s (SnRK2s) from pitaya. In pitaya, tandem duplication was the primary mechanism for amplifying the PYL-PP2C-SnRK2s family. Co-linearity analysis revealed more homologous PYL-PP2C-SnRK2s gene pairs located in collinear blocks between pitaya and Beta vulgaris L. than that between pitaya and Arabidopsis. Transcriptome analysis showed that the PYL-PP2C-SnRK2s gene family plays a role in pitaya's response to infection by N. dimidiatum. By spraying ABA on pitaya and subsequently inoculating it with N. dimidiatum, we conducted qRT-PCR experiments to observe the response of the PYL-PP2C-SnRK2s gene family and disease resistance-related genes to ABA. These treatments significantly enhanced pitaya's resistance to pitaya canker. Further protein interaction network analysis helped us identify five key PYLs genes that were upregulated during the interaction between pitaya and N. dimidiatum, and their expression patterns were verified by qRT-PCR. Subcellular localization analysis revealed that the PYL (Hp1879) gene is primarily distributed in the nucleus. CONCLUSION: This study enhances our understanding of the response of PYL-PP2C-SnRK2s to ABA and also offers a new perspective on pitaya disease resistance.

PPM1G dephosphorylates eIF4E in control of mRNA translation and cell proliferation.

The mRNA 5'cap-binding eukaryotic translation initiation factor 4E (eIF4E) plays a critical role in the control of mRNA translation in health and disease. One mechanism of regulation of eIF4E activity is via phosphorylation of eIF4E by MNK kinases, which promotes the translation of a subset of mRNAs encoding pro-tumorigenic proteins. Work on eIF4E phosphatases has been paltry. Here, we show that PPM1G is the phosphatase that dephosphorylates eIF4E. We describe the eIF4E-binding motif in PPM1G that is similar to 4E-binding proteins (4E-BPs). We demonstrate that PPM1G inhibits cell proliferation by targeting phospho-eIF4E-dependent mRNA translation.

Short-Term Statin Therapy Induces Hepatic Insulin Resistance Through HNF4α/PAQR9/PPM1α Axis Regulated AKT Phosphorylation.

Statins, the first-line medication for dyslipidemia, are linked to an increased risk of type 2 diabetes. But exactly how statins cause diabetes is yet unknown. In this study, a developed short-term statin therapy on hyperlipidemia mice show that hepatic insulin resistance is a cause of statin-induced diabetes. Statin medication raises the expression of progesterone and adiponectin receptor 9 (PAQR9) in liver, which inhibits insulin signaling through degradation of protein phosphatase, Mg2+/Mn2+ dependent 1 (PPM1α) to activate ERK pathway. STIP1 homology and U-box containing protein 1 (STUB1) is found to mediate ubiquitination of PPM1α promoted by PAQR9. On the other hand, decreased activity of hepatocyte nuclear factor 4 alpha (HNF4α) seems to be the cause of PAQR9 expression under statin therapy. The interventions on PAQR9, including deletion of PAQR9, caloric restriction and HNF4α activation, are all effective treatments for statin-induced diabetes, while liver specific over-expression of PPM1α is another possible tactic. The results reveal the importance of HNF4α-PAQR9-STUB1-PPM1α axis in controlling the statin-induced hepatic insulin resistance, offering a fresh insight into the molecular mechanisms underlying statin therapy.

Crystal structure and mechanistic studies of the PPM1D serine/threonine phosphatase catalytic domain.

Protein phosphatase 1D (PPM1D, Wip1) is induced by the tumor suppressor p53 during DNA damage response signaling and acts as an oncoprotein in several human cancers. Although PPM1D is a potential therapeutic target, insights into its atomic structure were challenging due to flexible regions unique to this family member. Here, we report the first crystal structure of the PPM1D catalytic domain to 1.8 Å resolution. The structure reveals the active site with two Mg2+ ions bound, similar to other structures. The flap subdomain and B-loop, which are crucial for substrate recognition and catalysis, were also resolved, with the flap forming two short helices and three short ß-strands that are followed by an irregular loop. Unexpectedly, a nitrogen-oxygen-sulfur bridge was identified in the catalytic domain. Molecular dynamics simulations and kinetic studies provided further mechanistic insights into the regulation of PPM1D catalytic activity. In particular, the kinetic experiments demonstrated a magnesium concentration-dependent lag in PPM1D attaining steady-state velocity, a feature of hysteretic enzymes that show slow transitions compared with catalytic turnover. All combined, these results advance the understanding of PPM1D function and will support the development of PPM1D-targeted therapeutics.

