Raf kinase inhibitor protein combined with phosphorylated extracellular signal-regulated kinase offers valuable prognosis in gastrointestinal stromal tumor

BACKGROUND Gastrointestinal stromal tumors(GISTs)are the most common mesenchymal tumors of the gastrointestinal tract.Tyrosine kinase inhibitors,such as imatinib,have been used as first-line therapy for the treatment of GISTs.Although these drugs have achieved considerable efficacy in some patients,reports of resistance and recurrence have emerged.Extracellular signal-regulated kinase 1/2(ERK1/2)protein,as a member of the mitogen-activated protein kinase(MAPK)family,is a core molecule of this signaling pathway.Nowadays,research reports on the important clinical and prognostic value of phosphorylated-ERK(P-ERK)and phosphorylated-MAPK/ERK kinase(P-MEK)proteins closely related to raf kinase inhibitor protein(RKIP)have gradually emerged in digestive tract tumors such as gastric cancer,colon cancer,and pancreatic cancer.However,literature on the expression of these downstream proteins combined with RKIP in GIST is scarce.This study will focus on this aspect and search for answers to the problem.AIM To detect the expression of RKIP,P-ERK,and P-MEK protein in GIST and to analyze their relationship with clinicopathological characteristics and prognosis of this disease.Try to establish a new prognosis evaluation model using RKIP and PERK in combination with analysis and its prognosis evaluation efficacy.METHODS The research object of our experiment was 66 pathologically diagnosed GIST patients with complete clinical and follow-up information.These patients received surgical treatment at China Medical University Affiliated Hospital from January 2015 to January 2020.Immunohistochemical method was used to detect the expression of RKIP,PERK,and P-MEK proteins in GIST tissue samples from these patients.Kaplan-Meier method was used to calculate the survival rate of 63 patients with complete follow-up data.A Nomogram was used to represent the new prognostic evaluation model.The Cox multivariate regression analysis was conducted separately for each set of risk evaluation factors,based on two risk classification systems[the new risk grade model vs the modified National Institutes of Health(NIH)2008 risk classification system].Receiver operating characteristic(ROC)curves were used for evaluating the accuracy and efficiency of the two prognostic evaluation systems.RESULTS In GIST tissues,RKIP protein showed positive expression in the cytoplasm and cell membrane,appearing as brownish-yellow or brown granules.The expression of RKIP was related to GIST tumor size,NIH grade,and mucosal invasion.P-ERK protein exhibited heterogeneous distribution in GIST cells,mainly in the cytoplasm,with occasional presence in the nucleus,and appeared as brownish-yellow granules,and the expression of P-ERK protein was associated with GIST tumor size,mitotic count,mucosal invasion,and NIH grade.Meanwhile,RKIP protein expression was negatively correlated with P-ERK expression.The results in COX multivariate regression analysis showed that RKIP protein expression was not an independent risk factor for tumor prognosis.However,RKIP combined with P-ERK protein expression were identified as independent risk factors for prognosis with statistical significance.Furthermore,we establish a new prognosis evaluation model using RKIP and P-ERK in combination and obtained the nomogram of the new prognosis evaluation model.ROC curve analysis also showed that the new evaluation model had better prognostic performance than the modified NIH 2008 risk classification system.CONCLUSION Our experimental results showed that the expression of RKIP and P-ERK proteins in GIST was associated with tumor size,NIH 2008 staging,and tumor invasion,and P-ERK expression was also related to mitotic count.The expression of the two proteins had a certain negative correlation.The combined expression of RKIP and P-ERK proteins can serve as an independent risk factor for predicting the prognosis of GIST patients.The new risk assessment model incorporating RKIP and P-ERK has superior evaluation efficacy and is worth further practical application to validate.

