The POU domain transcription factor Oct4 is a master regulator in maintaining self-renewal and pluripotency of embryonic stem （ES） cells. To further explore the functional network of Oct4, the yeast two-hybrid syste...The POU domain transcription factor Oct4 is a master regulator in maintaining self-renewal and pluripotency of embryonic stem （ES） cells. To further explore the functional network of Oct4, the yeast two-hybrid system was used to search for Oct4 interacting proteins. PH domain （containing POU domain and homeodomain） of human OCT4 was used as a bait. From the human testis cDNA library, we identified a strong interaction between OCT4 and karyopberin-alpha 2 （KPNA-2）. KPNA2 is involved in active nuclear import of proteins. This finding was confirmed by glutathione S-transferase pull-down and co-immunoprecipitation assays. The interaction between OCT4 and KPNA-2 was further mapped to multiple regions of the two proteins. In addition, we studied nuclear localization signal （NLS） of mouse Oct4 and demonstrated that it is essential for Oct4 nuclear localization. Thus, our data suggest that Oct4 nuclear localization may be mediated by its interaction with KPNA-2.展开更多
The nucleotide-binding and leucine-rich repeat(NLR)proteins comprise a major class of intracellular immune receptors that are capable of detecting pathogen-derived molecules and activating immunity and cell death in p...The nucleotide-binding and leucine-rich repeat(NLR)proteins comprise a major class of intracellular immune receptors that are capable of detecting pathogen-derived molecules and activating immunity and cell death in plants.The activity of some NLRs,particularly the Toll-like/interleukin-1 receptor(TIR)type,is highly correlated with their nucleocytoplasmic distribution.However,whether and how the nucleocytoplasmic homeostasis of NLRs is coordinated through a bidirectional nuclear shuttling mechanism remains unclear.Here,we identified a nuclear transport receptor,KA120,which is capable of affecting the nucleocytoplasmic distribution of an NLR protein and is essential in preventing its autoactivation.We showed that the ka120 mutant displays an autoimmune phenotype and NLR-induced transcriptome features.Through a targeted genetic screen using an artificial NLR microRNA library,we identified the TIR-NLR gene SNC1 as a genetic interactor of KA120.Loss-of-function snc1 mutations as well as compromising SNC1 protein activities all substantially suppressed ka120-induced autoimmune activation,and the enhanced SNC1 activity upon loss of KA120 functionappeared to occur at the protein level.Overexpression of KA120 efficiently repressed SNC1 activity and led to a nearly complete suppression of the autoimmune phenotype caused by the gain-of-function snc1-1 mutation or SNC1 overexpression in transgenic plants.Further florescence imaging analysis indicated that SNC1 undergoes altered nucleocytoplasmic distribution with significantly reduced nuclear signal when KA120 is constitutively expressed,supporting a role of KA120 in coordinating SNC1 nuclear abundance and activity.Consistently,compromising the SNC1 nuclear level by disrupting the nuclear pore complex could also partially rescue ka120-induced autoimmunity.Collectively,our study demonstrates that KA120 is essential to avoid autoimmune activation in the absence of pathogens and is required to constrain the nuclear activity of SNC1,possibly through coordinating SNC1 nucleocytoplasmic homeostasis as a potential mechanism.展开更多