Genome-wide identification and expression analysis of the PP2C gene family in Apocynum venetum and Apocynum hendersonii.

BACKGROUND: Protein phosphatase class 2 C (PP2C) is the largest protein phosphatase family in plants. Members of the PP2C gene family are involved in a variety of physiological pathways in plants, including the abscisic acid signalling pathway, the regulation of plant growth and development, etc., and are capable of responding to a wide range of biotic and abiotic stresses, and play an important role in plant growth, development, and response to stress. Apocynum is a perennial persistent herb, divided into Apocynum venetum and Apocynum hendersonii. It mainly grows in saline soil, deserts and other harsh environments, and is widely used in saline soil improvement, ecological restoration, textiles and medicine. A. hendersonii was found to be more tolerant to adverse conditions. The main purpose of this study was to investigate the PP2C gene family and its expression pattern under salt stress and to identify important candidate genes related to salt tolerance. RESULTS: In this study, 68 AvPP2C genes and 68 AhPP2C genes were identified from the genomes of A. venetum and A. hendersonii, respectively. They were classified into 13 subgroups based on their phylogenetic relationships and were further analyzed for their subcellular locations, gene structures, conserved structural domains, and cis-acting elements. The results of qRT-PCR analyses of seven AvPP2C genes and seven AhPP2C genes proved that they differed significantly in gene expression under salt stress. It has been observed that the PP2C genes in A. venetum and A. hendersonii exhibit different expression patterns. Specifically, AvPP2C2, 6, 24, 27, 41 and AhPP2C2, 6, 24, 27, 42 have shown significant differences in expression under salt stress. This indicates that these genes may play a crucial role in the salt tolerance mechanism of A. venetum and A. hendersonii. CONCLUSIONS: In this study, we conducted a genome-wide analysis of the AvPP2C and AhPP2C gene families in Apocynum, which provided a reference for further understanding the functional characteristics of these genes.

Small Molecule Targeting PPM1A Activates Autophagy for Mycobacterium tuberculosis Host-Directed Therapy.

Mycobacterium tuberculosis (Mtb), the infectious agent of tuberculosis (TB), causes over 1.5 million deaths globally every year. Host-directed therapies (HDT) for TB are desirable for their potential to shorten treatment and reduce the development of antibiotic resistance. Previously, we described a modular biomimetic strategy to identify SMIP-30, targeting PPM1A (IC50 = 1.19 µM), a metal-dependent phosphatase exploited by Mtb to survive intracellularly. SMIP-30 restricted the survival of Mtb in macrophages and lungs of infected mice. Herein, we redesigned SMIP-30 to create SMIP-031, which is a more potent inhibitor for PPM1A (IC50 = 180 nM). SMIP-031 efficiently increased the level of phosphorylation of S403-p62 and the expression of LC3B-II to activate autophagy, resulting in the dose-dependent clearance of Mtb in infected macrophages. SMIP-031 possesses a good pharmacokinetic profile and oral bioavailability (F = 74%). In vivo, SMIP-031 is well tolerated up to 50 mg/kg and significantly reduces the bacteria burden in the spleens of infected mice.

Genome-wide identification, phylogenetic, structural and functional evolution of the core components of ABA signaling in plant species: a focus on rice.

MAIN CONCLUSION: A genome-wide analysis had identified 642 ABA core component genes from 20 plant species, which were further categorized into three distinct subfamilies. The gene structures and evolutionary relationships of these genes had been characterized. PP2C_1, PP2C_2, and SnRK2_1 had emerged as key players in mediating the ABA signaling transduction pathway, specifically in rice, in response to abiotic stresses. The plant hormone abscisic acid (ABA) is essential for growth, development, and stress response, relying on its core components, pyrabactin resistance, pyrabactin resistance-like, and the regulatory component of ABA receptor (PYR/PYL/RCAR), 2C protein phosphatase (PP2C), sucrose non-fermenting-1-related protein kinase 2 (SnRK2). However, there's a lack of research on their structural evolution and functional differentiation across plants. Our study analyzed the phylogenetic, gene structure, homology, and duplication evolution of this complex in 20 plant species. We found conserved patterns in copy number and homology across subfamilies. Segmental and tandem duplications drove the evolution of these genes, while whole-genome duplication (WGD) expanded PYR/PYL/RCAR and PP2C subfamilies, enhancing environmental adaptation. In rice and Arabidopsis, the PYR/PYL/RCAR, PP2C, and SnRK2 genes showed distinct tissue-specific expression and responded to various stresses. Notably, PP2C_1 and PP2C_2 interacted with SnRK2_1 and were crucial for ABA signaling in rice. These findings offered new insights into ABA signaling evolution, interactions, and integration in green plants, benefiting future research in agriculture, evolutionary biology, ecology, and environmental science.