Death-associated protein kinase 1 is associated with cognitive dysfunction in major depressive disorder

We previously showed that death-associated protein kinase 1(DAPK1)expression is increased in hippocampal tissue in a mouse model of major depressive disorde and is related to cognitive dysfunction in Alzheimer's disease.In addition,depression is a risk factor for developing Alzheimer's disease,as well as an early clinical manifestation of Alzheimer's disease.Meanwhile,cognitive dysfunction is a distinctive feature of major depressive disorder.Therefore,DAPK1 may be related to cognitive dysfunction in major depressive disorder.In this study,we established a mouse model of major depressive disorder by housing mice individually and exposing them to chronic,mild,unpredictable stressors.We found that DAPK1 and tau protein levels were increased in the hippocampal CA3 area,and tau was hyperphosphorylated at Thr231,Ser262,and Ser396 in these mice.Furthermore,DAPK1 shifted from axonal expression to overexpression on the cell membrane.Exercise and treatment with the antidepressant drug citalopram decreased DAPK1 expression and tau protein phosphorylation in hippocampal tissue and improved both depressive symptoms and cognitive dysfunction.These results indicate that DAPK1 may be a potential reason and therapeutic target of cognitive dysfunction in major depressive disorder.

Interleukin-1 beta up-regulates tissue inhibitor of matrix metalloproteinase-1 mRNA and phosphorylation of c-jun N-terminal kinase and p38 in hepatic stellate cells

AIM： To study the relationship between interleukin-lbeta （IL-1β） up-regulating tissue inhibitor of matrix metalloproteinase-1 （TIMMP-1） mRNA expression and phosphorylation of both c-jun N-terminal kinase （INK） and p38 in rat heffatic stellate cells （HSC）. METHODS： RT-PCR was performed to measure the expression of TIMMP-1 mRNA in rat HSC. Western blot was performed to measure IL-1β-induced JNK and p38 activities in rat HSC. RESULTS： TIMMP-1 mRNA expression （1.191± 0.079） was much higher after treatment with IL-1β （10 ng/mL） for 24 h than in control group （0.545±0.091） （P〈0.01）. IL-1β activated INK and p38 in a time-dependent manner. After stimulation with IL-1β for 0, 5, 15, 30, 60 and 120 min, the INK activity was 0.982±0.299, 1.501±0.720, 2.133±0.882, 3.360±0.452, 2.181±0.789, and 1.385 ± 0.368, respectively. There was a significant difference in JNK activity at 15 min （P〈 0.01）, 30 min （P〈 0.01） and 60 min （P〈0.01） in comparison to that at 0 min. The p38 activity was 1.061±0.310, 2.050±0.863, 2.380±0.573, 2.973±0.953, 2.421±0.793, and 1.755 ± 0.433 at the 6 time points （0, 5, 15, 30, 60 and 120 min） respectively. There was a significant difference in p38 activity at 5 min （P〈0.05）, 15 min （P〈0.01）, 30 min （P〈0.01） and 60 min （P〈0.01） compared to that at 0 min. TIMMP-1 mRNA expression trended to decrease in 3 groups pretreated with different concentrations of SP600125 （10 μmol/L, 1.022±0.113; 20 μmol/L, 0.869±0.070; 40 μmol/L, 0.666±0.123）. Their decreases were all significant （P〈0.05, P〈0.01, P〈0.01） in comparison to control group （without SP600125 treatment, 1.163±0.107）. In the other 3 groups pretreated with different concentrations of SB203580 （10 μmol/L, 1.507±0.099; 20 μmol/L, 1.698±0.107; 40 μmol/L, 1.857±0.054）, the expression of TIMMP-1 mRNA increased. Their levels were higher than those in the control group （without SB203580 treatment, 1.027 ± 0.061） with a significant statistical significance （P〈 0.01）. CONCLUSION： IL-1β has a direct action on hepatic fibrosis by up-regulating TIMMP-1 mRNA expression in ratessionin in rate HSC.JNK and p38 mitogen-activated protein kinases （MAPKs） are involved in IL-1β-induced TIMMP-1 gene expression, and play a distinct role in this process, indicating that p38 and .INK pathways cooperatively mediate TIMP-1 mRNA expression in rat HSC.

