The molecular mechanism of how hepatocytes maintain cholesterol homeostasis has become much more transparent with the discovery of sterol regulatory element binding proteins (SREBPs) in recent years. These membrane pr...The molecular mechanism of how hepatocytes maintain cholesterol homeostasis has become much more transparent with the discovery of sterol regulatory element binding proteins (SREBPs) in recent years. These membrane proteins aremembers of the basic helix-loop-helix-leucine zipper (bHLHZip) family of transcription factors. They activate the expression of at least 30 genes involved in the synthesis of cholesterol and lipids. SREBPs are synthesized as precursor proteins in the endoplasmic reticulum (ER), where they form a complex with another protein, SREBP cleavage activating protein (SCAP). The SCAP molecule contains a sterol sensory domain. In the presence of high cellular sterol concentrations SCAP confines SREBP to the ER. With low cellular concentrations, SCAP escorts SREBP to activation in the Golgi. There, SREBP undergoes two proteolytic cleavage steps to release the mature, biologically active transcription factor, nuclear SREBP (nSREBP). nSREBP translocates to the nucleus and binds to sterol response elements (SRE) in the promoter/enhancer regions of target genes. Additional transcription factors are required to activate transcription of these genes. Three different SREBPs are known, SREBPs-1a, -1c and -2. SREBP-1a and -1c are isoforms produced from a single gene by alternate splicing. SREBP-2 is encoded by a different gene and does not display any isoforms. It appears that SREBPs alone, in the sequence described above, can exert complete control over cholesterol synthesis, whereas many additional factors (hormones, cytokines, etc.) are required for complete control of lipid metabolism. Medicinal manipulation of the SREBP/SCAP system is expected to prove highly beneficial in the management of cholesterol-related disease.展开更多
目的探讨结直肠癌(colorectal cancer,CRC)组织ras反应元件结合蛋白1(ras-responsive element binding protein 1,RREB1),ankyrin重复结构域1(ankyrin repeat domain 1,ANKRD1)的表达及与临床病理特征和预后不良的关系。方法选取2013年1...目的探讨结直肠癌(colorectal cancer,CRC)组织ras反应元件结合蛋白1(ras-responsive element binding protein 1,RREB1),ankyrin重复结构域1(ankyrin repeat domain 1,ANKRD1)的表达及与临床病理特征和预后不良的关系。方法选取2013年1月~2016年12月复旦大学附属中山医院厦门医院收治的105例CRC患者,应用免疫组织化学SP法检测CRC患者癌组织和癌旁组织RREB1和ANKRD1蛋白表达,分析RREB1和ANKRD1蛋白表达与患者临床病理特征的关系,患者均随访5年,比较不同RREB1和ANKRD1表达患者的预后情况,并分析CRC患者预后不良的影响因素。采用Spearman相关系数分析RREB1与ANKRD1表达的相关性。结果CRC癌组织RREB1蛋白阳性率(59.05%)显著高于癌旁组织(27.61%),差异有统计学意义(χ^(2)=21.120,P=0.000)。CRC癌组织ANKRD1蛋白阳性率(31.43%)显著低于癌旁组织(60.95%),差异有统计学意义(χ^(2)=18.410,P=0.000)。TNM分期Ⅲ期、淋巴结转移N1~N2患者RREB1蛋白阳性率高于TNM分期Ⅰ~Ⅱ期、淋巴结转移N0患者,差异有统计学意义(χ^(2)=4.263,8.199,均P<0.05)。TNM分期Ⅲ期、淋巴结转移N1~N2患者ANKRD1蛋白阳性率低于TNM分期Ⅰ~Ⅱ期、淋巴结转移N0患者,差异有统计学意义(χ^(2)=5.515,7.411,均P<0.05)。RREB1高表达组5年生存率(54.84%)低于RREB1低表达组(74.42%),差异有统计学意义(χ^(2)=5.459,P=0.020);ANKRD1高表达组的5年生存率(78.79%)高于ANKRD1低表达组(55.56%),差异有统计学意义(χ^(2)=5.130,P=0.024)。RREB1高表达(HR=2.437,95%CI:1.113~4.684)、ANKRD1低表达(HR=0.573,95%CI:0.185~1.952)、TNM分期Ⅲ期(HR=2.202,95%CI:1.357~4.215)和淋巴结转移N1~N2(HR=1.247,95%CI:1.532~4.368)是CRC患者预后不良的危险因素(均P<0.05)。Spearman秩相关分析结果,CRC癌组织中RREB1与ANKRD1表达呈负相关(r=-0.389,P=0.036)。结论CRC癌组织中RREB1表达升高,而ANKRD1表达降低,二者共同参与CRC的发生发展,有望成为评估CRC患者预后的组织肿瘤标志物。展开更多
The internal region of bacterial translocatable IS1 acts as a cis-element to stimulate transcription from the various promoters located upstream. The product of the artA gene is genetically shown to stimulate transcri...The internal region of bacterial translocatable IS1 acts as a cis-element to stimulate transcription from the various promoters located upstream. The product of the artA gene is genetically shown to stimulate transcription with the cis-element. Here, a codon-optimized artA gene was synthesized and cloned to express the ArtA protein. ArtA was purified as the Histagged protein. Nitrocellulose filter binding assay showed that ArtA specifically binds to the IS1 internal region. Electrophoretic mobility shift assay also showed specific binding of ArtA to the IS1 internal region. These results imply that ArtA directly binds to the IS1 internal region and stimulates transcription.展开更多