[miR-342-3p Promotes the Proliferation, Migration, and Invasion of Clear Cell Renal Cell Carcinoma Cells by Targeted Inhibition of PPM1E]. / miR-342-3p通过靶向抑制PPM1E促进肾透明细胞癌细胞的增殖、迁移和侵袭.

Objective: To explore the effects of microRNA-342-3p/Mg2+Mn2+-dependent protein phosphatase 1E (miR-342-3p/PPM1E) on the proliferation, migration, and invasion of clear cell renal cell carcinoma (ccRCC) cells. Methods: The gene chips GSE12105, GSE23085, GSE66271, and GSE66270 were searched, and the relationship between miR-342-3p, PPM1E, and the clinical malignant phenotypes of ccRCC was analyzed. ACHN and 769-P cells were transfected with miR-342-3p inhibitor. The effects of miR-342-3p on cell proliferation, migration, and invasion were examined. ACHN cell line with stable and high expression of miR-342-3p was constructed, and the tumorigenicity of the cell line in BALB/c nude mice was observed. The targeted relationship between miR-342-3p and PPM1E was verified by dual-luciferase reporter gene assay. The cells were transfected with miR-342-3p mimic and pcDNA-PPM1E plasmids to observe whether PPM1E could reverse the effects of miR-342-3p overexpression on the proliferation, migration, and invasion of the cells. Results: The expression of miR-342-3p was upregulated in ccRCC, and there were significant differences among patients with tumors of different T stages and G stages and those with different prognoses (P<0.05). The overall survival in the miR-342-3p high-expression group was significantly shorter than that in the low-expression group (P<0.05). Compared with those in the miR-NC group, the miR-342-3p level was significantly downregulated in the inhibitor group, and the cell proliferation ability and the numbers of migrating and invading cells were also significantly decreased (P<0.05). Compared with the miR-NC group, miR-342-3p group had significantly increased volume and mass of tumor tissues and miR-342-3p level, but significantly decreased level of PPM1E mRNA (P<0.05). The expression of PPM1E was downregulated in ccRCC, and there were significant differences among patients with tumors of different M stages, N stages, and G stages, and different recurrence statuses (P<0.05). The miR-342-3p could inhibit the expression of PPM1E in a targeted way. Compared with the miR-NC group, the miR-342-3p group had significantly increased cell proliferation ability and increased numbers of migrating and invading cells (P<0.05). However, PPM1E could reverse the promotion effect of miR-342-3p mimic on ccRCC cells (P<0.05). Conclusion: The miR-342-3p can inhibit PPM1E expression in a targeted way, and thus promotes the proliferation, migration, and invasion of ccRCC cells.

WIP1-mediated regulation of p38 MAPK signaling attenuates pyroptosis in sepsis-associated acute kidney injury.

Wild-Type p53-Induced Phosphatase 1 (WIP1/PPM1D) is a serine/threonine phosphatase that plays a significant role in various physiological processes. However, the involvement of WIP1 in kidney remains unclear. Lipopolysaccharide (LPS) was administered to induce acute injury in mice and human kidney 2 (HK2) cells in the study. The WIP1 inhibitor, CCT007093, was administered both in vitro and in vivo to assess its effect on kidney. The single-cell sequencing (scRNA-seq) data revealed that Ppm1d mRNA reached peak on day 2 following unilateral ischemia-reperfusion injury (uni-IRI) in mice, especially in the proximal renal tubules during repair phase. Compared to the control group, WIP1 protein exhibited a significant increase in renal tubules of patients with acute tubular injury (ATI) and mice with LPS-induced acute kidney injury (AKI), as well as in LPS-injured HK2 cells. In vitro experiments showed that CCT007093 increased the protein levels of NLRP3, cleaved-Caspase1, GSDMD-N and IL-1ß in HK2 cells and further reduced the viability of LPS-stimulated HK2 cells. In vivo experiments showed that inhibition of WIP1 activity with CCT007093 further increased cleaved-Caspase1, GSDMD-N protein levels in kidney tissue from mice with LPS-induced AKI. In addition, LPS induces phosphorylation of p38 MAPK, a key regulator of pyroptosis, which is further activated by CCT007093. In conclusion, inhibition of WIP1 activity acts as a positive regulator of renal tubular pyroptosis mainly through the mediation of phospho-p38 MAPK.

Role of TRIM59 in regulating PPM1A in the pathogenesis of silicosis and the intervention effect of tanshinone IIA.