PTEN-induced kinase 1-induced dynamin-related protein 1 Ser637 phosphorylation reduces mitochondrial fission and protects against intestinal ischemia reperfusion injury

BACKGROUND Intestinal ischemia reperfusion(I/R)occurs in various diseases,such as trauma and intestinal transplantation.Excessive reactive oxygen species(ROS)accumulation and subsequent apoptotic cell death in intestinal epithelia are important causes of I/R injury.PTEN-induced putative kinase 1(PINK1)and phosphorylation of dynamin-related protein 1(DRP1)are critical regulators of ROS and apoptosis.However,the correlation of PINK1 and DRP1 and their function in intestinal I/R injury have not been investigated.Thus,examining the PINK1/DRP1 pathway may help to identify a protective strategy and improve the patient prognosis.AIM To clarify the mechanism of the PINK1/DRP1 pathway in intestinal I/R injury.METHODS Male C57BL/6 mice were used to generate an intestinal I/R model via superior mesenteric artery occlusion followed by reperfusion.Chiu’s score was used to evaluate intestinal mucosa damage.The mitochondrial fission inhibitor mdivi-1 was administered by intraperitoneal injection.Caco-2 cells were incubated in vitro in hypoxia/reoxygenation conditions.Small interfering RNAs and overexpression plasmids were transfected to regulate PINK1 expression.The protein expression levels of PINK1,DRP1,p-DRP1 and cleaved caspase 3 were measured by Western blotting.Cell viability was evaluated using a Cell Counting Kit-8 assay and cell apoptosis was analyzed by TUNEL staining.Mitochondrial fission and ROS were tested by MitoTracker and MitoSOX respectively.RESULTS Intestinal I/R and Caco-2 cell hypoxia/reoxygenation decreased the expression of PINK1 and p-DRP1 Ser637.Pretreatment with mdivi-1 inhibited mitochondrial fission,ROS generation,and apoptosis and ameliorated cell injury in intestinal I/R.Upon PINK1 knockdown or overexpression in vitro,we found that p-DRP1 Ser637 expression and DRP1 recruitment to the mitochondria were associated with PINK1.Furthermore,we verified the physical combination of PINK1 and p-DRP1 Ser637.CONCLUSION PINK1 is correlated with mitochondrial fission and apoptosis by regulating DRP1 phosphorylation in intestinal I/R.These results suggest that the PINK1/DRP1 pathway is involved in intestinal I/R injury,and provide a new approach for prevention and treatment.

Existence and Characteristics of Tonoplast-bound Protein Kinase in the Tip Cell of Maize Root

For understanding the function of tonoplast protein in plant cell signal pathway, we have identified an integral protein kinase activity from the highly purified tonoplast isolated from maize ( Zea mays L.) root by a new nonradioactive method in which a color labeled peptide was used as substrate. The protein kinase was Ca 2+ _dependent and CaM and phosphatidylserine_independent, like the calmodulin_like domain protein kinase (CDPK) in many plants. The optimal pH value and Ca 2+ concentration were 6.5 and 10 μmol/L, respectively. According to the optimal pH value and the effect of detergent, it could be inferred that the active site of this protein kinase is oriented toward the cytoplasm. Zn 2+ had no obvious effect on its activity, indicating that this protein kinase has no zinc_finger domain that exists in some mammalian protein kinases. At the same time, when tonoplast proteins were prephosphorylated in the presence of Ca 2+ and ATP, both the ATP_hydrolysis and the proton_transport activity of vacuolar H +_ATPase were stimulated. This stimulation could be reversed by an alkaline_phosphatase. These results indicate that a Ca 2+ _dependent protein kinase was located in the tonoplast, and a Ca 2+ _dependent phosphorylation, probably caused by this kinase, activated the vacuolar H +_ATPase activity. These results are helpful for further research on the function of CDPK in the course of signal transduction in plants.

Electroacupuncture reduces apoptotic index and inhibits p38 mitogen-activated protein kinase signaling pathway in the hippocampus of rats with cerebral ischemia/reperfusion injury

