Rap1 is a small G protein belonging to the RAS superfamily. Rap1 signalling has effects on cell growth, cell proliferation and involves in regulation of the mitogen activated protein (MAP) kinase or ERK (extracellular signal regulated kinase) cascade. Rap1 will directly activate ERK through B-Raf. B-Raf is a member of Raf family, and presents in neuronal and hematopoietic cells. Oncogenic mutations of gene RAS are most frequent and detected in 20% - 30% of human leukemias and 10% - 15% of MDS cases. The review summarizes the regulatory function of Rap1 in development of hematopoietic cells and effect of Rap1 in hematologic malignancies.
Hematologic Neoplasms ; genetics ; metabolism ; Humans ; Signal Transduction ; rap1 GTP-Binding Proteins ; genetics ; metabolism

BACKGROUNDMelanoma has the highest mortality among all superficial malignant tumors. The poor prognosis is due to its high metastasis rate and the lack of therapeutic targets. As a molecular switch that controls tumor metastasis, Ras homology C (RhoC) has been correlated with tumor progression, especially tumor invasion and metastasis. However, little research has been done about the effects of RNA interference (RNAi) targeting RhoC on the invasion and metastasis of melanoma. In this study, we constructed an RNAi lentivirus vector targeting the RhoC gene of melanoma cells and identified its silencing effects on the RhoC gene.

METHODSBased on the RhoC gene encoding information, three pGPU6/GFP/Neo-short hairpin (shRNA) plasmids were constructed. After detecting their silencing effects on the RhoC gene of A375 cells, the most effective pGPU6/GFP/Neo-shRNA plasmid was packed with lentivirus to construct the recombinant pLenti6.3-EGFP-453 targeting RhoC. The lentivirus vector was used to infect A375 cells, and then the expression of RhoC mRNA and protein were determined with real-time PCR and Western blotting.

RESULTSThe plasmids pGPU6/GFP/Neo-shRNA 336, pGPU6/GFP/Neo-shRNA 453, and pGPU6/GFP/Neo-shRNA 680 were constructed. After they were transfected into A375 cells, the expressions of RhoC mRNA and protein were 1.47 ± 0.26, 1.13 ± 0.16, 1.39 ± 0.11 and 70.98 ± 9.21, 50.67 ± 6.06, 65.77 ± 4.06, respectively. pGPU6/GFP/Neo-shRNA 453 was the most effective sequence, and was used to successfully construct the pLenti6.3-EGFP-453 lentiviral vector targeting RhoC. pLenti6.3-EGFP-453 was used to infect A375 cells. The expression of RhoC mRNA and protein were 1.05 ± 0.05 and 62.04 ± 15.86 in the lentivirus group, 4.21 ± 0.24 and 220.86 ± 24.07 in the negative lentivirus control group, and 4.63 ± 0.32 and 257.39 ± 12.30 in the normal control group respectively with the difference between the lentivirus group and the control groups being statistically significant (P < 0.05).

CONCLUSIONThe successfully constructed pLenti6.3-EGFP-453 vector targeting the RhoC can effectively infect human melanoma A375 cells in vitro, and significantly inhibit the RhoC mRNA and protein expression.

Cell Line, Tumor ; Genetic Vectors ; genetics ; Humans ; Lentivirus ; genetics ; Melanoma ; genetics ; therapy ; RNA Interference ; physiology ; rho GTP-Binding Proteins ; genetics ; metabolism ; rhoC GTP-Binding Protein

Guanylate-binding protein 1 (GBP1) is an interferon induced protein, that belongs to the guany late-binding protein family. GBP1 is widely involved in anti-infection immune responses, anti-tumor activity and various biological reactions. Recent studies have proved that IFN-alpha, IFN-beta, IFN-gamma, IL1alpha, IL1beta, TNF-alpha and LPS can induce GBP1 expression; hence, the diverse biological functions of GBP1 have been gradually deduced and exploited. Many studies have been performed over recent years to understand the exact mechanisms that underlie the anti-infection and anti-tumor properties of GBP1. This review describes the molecular structure, biological activity, anti-infective properties and other functions of GBP1, in order to provide insights into the divergent roles of GBP1 in the regulation of various biological processes.
Animals ; Antineoplastic Agents ; metabolism ; Antiviral Agents ; metabolism ; GTP-Binding Proteins ; chemistry ; genetics ; metabolism ; Humans ; Interferons ; genetics ; metabolism