This study examines the involvement of TRIM59 in silica-induced pulmonary fibrosis and explores the therapeutic efficacy of Tanshinone IIA (Tan IIA). In vivo experiments conducted on rats with silica-induced pulmonary fibrosis unveiled an increase in TRIM59 levels and a decrease in PPM1A levels. Subsequent investigations using in vitro silicosis cell models demonstrated that modulation of TRIM59 expression significantly impacts silicosis fibrosis, influencing the levels of PPM1A and activation of the Smad2/3 signaling pathway. Immunofluorescence and co-immunoprecipitation assays confirmed the interaction between TRIM59 and PPM1A in fibroblasts, wherein TRIM59 facilitated the degradation of PPM1A protein via proteasomal and ubiquitin-mediated pathways. Furthermore, employing a rat model of silica-induced pulmonary fibrosis, Tan IIA exhibited efficacy in mitigating lung tissue damage and fibrosis. Immunohistochemical analysis validated the upregulation of TRIM59 and downregulation of PPM1A in silica-induced pulmonary fibrosis, which Tan IIA alleviated. In vitro studies elucidated the mechanism by which Tan IIA regulates the Smad2/3 signaling pathway through TRIM59-mediated modulation of PPM1A. Treatment with Tan IIA in silica-induced fibrosis cell models resulted in concentration-dependent reductions in fibrotic markers and attenuation of relevant protein expressions. Tan IIA intervention in silica-induced fibrosis cell models mitigated the TRIM59-induced upregulation of fibrotic markers and enhanced PPM1A expression, thereby partially reversing Smad2/3 activation. Overall, the findings indicate that while overexpression of TRIM59 may activate the Smads pathway by suppressing PPM1A expression, treatment with Tan IIA holds promise in counteracting these effects by inhibiting TRIM59 expression.

Identification of PP2Cs in six rosaceae species highlights RcPP2C24 as a negative regulator in rose drought tolerance.

Drought is a major environmental stress that limits plant growth, so it's important to identify drought-responsive genes to understand the mechanism of drought response and breed drought-tolerant roses. Protein phosphatase 2C (PP2C) plays a crucial role in plant abiotic stress response. In this study, we identified 412 putative PP2Cs from six Rosaceae species. These genes were divided into twelve clades, with clade A containing the largest number of PP2Cs (14.1%). Clade A PP2Cs are known for their important role in ABA-mediated drought stress response; therefore, the analysis focused on these specific genes. Conserved motif analysis revealed that clade A PP2Cs in these six Rosaceae species shared conserved C-terminal catalytic domains. Collinearity analysis indicated that segmental duplication events played a significant role in the evolution of clade A PP2Cs in Rosaceae. Analysis of the expression of 11 clade A RcPP2Cs showed that approximately 60% of these genes responded to drought, high temperature, and salt stress. Among them, RcPP2C24 exhibited the highest responsiveness to both drought and ABA. Furthermore, overexpression of RcPP2C24 significantly reduced drought tolerance in transgenic tobacco by increasing stomatal aperture after exposure to drought stress. The transient overexpression of RcPP2C24 weakened the dehydration tolerance of rose petal discs, while its silencing increased their dehydration tolerance. In summary, our study identified PP2Cs in six Rosaceae species and highlighted the negative role of RcPP2C24 on rose's drought tolerance by inhibiting stomatal closure. Our findings provide valuable insights into understanding the mechanism behind rose's response to drought.

SOD1 is a synthetic-lethal target in PPM1D-mutant leukemia cells.

The DNA damage response is critical for maintaining genome integrity and is commonly disrupted in the development of cancer. PPM1D (protein phosphatase Mg2+/Mn2+-dependent 1D) is a master negative regulator of the response; gain-of-function mutations and amplifications of PPM1D are found across several human cancers making it a relevant pharmacological target. Here, we used CRISPR/Cas9 screening to identify synthetic-lethal dependencies of PPM1D, uncovering superoxide dismutase-1 (SOD1) as a potential target for PPM1D-mutant cells. We revealed a dysregulated redox landscape characterized by elevated levels of reactive oxygen species and a compromised response to oxidative stress in PPM1D-mutant cells. Altogether, our results demonstrate a role for SOD1 in the survival of PPM1D-mutant leukemia cells and highlight a new potential therapeutic strategy against PPM1D-mutant cancers.

Rapeseed PP2C37 Interacts with PYR/PYL Abscisic Acid Receptors and Negatively Regulates Drought Tolerance.