Electroacupuncture attenuates cerebral hypoxia and neuronal apoptosis induced by cerebral ischemia/reperfusion injury.To further identify the involved mechanisms,we assumed that electroacupuncture used to treat cerebral ischemia/reperfusion injury was associated with the p38 mitogen-activated protein kinase（MAPK） signaling pathway.We established rat models of cerebral ischemia/reperfusion injury using the modified Zea-Longa＇s method.At 30 minutes before model establishment,p38 MAPK blocker SB20358 was injected into the left lateral ventricles.At 1.5 hours after model establishment,electroacupuncture was administered at acupoints of Chize（LU5）,Hegu（LI4）,Zusanli（ST36）,and Sanyinjiao（SP6） for 20 minutes in the affected side.Results showed that the combination of EA and SB20358 injection significantly decreased neurologic impairment scores,but no significant differences were determined among different interventional groups.Hematoxylin-eosin staining also showed reduced brain tissue injuries.Compared with the SB20358 group,the cells were regularly arranged,the structures were complete,and the number of viable neurons was higher in the SB20358 ＋ electroacupuncture group.Terminal deoxynucleotidyl transferase（Td T）-mediated d UTP nick-end labeling assay showed a decreased apoptotic index in each group,with a significant decrease in the SB20358 ＋ electroacupuncture group.Immunohistochemistry revealed reduced phosphorylated p38 expression at 3 days in the electroacupuncture group and SB20358 ＋ electroacupuncture group compared with the ischemia/reperfusion group.There was no significant difference in phosphorylated p38 expression between the ischemia/reperfusion group and SB20358 group.These findings confirmed that the electroacupuncture effects on mitigating cerebral ischemia/reperfusion injury are possibly associated with the p38 MAPK signaling pathway.A time period of 3 days could promote the repair of ischemic cerebral nerves.

Cellular localization and biochemical characterization of a novel calciumdependent protein kinase from tobacco

By screening tobacco cDNA library with MCK1 as a probe, we isolated a cDNA clone NtCPK5 （accession number AY971376）, which encodes a typical calcium-dependent protein kinase. Sequence analyses indicated that NtCPK5 is related to both CPKs and CRKs superfamilies and has all of the three conserved domains of CPKs. The biochemical activity of NtCPK5 was calcium-dependent. NtCPK5 had Vmax and Km of 526nmol/min/mg and 210μg/ml respectively with calf thymus histone （fraction Ⅲ, abbreviated to histone Ⅲs） as substrate. For substrate syntide-2, NtCPK5 showed a higher Vmax of 2008 nmol/min/mg and a lower Km of 30μM. The K0.5 of calcium activation was 0.04μM or 0.06μM for histone Ⅲs or syntide-2 respectively. The putative myristoylation and palmitoylation consensus sequence of NtCPK5 suggests that it could be a membrane-anchoring protein. Indeed, our transient expression experiments with wild type and mutant forms of NtCPK5/GFP fusion proteins showed that NtCPK5 was localized to the plasma membrane of onion epidermal cells and that the localization required the N-terminal acylation sites of NtCPK5/GFP. Taking together, our data have demonstrated the biochemical characteristics of a novel protein NtCPK5 and its subcellular localization as a membrane-anchoring protein.

Hippocampal activation of c-Jun N-terminal kinase,protein kinase B,and p38 mitogen-activated protein kinase in a chronic stress rat model of depression

Recent studies have shown that varied stress stimuli activate c-Jun N-terminal kinase （JNK）, protein kinase B （Akt）, and p38 mitogen-activated protein kinase （p38） signal transduction pathway, and also regulate various apoptotic cascades. JNK and p38 promote apoptosis, but Akt protects against apoptosis, in hippocampal neurons. However, changes in the transduction pathway in different regions of brain tissues in a chronic stress rat model of depression remain poorly understood. Results from this study showed that JNK phosphorylation levels were significantly greater in the stress group hippocampus compared with the control group （P 〈 0.05）. No significant difference in JNK phosphorylation levels was detected in the rat cerebral cortex between stress and control groups, and no significant difference in Akt and p38 phosphorylation levels was detected in the rat hippocampus and cerebral cortex between stress and control groups （P 〉 0.05）. These results suggested that the JNK signal pathway is activated by JNK phosphorylation and participates in pathophysiological changes in rat models of depression.