Hypertension is a clinical syndrome characterized by elevated systemic arterial blood pressure, which may be accompanied by functional or organic damage of heart, brain, kidney and other organs. The pathogenesis and development of hypertension are affected by genetic, environmental, epigenetic, intestinal microbiota and other factors. They are the result of multiple factors that promote the change of blood pressure level and vascular resistance. G protein coupled receptors(GPCRs) are the largest and most diverse superfamily of transmembrane receptors that transmit signals across cell membranes and mediate a large number of cellular responses required by human physiology. A variety of GPCRs are involved in the control of blood pressure and the maintenance of normal function of cardiovascular system. Hypertension contributes to the damages of heart, brain, kidney, intestine and other organs. Many GPCRs are expressed in various organs to regulate blood pressure. Although many GPCRs have been used as therapeutic targets for hypertension, their efficacy has not been fully studied. The purpose of this paper is to elucidate the role of GPCRs in blood pressure regulation and its distribution in target organs. The relationship between GPCRs related to intestinal microorganisms and blood pressure is emphasized. It is proposed that traditional Chinese medicine may be a new way to treat hypertension by regulating the related GPCRs via intestinal microbial metabolites.
Blood Pressure ; GTP-Binding Proteins ; Gastrointestinal Microbiome ; Humans ; Hypertension/genetics* ; Receptors, G-Protein-Coupled/metabolism*

OBJECTIVETo investigate the significance of Rac subfamily members in the gastrointestinal carcinogenesis and progression.

METHODSThe mRNA expression of Rac1, Rac2 and Rac3 in 12 kinds of gastrointestinal cancer cell lines was examined by semi-quantitative RT-PCR. The activities of Rac1 protein in 5 kinds of gastric cancer cell lines were tested by pull-down assay.

RESULTSCompared with the normal gastric mucosa and intestinal epithelial cell line, the mRNA expression of Rac1 and Rac3 was up-regulated in most of gastrointestinal cancer cell lines. The activities of Rac1 protein increased markedly in gastric cancer cell lines.

CONCLUSIONThe increased mRNA expression of Rac1 and Rac3 in gastrointestinal cancer cell lines and the abnormal activation of Rac1 protein in gastric cancer cell lines might be correlated with the carcinogenesis of gastrointestinal cancer.

Cell Line, Tumor ; Gastrointestinal Neoplasms ; metabolism ; Humans ; RNA, Messenger ; analysis ; Reverse Transcriptase Polymerase Chain Reaction ; rac GTP-Binding Proteins ; genetics ; rac1 GTP-Binding Protein ; analysis ; genetics

OBJECTIVETo detect the expression of RhoC protein in human primary hepatocellular carcinoma (HCC) and pericancerous liver (PCL) tissues and its relation to HCC prognosis.

METHODSImmunohistochemical method was used to detect the expression of RhoC protein in HCC, PCL of 43 patients. Thirty-six patients were followed up after they received radical resection.

RESULTThe expression of RhoC protein in HCC was significantly higher than that in PCL. Rhoc expression was increased in cases with poor differentiation, portal vascular invasion, unintact envelope and multiple masses. The survival analysis showed that HCC with lower RhoC protein expression had better clinical outcomes.

CONCLUSIONRhoC protein expression is correlated with infiltration and metastasis in HCC. RhoC protein can be used as a prognostic indicator for HCC.

Adult ; Carcinoma, Hepatocellular ; metabolism ; pathology ; Female ; Humans ; Liver Neoplasms ; metabolism ; pathology ; Male ; Neoplasm Invasiveness ; Neoplasm Metastasis ; Prognosis ; rho GTP-Binding Proteins ; biosynthesis ; genetics ; rhoC GTP-Binding Protein

To study the molecular mechanism of salt stress response of peanut small GTP binding protein gene AhRabG3f, a 1 914 bp promoter fragment upstream of the start codon of AhRabG3f gene (3f-P) from peanut was cloned. Subsequently, five truncated fragments (3f-P1-3f-P5) with lengths of 1 729, 1 379, 666, 510 and 179 bp were obtained through deletion at the 5' end, respectively. Plant expression vectors where these six promoter fragments were fused with the gus gene were constructed and transformed into tobacco by Agrobacterium-mediated method, respectively. GUS expression in transgenic tobacco and activity analysis were conducted. The gus gene expression can be detected in the transgenic tobacco harboring each promoter segment, among which the driving activity of the full-length promoter 3f-P was the weakest, while the driving activity of the promoter segment 3f-P3 was the strongest. Upon exposure of the transgenic tobacco to salt stress, the GUS activity driven by 3f-P, 3f-P1, 3f-P2 and 3f-P3 was 3.3, 1.2, 1.9 and 1.2 times compared to that of the transgenic plants without salt treatment. This suggests that the AhRabG3f promoter was salt-inducible and there might be positive regulatory elements between 3f-P and 3f-P3 in response to salt stress. The results of GUS activity driven by promoter fragments after salt treatment showed that elements included MYB and GT1 between 1 930 bp and 1 745 bp. Moreover, a TC-rich repeat between 682 bp and 526 bp might be positive cis-elements responsible for salt stress, and an MYC element between 1 395 bp and 682 bp might be a negative cis-element responsible for salt stress. This study may facilitate using the induced promoter to regulate the salt resistance of peanut.
Arachis/genetics* ; Fabaceae/genetics* ; GTP-Binding Proteins/metabolism* ; Gene Expression Regulation, Plant ; Glucuronidase/metabolism* ; Plant Proteins/metabolism* ; Plants, Genetically Modified/genetics* ; Salt Stress ; Stress, Physiological/genetics* ; Tobacco/genetics*

OBJECTIVETo investigate the expression of the anti-oncogene ARHI in the endometriotic tissue and explore its clinical significance.