Global water deficit is a severe abiotic stress threatening the yielding and quality of crops. Abscisic acid (ABA) is a phytohormone that mediates drought tolerance. Protein kinases and phosphatases function as molecular switches in eukaryotes. Protein phosphatases type 2C (PP2Cs) are a major family that play essential roles in ABA signaling and stress responses. However, the role and underlying mechanism of PP2C in rapeseed (Brassica napus L.) mediating drought response has not been reported yet. Here, we characterized a PP2C family member, BnaPP2C37, and its expression level was highly induced by ABA and dehydration treatments. It negatively regulates drought tolerance in rapeseed. We further identified that BnaPP2C37 interacted with multiple PYR/PYL receptors and a drought regulator BnaCPK5 (calcium-dependent protein kinase 5) through yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays. Specifically, BnaPYL1 and BnaPYL9 repress BnaPP2C37 phosphatase activity. Moreover, the pull-down assay and phosphatase assays show BnaPP2C37 interacts with BnaCPK5 to dephosphorylate BnaCPK5 and its downstream BnaABF3. Furthermore, a dual-luciferase assay revealed BnaPP2C37 transcript level was enhanced by BnaABF3 and BnaABF4, forming a negative feedback regulation to ABA response. In summary, we identified that BnaPP2C37 functions negatively in drought tolerance of rapeseed, and its phosphatase activity is repressed by BnaPYL1/9 whereas its transcriptional level is upregulated by BnaABF3/4.

SlPP2C2 interacts with FZY/SAUR and regulates tomato development via signaling crosstalk of ABA and auxin.

Abscisic acid (ABA) signaling interacts frequently with auxin signaling when it regulates plant development, affecting multiple physiological processes; however, to the best of our knowledge, their interaction during tomato development has not yet been reported. Here, we found that type 2C protein phosphatase (SlPP2C2) interacts with both flavin monooxygenase FZY, an indole-3-acetic acid (IAA) biosynthetic enzyme, and small auxin upregulated RNA (SAUR) of an IAA signaling protein and regulates their activity, thereby affecting the expression of IAA-responsive genes. The expression level of SlPP2C2 was increased by exogenous ABA, IAA, NaCl, or dehydration treatment of fruits, leaves, and seeds, and it decreased in imbibed seeds. Manipulating SlPP2C2 with overexpression, RNA interference, and CRISPR/Cas9-mediated genome editing resulted in pleiotropic changes, such as morphological changes in leaves, stem trichomes, floral organs and fruits, accompanied by alterations in IAA and ABA levels. Furthermore, the RNA-seq analysis indicated that SlPP2C2 regulates the expression of auxin-/IAA-responsive genes in different tissues of tomato. The results demonstrate that SlPP2C2-mediated ABA signaling regulates the development of both vegetative and reproductive organs via interaction with FZY/SAUR, which integrates the cross-talk of ABA and auxin signals during development and affects the expressions of development-related genes in tomato.

miR-743b-3p promotes hepatic lipogenesis via branched-chain amino acids (BCAA) metabolism by targeting PPM1K in aged mice.

BACKGROUND: Lipid metabolism disorders appear to play an important role in the ageing process, thus understanding the cellular and molecular mechanisms underlying the association of ageing with elevated vulnerability to lipid metabolism related diseases is crucial towards promoting quality of life in old age. MicroRNAs (miRNAs) have emerged as crucial regulators of lipid metabolism, and some miRNAs have key roles in ageing. METHODS: In this study, we investigated changes in liver lipid metabolism of ageing mice and the mechanisms of the altered expression of miRNAs in the ageing liver which contributes to the age-dependent increase in lipid synthesis. Here we found that miR-743b-3p was higher expressed in the liver tissues of ageing mice through the small RNA sequencing and bioinformatics analysis, and its target PPM1K was predicted and confirmed the target relationship of miR-743b-3p with PPM1K in the aged mouse liver tissues and the cultured senescent hepatocytes in vitro. Moreover, using the transfected miR-743b-3p mimics/inhibitors into the senescent hepatocyte AML12. RESULTS: We found that miR-743b-3p inhibition reversed the hepatocyte senescence, and finally decreased the expression of genes involved in lipid synthesis(Chrebp, Fabp4, Acly and Pparγ) through increasing the target gene expression of PPM1K which regulated the expression of branched-chain amino acids (BCAA) metabolism-related genes (Bckdhα, Bckdk, Bcat2, Dbt). CONCLUSIONS: These results identify that age-induced expression of miR-743b-3p inhibits its target PPM1K which induces BCAA metabolic disorder and regulates hepatocyte lipid accumulation during ageing.