THE LA ANTIGEN INHIBITS THE ACTIVATION OF THE INTERFERON-INDUCIBLE PROTEIN KINASEPKR BY SEQUESTERING AND UNWINDING DOUBLE-STRANDED RNA

The La (SS-B) autoimmune antigen is an RNA-binding protein that is present in both nucleus and cytoplasm of eukaryotic cells.The spectrum of RNAs that interact with the antigen includes species which also bind to the interferon-inducible protein kinase PKR.We have investigated whether the La antigen can regulate the activity of PKR and have observed that both the autophosphorylation of the protein kinase that accompanies its activation by dsRNA and the dsRNA-dependent phosphorylation of the subunit of polypeptide chain initiation factor eIF-2 by PKR are inhibited in the presence of recombinant La antigen. This inhibition is partially relieved at higher concentrations of dsRNA.Once activated by dsRNA the protein kinase activity of PKR is insensitive to the La antigen. We have demonstrated by a filter binding assay that La is a dsRNA binding protein.Furthermore, when recombinant La is incubated with a 900bp synthetic dsRNA or with naturally occurring reovirus dsRNA it converts these substrates to single-stranded forms.We conclude that the La antigen inhibits the dsRNA-dependent activation of PKR by binding and unwinding dsRNA and that it may therefore play a role in the regulation of this protein kinase in interferon-treated or virus-infected cells.

Functional repertoire of protein kinases and phosphatases in synaptic plasticity and associated neurological disorders

Protein phosphorylation and dephosphorylation are two essential and vital cellular mechanisms that regulate many receptors and enzymes through kinases and phosphatases.Ca^2+- dependent kinases and phosphatases are responsible for controlling neuronal processing;balance is achieved through opposition.During molecular mechanisms of learning and memory,kinases generally modulate positively while phosphatases modulate negatively.This review outlines some of the critical physiological and structural aspects of kinases and phosphatases involved in maintaining postsynaptic structural plasticity.It also explores the link between neuronal disorders and the deregulation of phosphatases and kinases.

Protein kinase CK2 in the ER stress response

The endoplasmic reticulum is the central organelle within a eukaryotic cell where newly synthesized proteins are processed and properly folded. An excess of unfolded or mis-folded proteins induces ER stress signalling pathways. Usually this means a pro-survival strategy for the cell, whereas under extended stress conditions the ER stress signalling pathways have a pro-apoptotic function. CK2 plays a key role in the regulation of the pro-survival as well as the proapoptotic ER stress signalling by directly modulating the activities of members of the ER stress signalling pathways by phosphorylation, regulating the expression of the key factors of the signalling pathways or binding to regulator proteins. The present review will summarize the state of the art in this new emerging field.

Physiological roles of mitogen-activated-protein-kinase-activated p38-regulated/activated protein kinase

Mitogen-activated protein kinases(MAPKs)are a family of proteins that constitute signaling pathways involved in processes that control gene expression,cell division, cell survival,apoptosis,metabolism,differentiation and motility.The MAPK pathways can be divided into conventional and atypical MAPK pathways.The first group converts a signal into a cellular response through a relay of three consecutive phosphorylation events exerted by MAPK kinase kinases,MAPK kinase,and MAPK.Atypical MAPK pathways are not organized into this three-tiered cascade.MAPK that belongs to both conventional and atypical MAPK pathways can phosphorylate both non-protein kinase substrates and other protein kinases.The latter are referred to as MAPK-activated protein kinases.This review focuses on one such MAPK-activated protein kinase,MAPK-activated protein kinase 5(MK5)or p38-regulated/activated protein kinase(PRAK).This protein is highly conserved throughout the animal kingdom and seems to be the target of both conventional and atypical MAPK pathways.Recent findings on the regulation of the activity and subcellular localization,bona fide interaction partners and physiological roles of MK5/PRAK are discussed.

Evidence, hypotheses and significance of MAP kinase TNNI3K interacting with its partners

TNNI3K is a cardiac-specific and cardiac troponin I(cT n I)-interacting MAP kinase, known to play important roles in promoting cardiac differentiation, maintenance of beating rhythm and contractual force. The molecular structure of TNNI3 K contains three kinds of domain: a seven or ten NH2-terminal ankyrin repeat domain followed by a protein kinase domain and a COOH-terminal serine-rich domain. There are many binding sites in the structure of TNNI3 K for binding to ATP, magnesium, nucleotide, protein kinase C, antioxidant protein 1(AOP-1) and cT n I, indicating TNNI3 K has many interacting partners. This review summarizes the evidence, hypothesis and significance of TNNI3 K interacting with TNNI3 and its other putative interaction partners. From the literature, the interaction partners of TNNI3 K are divided into 2 types following their phenotypic pattern of functions, positive interaction(to increase the cardiac performance) or negative interaction(to suppress the cardiac performance). Following their binding sites, it also can be divided into other 2 types: binding to C-terminal domain(e.g., cT n I) or binding to both ankyrin repeat domain and C-terminal domains(AOP-1).To date, a well understood partner of TNNI3 K is cT nI, from the molecular structure, physiological function, mechanisms and its significance in some physiological and pathophysiological conditions. There are many reasons to believe that, with more understanding on the TNNI3 K interacting with its partners, we can understand more roles of TNNI3 K in some cardiac diseases.