Objective Schizophrenia(SZ)is associated with cognitive impairment,and it is known that the activity of cAMP response element binding protein(CREB)decreases in the brain of SZ patients.The previous study conducted by ...Objective Schizophrenia(SZ)is associated with cognitive impairment,and it is known that the activity of cAMP response element binding protein(CREB)decreases in the brain of SZ patients.The previous study conducted by the investigators revealed that the upregulation of CREB improves the MK801-related SZ cognitive deficit.The present study further investigates the mechanism on how CREB deficiency is associated with SZ-related cognitive impairment.Methods MK-801 was used to induce SZ in rats.Western blotting and immunofluorescence were performed to investigate CREB and the CREB-related pathway implicated in MK801 rats.The long-term potentiation and behavioral tests were performed to assess the synaptic plasticity and cognitive impairment,respectively.Results The phosphorylation of CREB at Ser133 decreased in the hippocampus of SZ rats.Interestingly,among the upstream kinases of CREB,merely ERK1/2 was downregulated,while CaMKII and PKA remained unchanged in the brain of MK801-related SZ rats.The inhibition of ERK1/2 by PD98059 reduced the phosphorylation of CREB-Ser133,and induced synaptic dysfunction in primary hippocampal neurons.Conversely,the activation of CREB attenuated the ERK1/2 inhibitor-induced synaptic and cognitive impairment.Conclusion These present findings partially suggest that the deficiency of the ERK1/2-CREB pathway is involved in MK801-related SZ cognitive impairment.The activation of the ERK1/2-CREB pathway may be therapeutically useful for treating SZ cognitive deficits.展开更多
文摘The molecular mechanism of how hepatocytes maintain cholesterol homeostasis has become much more transparent with the discovery of sterol regulatory element binding proteins (SREBPs) in recent years. These membrane proteins aremembers of the basic helix-loop-helix-leucine zipper (bHLHZip) family of transcription factors. They activate the expression of at least 30 genes involved in the synthesis of cholesterol and lipids. SREBPs are synthesized as precursor proteins in the endoplasmic reticulum (ER), where they form a complex with another protein, SREBP cleavage activating protein (SCAP). The SCAP molecule contains a sterol sensory domain. In the presence of high cellular sterol concentrations SCAP confines SREBP to the ER. With low cellular concentrations, SCAP escorts SREBP to activation in the Golgi. There, SREBP undergoes two proteolytic cleavage steps to release the mature, biologically active transcription factor, nuclear SREBP (nSREBP). nSREBP translocates to the nucleus and binds to sterol response elements (SRE) in the promoter/enhancer regions of target genes. Additional transcription factors are required to activate transcription of these genes. Three different SREBPs are known, SREBPs-1a, -1c and -2. SREBP-1a and -1c are isoforms produced from a single gene by alternate splicing. SREBP-2 is encoded by a different gene and does not display any isoforms. It appears that SREBPs alone, in the sequence described above, can exert complete control over cholesterol synthesis, whereas many additional factors (hormones, cytokines, etc.) are required for complete control of lipid metabolism. Medicinal manipulation of the SREBP/SCAP system is expected to prove highly beneficial in the management of cholesterol-related disease.