METHODSA semiquantitative analysis of the expression of ARHI mRNA and protein in the ectopic and eutopic endometrium of women with endometriosis was conducted using RT-PCR and Western blotting in comparison with that in the endometrium of women without endometriosis. Immunohistochemistry and in situ hybridization were performed for semi qualitative analysis and localization of ARHI expression.

RESULTSThe expression levels of ARHI mRNA and protein differed significantly between the groups. ARHI was expressed at significantly higher levels in ectopic endometrium than in eutopic and normal endometrium (P<0.005), but showed no significant difference between the latter two tissues (Pgt;0.05). The positivity rate ARHI DNA was 97.3% in the endometrium of women without endometriosis, 100% in the ectopic endometrium and 93.8% in the eutopic endometrium of women with endometriosis. immunohistochemistry showed an ARHI positivity of 93.2% in the endometrium of women without endometriosis, 100% in the ectopic endometrium and 92.3% in the eutopic endometrium of women with endometriosis. The expression patterns of ARHI DNA and protein were consistent. Immunohistochemistry in 5 cases of malignant endometriosis showed negative ARHI expression in 4 cases and weak positivity in 1 case.

CONCLUSIONARHI expressions are present in the endometrium and up-regulated in ectopic endometrium, whereas in the ectopic endometrium of patients with malignant endometriosis its expression is often negative, suggesting a role of ARHI in infertility and tumorigenesis of endometriosis.

Adult ; Endometriosis ; metabolism ; pathology ; Endometrium ; metabolism ; pathology ; Female ; Genes, Tumor Suppressor ; Humans ; RNA, Messenger ; genetics ; rho GTP-Binding Proteins ; metabolism

GPCR proteins represent the largest family of signaling membrane proteins in eukaryotic cells. Their importance to basic cell biology, human diseases, and pharmaceutical interventions is well established. Many crystal structures of GPCR proteins have been reported in both active and inactive conformations. These data indicate that agonist binding alone is not sufficient to trigger the conformational change of GPCRs necessary for binding of downstream G-proteins, yet other essential factors remain elusive. Based on analysis of available GPCR crystal structures, we identified a potential conformational switch around the conserved Asp2.50, which consistently shows distinct conformations between inactive and active states. Combining the structural information with the current literature, we propose an energy-coupling mechanism, in which the interaction between a charge change of the GPCR protein and the membrane potential of the living cell plays a key role for GPCR activation.
Binding Sites ; GTP-Binding Proteins ; chemistry ; genetics ; metabolism ; Humans ; Hydrogen Bonding ; Membrane Potentials ; Models, Molecular ; Protein Conformation ; Receptors, G-Protein-Coupled ; chemistry ; genetics ; metabolism ; Signal Transduction

OBJECTIVETo explore the hematopoietic pathophysiology of myelodysplastic syndrome (MDS) at stem/progenitor cell level by analyzing the gene expression profiles associated with hematopoiesis.

METHODSThe differentially expressed genes which were involved in the hematopoiesis were screened by microarray using CD34(+) cells from MDS patients firstly. RQ-PCR was then applied to validate the screened genes using CD34(+) cells from MDS-RA patients who had normal karyotype. The linkages with hematopoiesis among these validated genes were analyzed.

RESULTSAmong the differentially expressed genes in CD34(+) cells of MDS-RA patients, Rap1GAP was up-regulated significantly (P < 0.01). Cadherins, which can interplay with Rap1, including N-cadherin and E-cadherin, were down-regulated significantly (P < 0.01). β-catenin, a downstream effector of cadherins, was highly expressed in MDS-RA patients (P < 0.01). c-myc binding protein was down-regulated (P < 0.01), and c-myc promoter binding protein was up-regulated (P < 0.01). Rac1, Rac2 and Cdc42, which belong to RhoGTPases family and are associated with the cell morphology and hematopoiesis, were all expressed highly in MDS-RA patients (P < 0.01).

CONCLUSIONThe abnormal expression of cadherin, β-catenin and c-myc associated genes were closely related to the dysplastic hematopoiesis of MDS. The down regulation of cadherin was associated with the positive feedback mechanism between Rap1 and cadherin. The aberrant expression of Rac1, Rac2 and Cdc42 may contribute to the morphological dysplasia of MDS.

Cadherins ; genetics ; metabolism ; Gene Expression ; Gene Expression Profiling ; Genes, myc ; Humans ; Myelodysplastic Syndromes ; genetics ; metabolism ; beta Catenin ; genetics ; rap1 GTP-Binding Proteins ; genetics ; metabolism