Regulation of Ikaros function by casein kinase 2 and protein phosphatase 1

The Ikaros gene encodes a zinc finger,DNA-binding protein that regulates gene transcription and chromatin remodeling.Ikaros is a master regulator of hematopoiesis and an established tumor suppressor.Moderate alteration of Ikaros activity (e.g.haploinsufficiency) appears to be sufficient to promote malignant transformation in human hematopoietic cells.This raises questions about the mechanisms that normally regulate Ikaros function and the potential of these mechanisms to contribute to the development of leukemia.The focus of this review is the regulation of Ikaros function by phosphorylation/dephosphorylation.Site-specific phosphorylation of Ikaros by casein kinase 2 (CK2) controls Ikaros DNA-binding ability and subcellular localization.As a consequence,the ability of Ikaros to regulate cell cycle progression,chromatin remodeling,target gene expression,and thymocyte differentiation are controlled by CK2.In addition,hyperphosphorylation of Ikaros by CK2 leads to decreased Ikaros levels due to ubiquitinmediated degradation.Dephosphorylation of Ikaros by protein phosphatase 1 (PP1) acts in opposition to CK2 to increase Ikaros stability and restore Ikaros DNA binding ability and pericentromeric localization.Thus,the CK2 and PP1 pathways act in concert to regulate Ikaros activity in hematopoiesis and as a tumor suppressor.This highlights the importance of these signal transduction pathways as potential mediators of leukemogenesis via their role in regulating the activities of Ikaros.

A Highly Sensitive Detection Method, Phos-tag^TMAffinity SDS-PAGE, Used to Analyze a Possible Substrate of CDPK-Related Protein Kinase5 in <i>Arabidopsis</i>

Phosphorylation of proteins is an important post-translational modification. Methods to determine the phosphorylation state of proteins are very important to evaluate diverse biological processes. CRK5 is the CDPK-related protein kinase in Arabidopsis, WD-repeat protein (WDRP) might be CRK5-interact-protein based on Y2H results. Here, we used bimolecular fluorescence complementation (BiFC) further to study and visualize the interaction between CRK5 and WDRP in living cells. Then, we combined Phos-tagTM SDS-PAGE with western blot (WB) analysis, using WDRP antibody and the anti-6×His antibody, to detect phosphorylated WDRP. This approach confirmed that WDRP might be phosphorylated by CRK5 in vitro. Site mutation analysis suggested that serine-70 might be the amino acid phosphorylated by CRK5 in WDRP. Cell extracts isolated from WT, OERK5, and crk5 used to analyze the kinase reaction using recombinant WDRP as substrate. These results demonstrated that WDRP was phosphorylated by cell extracts and that there may be additional kinases that phosphorylate WDRP in Arabidopsis. Phos-tagTM SDS-PAGE thus provides a suitable and convenient method for analysis of phosphorylation in plants.

Mnk kinase pathway: Cellular functions and biological outcomes

The mitogen-activated protein kinase(MAPK) interacting protein kinases 1 and 2(Mnk1 and Mnk2) play important roles in controlling signals involved in mRNA translation. In addition to the MAPKs(p38 or Erk), multiple studies suggest that the Mnk kinases can be regulated by other known kinases such as Pak2 and/or other unidentified kinases by phosphorylation of residues distinct from the sites phosphorylated by the MAPKs. Several studies have established multiple Mnk protein targets, including PSF, heterogenous nuclear ribonucleoprotein A1, Sprouty 2 and have lead to the identification of distinct biological functions and substrate specificity for the Mnk kinases. In this review we discuss the pathways regulating the Mnk kinases, their known substrates as well as the functional consequences of engagement of pathways controlled by Mnk kinases. These kinases play an important role in mRNA translation via their regulation of eukaryotic initiation factor 4E(eIF4E) and their functions have important implications in tumor biology as well as the regulation of drug resistance to anti-oncogenic therapies. Other studies have identified a role for the Mnk kinases in cap-independent mRNA translation, suggesting that the Mnk kinases can exert important functional effects independently of the phosphorylation of eIF4 E. The role of Mnk kinases in inflammation and inflammationinduced malignancies is also discussed.