文摘目的探讨结直肠癌(colorectal cancer,CRC)组织ras反应元件结合蛋白1(ras-responsive element binding protein 1,RREB1),ankyrin重复结构域1(ankyrin repeat domain 1,ANKRD1)的表达及与临床病理特征和预后不良的关系。方法选取2013年1月~2016年12月复旦大学附属中山医院厦门医院收治的105例CRC患者,应用免疫组织化学SP法检测CRC患者癌组织和癌旁组织RREB1和ANKRD1蛋白表达,分析RREB1和ANKRD1蛋白表达与患者临床病理特征的关系,患者均随访5年,比较不同RREB1和ANKRD1表达患者的预后情况,并分析CRC患者预后不良的影响因素。采用Spearman相关系数分析RREB1与ANKRD1表达的相关性。结果CRC癌组织RREB1蛋白阳性率(59.05%)显著高于癌旁组织(27.61%),差异有统计学意义(χ^(2)=21.120,P=0.000)。CRC癌组织ANKRD1蛋白阳性率(31.43%)显著低于癌旁组织(60.95%),差异有统计学意义(χ^(2)=18.410,P=0.000)。TNM分期Ⅲ期、淋巴结转移N1~N2患者RREB1蛋白阳性率高于TNM分期Ⅰ~Ⅱ期、淋巴结转移N0患者,差异有统计学意义(χ^(2)=4.263,8.199,均P<0.05)。TNM分期Ⅲ期、淋巴结转移N1~N2患者ANKRD1蛋白阳性率低于TNM分期Ⅰ~Ⅱ期、淋巴结转移N0患者,差异有统计学意义(χ^(2)=5.515,7.411,均P<0.05)。RREB1高表达组5年生存率(54.84%)低于RREB1低表达组(74.42%),差异有统计学意义(χ^(2)=5.459,P=0.020);ANKRD1高表达组的5年生存率(78.79%)高于ANKRD1低表达组(55.56%),差异有统计学意义(χ^(2)=5.130,P=0.024)。RREB1高表达(HR=2.437,95%CI:1.113~4.684)、ANKRD1低表达(HR=0.573,95%CI:0.185~1.952)、TNM分期Ⅲ期(HR=2.202,95%CI:1.357~4.215)和淋巴结转移N1~N2(HR=1.247,95%CI:1.532~4.368)是CRC患者预后不良的危险因素(均P<0.05)。Spearman秩相关分析结果,CRC癌组织中RREB1与ANKRD1表达呈负相关(r=-0.389,P=0.036)。结论CRC癌组织中RREB1表达升高,而ANKRD1表达降低,二者共同参与CRC的发生发展,有望成为评估CRC患者预后的组织肿瘤标志物。
文摘The internal region of bacterial translocatable IS1 acts as a cis-element to stimulate transcription from the various promoters located upstream. The product of the artA gene is genetically shown to stimulate transcription with the cis-element. Here, a codon-optimized artA gene was synthesized and cloned to express the ArtA protein. ArtA was purified as the Histagged protein. Nitrocellulose filter binding assay showed that ArtA specifically binds to the IS1 internal region. Electrophoretic mobility shift assay also showed specific binding of ArtA to the IS1 internal region. These results imply that ArtA directly binds to the IS1 internal region and stimulates transcription.
基金supported in part by grants from National Natural Science Foundation of China(No.31929002,No.82201326 No.82071440 and No.92049107)Science,Technology and Innovation Commission of Shenzhen Municipality(No.JCYJ20210324141405014)+1 种基金Guangdong Basic and Applied Basic Research Foundation(No.2020B1515120017)the Academic Frontier Youth Team Project to Xiao-chuan WANG from Huazhong University of Science and Technology.
文摘Objective Schizophrenia(SZ)is associated with cognitive impairment,and it is known that the activity of cAMP response element binding protein(CREB)decreases in the brain of SZ patients.The previous study conducted by the investigators revealed that the upregulation of CREB improves the MK801-related SZ cognitive deficit.The present study further investigates the mechanism on how CREB deficiency is associated with SZ-related cognitive impairment.Methods MK-801 was used to induce SZ in rats.Western blotting and immunofluorescence were performed to investigate CREB and the CREB-related pathway implicated in MK801 rats.The long-term potentiation and behavioral tests were performed to assess the synaptic plasticity and cognitive impairment,respectively.Results The phosphorylation of CREB at Ser133 decreased in the hippocampus of SZ rats.Interestingly,among the upstream kinases of CREB,merely ERK1/2 was downregulated,while CaMKII and PKA remained unchanged in the brain of MK801-related SZ rats.The inhibition of ERK1/2 by PD98059 reduced the phosphorylation of CREB-Ser133,and induced synaptic dysfunction in primary hippocampal neurons.Conversely,the activation of CREB attenuated the ERK1/2 inhibitor-induced synaptic and cognitive impairment.Conclusion These present findings partially suggest that the deficiency of the ERK1/2-CREB pathway is involved in MK801-related SZ cognitive impairment.The activation of the ERK1/2-CREB pathway may be therapeutically useful for treating SZ cognitive deficits.