A novel secreted protein, NISP1, is phosphorylated by soybean Nodulation Receptor Kinase to promote nodule symbiosis

Nodulation Receptor Kinase(NORK) functions as a co-receptor of Nod factor receptors to mediate rhizobial symbiosis in legumes, but its direct phosphorylation substrates that positively mediate root nodulation remain to be fully identified.Here, we identified a GmNORK-Interacting Small Protein(GmNISP1) that functions as a phosphorylation target of GmNORK to promote soybean nodulation. GmNORKα directly interacted with and phosphorylated GmNISP1. Transcription of GmNISP1 was strongly induced after rhizobial infection in soybean roots and nodules. GmNISP1 encodes a peptide containing 90 amino acids with a “DY” consensus motif at its N-terminus.GmNISP1 protein was detected to be present in the apoplastic space. Phosphorylation of GmNISP1 by GmNORKα could enhance its secretion into the apoplast. Pretreatment with either purified GmNISP1 or phosphorylation-mimic GmNISP1~(12D) on the roots could significantly increase nodule numbers compared with the treatment with phosphorylation-inactive GmNISP1~(12A).The data suggested a model that soybean GmNORK phosphorylates GmNISP1 to promote its secretion into the apoplast, which might function as a potential peptide hormone to promote root nodulation.

Phosphorylation of OsRbohB by the protein kinase OsDMI3 promotes H_(2)O_(2) production to potentiate ABA responses in rice

In rice, the Ca^(2+)/calmodulin-dependent protein kinase OsDMI3 is an important positive regulator of abscisic acid (ABA) signaling. In ABA signaling, H_(2)O_(2) is required for ABA-induced activation of OsDMI3, which in turn increase H_(2)O_(2) production. However, how OsDMI3 regulates H_(2)O_(2) production in ABA signaling remains unknown. Here we show that OsRbohB is the main NADPH oxidase involved in ABA-induced H_(2)O_(2) production and ABA-mediated physiological responses. OsDMI3 directly interacts with and phosphorylates OsRbohB at Ser-191, which is OsDMI3-mediated site-specific phosphorylation in ABA signaling. Further analyses revealed that OsDMI3-mediated OsRbohB Ser-191 phosphorylation positively regulates the activity of NADPH oxidase and the production of H_(2)O_(2) in ABA signaling, thereby enhancing the sensitivity of seed germination and root growth to ABA and plant tolerance to water stress and oxidative stress. Moreover, we discovered that the OsDMI3-mediated OsRbohB phosphorylation and H_(2)O_(2) production is dependent on the sucrose non-fermenting 1-related protein kinases SAPK8/9/10, which phosphorylate OsRbohB at Ser-140 in ABA signaling. Taken together, these results not only reveal an important regulatory mechanism that directly activates Rboh for ABA-induced H_(2)O_(2) production but also uncover the importance of this regulatory mechanism in ABA signaling.

复方芩柏汤调控ERK/JNK信号通路治疗溃疡性结肠炎的效应及机制研究

目的 研究复方芩柏汤对细胞外信号调节激酶(extracellular regulated protein kinases, ERK)/c-Jun氨基末端激酶(cJun N-terminal kinase, JNK)信号通路的调控作用,以及对溃疡性结肠炎(ulcerative colitis, UC)小鼠血清中炎症因子的影响。方法 将60只SPF级健康雄性BALB/C小鼠利用3%葡聚糖硫酸(dextran sulfate sodium, DSS)建立UC模型,造模成功后随机分为模型组(以生理盐水灌肠)、美沙拉嗪组(以0.196 g/kg美沙拉嗪药液灌肠)、复方芩柏汤组(以1.092 g/kg复方芩柏颗粒剂药液灌肠),每组20只,每天保留灌肠2次,连续3周。另取20只正常饲养小鼠作为空白组。在治疗前和治疗后第7、14、21天,观察小鼠体质量、大便性状、便血情况,并计算疾病活动指数(disease activity index, DAI),且于给药结束后进行麻醉取血并取结肠组织。采用HE染色观察各组小鼠结肠组织病理变化情况;ELISA法检测各组小鼠血清中炎症因子白细胞介素(interleukin)-22、IL-6、IL-10、肿瘤坏死因子-α(tumor necrosis factor-α, TNF-α)含量变化情况;采用Western blot法检测各组小鼠结肠组织中的p90核糖体蛋白S6激酶(p90 ribosomal protein S6 kinase, p90RSK)、JNK、磷酸化c-Jun氨基末端激酶(phosphorylated c-Jun N-terminal kinase, p-JNK)、细胞外调节蛋白激酶1/2(extracellular regulated protein kinases 1/2, ERK 1/2)、磷酸化细胞外调节蛋白激酶1/2(phospho extracellular regulated protein kinases, p-ERK 1/2)蛋白的表达。结果 在治疗的第7、14、21天,美沙拉嗪组、复方芩柏汤组小鼠体质量均明显高于模型组(P<0.05,P<0.01),DAI评分明显低于模型组(P<0.05,P<0.01)。光镜下,与模型组相比,美沙拉嗪组及复方芩柏汤组小鼠结肠组织病理改变呈不同程度的恢复,炎症浸润减轻。给药结束后,与空白组比较,模型组p90RSK、p-JNK、p-ERK 1/2蛋白以及IL-6、TNF-α蛋白表达明显升高(P<0.01);与模型组比较,美沙拉嗪组和复方芩柏汤组p90RSK、p-JNK、p-ERK 1/2蛋白以及IL-6、TNF-α蛋白表达明显降低(P<0.05,P<0.01),抗炎因子IL-22、IL-10含量明显升高(P<0.01)。结论 复方芩柏汤可能通过抑制ERK/JNK信号通路,促进抗炎因子IL-22、IL-10的表达,抑制促炎因子IL-6、TNF-α的表达,减少肠道炎症反应,促进肠上皮细胞增殖,改善肠黏膜屏障,促进UC小鼠肠道黏膜组织损伤修复。

LATS1 Promotes B-ALL Tumorigenesis by Regulating YAP1 Phosphorylation and Subcellular Localization

Objective YAP1 plays a dual role as an oncogene and tumor suppressor gene in several tumors;differentiating between these roles may depend on the YAP1 phosphorylation pattern.The specific function of YAP1 in B cell acute lymphoblastic leukemia(B-ALL),however,is currently unclear.Thus,in the present study,the role of YAP1 in B-ALL was investigated using relevant cell lines and patient datasets.Methods The effects of shRNA-mediated knockdown on YAP1 and LATS1 levels in the NALM6 and MOLT-4 cell lines were examined using Western blotting,quantitative real-time polymerase chain reaction,flow cytometry,immunostaining,and nude mouse subcutaneous tumorigenesis experiments.Gene expression levels of Hippo pathway-related molecules before and after verteporfin(VP)treatment were compared using RNA-Seq to identify significant Hippo pathway-related genes in NALM6 cells.Results Patients with ALL showing high YAP1 expression and low YAP1-Ser127 phosphorylation levels had worse prognoses than those with low YAP1 protein expression and high YAP1-Ser127 phosphorylation levels.YAP1-Ser127 phosphorylation levels were lower in NALM6 cells than in MOLT-4 and control cells;YAP1 was distributed in the nuclei in NALM6 cells.Knockdown of YAP1 inhibited MOLT-4 and NALM6 cell proliferation and arrested the NALM6 cell cycle in the G0/G1 phase.Before and after VP treatment,the expression of the upstream gene LATS1 was upregulated;its overexpression promoted YAP1-Ser127 phosphorylation.Further,YAP1 was distributed in the plasma.Conclusion LATS1 may downregulate YAP1-Ser127 phosphorylation and maintain B-ALL cell function;thus,VP,which targets this axis,may serve as a new therapeutic method for improving the outcomes for B-ALL patients.