Aim:Patients with glioblastomas demonstrate well‑documented immunological impairments including decreased numbers of mature dendritic cells(DCs).Recent data identified karyopherin a2(KPNA2),a nucleocytoplasmic shuttli...Aim:Patients with glioblastomas demonstrate well‑documented immunological impairments including decreased numbers of mature dendritic cells(DCs).Recent data identified karyopherin a2(KPNA2),a nucleocytoplasmic shuttling receptor,as diagnostic and prognostic biomarker for gliomas.The aim of this ongoing study is to correlate parameters of immunity and nucleocytoplasmic transport in glioblastoma patients.Methods:We preoperatively collected serum from 17 patients with glioblastomas and determined DC subsets(HLA DR+Lin-,CD34-,CD45+,CD123+,CD11+were analyzed)using a 6‑color flow cytometry panel.Expression levels of KPNA2 and nuclear accumulation of p53 were evaluated semi‑quantitatively by immunohistochemistry.O6‑methylguanine DNA methyltransferase(MGMT)and isocitrate dehydrogenase‑1(IDH‑1)status were assessed by pyrosequencing and immunohistochemistry,respectively.Results:Median expression levels for both KPNA2 and p53 were 5-10%.IDH‑1‑R132H mutation and MGMT promoter hypermethylation was detected in 3/16 and 1/9 patients,respectively.Mean counts of total mature DCs,myeloid DCs and plasmacytoid DCs were 9.6,2.1,3.4 cells/μL.A preliminary analysis suggests an association between low KPNA2 nuclear expression and increased numbers of mature DCs.However,this correlation did not reach statistical significance so far(P=0.077).Conclusion:Our preliminary data may indicate a role of KPNA2 in the impaired maturation of DCs observed in glioblastoma patients.展开更多
Nuclear accumulation of active Smad complexes is crucial for transduction of transforming growth factor β （TGF-β）- superfamily signals from transmembrane receptors into the nucleus. It is now clear that the nucleo...Nuclear accumulation of active Smad complexes is crucial for transduction of transforming growth factor β （TGF-β）- superfamily signals from transmembrane receptors into the nucleus. It is now clear that the nucleocytoplasmic distributions of Smads, in both the absence and the presence of a TGF-β-superfamily signal, are not static, but instead the Smads are continuously shuttling between the nucleus and the cytoplasm in both conditions. This article presents the evidence for continuous nucleocytoplasmic shuttling of Smads. It then reviews different mechanisms that have been proposed to mediate Smad nuclear import and export, and discusses how the Smad steady-state distributions in the absence and the presence of a TGF-β-superfamily signal are established. Finally, the biological relevance of continuous nucleocytoplasmic shuttling for signaling by TGF-β superfamily members is discussed.展开更多
目的探讨腺苷三磷酸结合区转运蛋白G超家族成员-2(ABCG2)基因失活前后hep-2细胞系中侧群细胞含量的差别。方法体外培养hep-2细胞,应用荧光染料Hoechst33342让对数期hep-2细胞进行染色,对照组加入荧光染料Hoechst33342及MDRI(多重耐药基...目的探讨腺苷三磷酸结合区转运蛋白G超家族成员-2(ABCG2)基因失活前后hep-2细胞系中侧群细胞含量的差别。方法体外培养hep-2细胞,应用荧光染料Hoechst33342让对数期hep-2细胞进行染色,对照组加入荧光染料Hoechst33342及MDRI(多重耐药基因multiple drug resistance)抑制剂维拉帕米,流式细胞仪检测SP细胞亚群含量;ABCG2-SiRNA转染hep-2细胞系后,应用荧光染料Hoechst33342对转染后细胞进行染色,对照组加入荧光染料Hoechst33342及维拉帕米,流式细胞仪检测SP细胞亚群含量,比较转染前后SP细胞亚群含量变化。结果 ABCG2-SiRNA转染前hep-2细胞Hoechst33342组SP细胞含量(3.15±0.32)%,Hoechst33342+维拉帕米组SP细胞含量(0.4±0.11)%;ABCG2-SiRNA转染后hep-2细胞Ho-echst33342组SP细胞含量(1.15±0.22)%,Hoechst33342+维拉帕米组SP细胞含量(0.0±0.09)%,转染后SP细胞亚群含量明显降低(P<0.05)。结论 ABCG2基因在喉癌SP细胞的发生发展过程中起重要作用,可能成为喉癌靶向治疗的潜在靶点。展开更多
基金supported by the Shanghai Science & Technology Developmental Foundations (No.06dj14001)the National High Technology Research and Development Program of China (No. 2006AA02Z197, 2006CB943901, and 2007CB947904)
文摘The POU domain transcription factor Oct4 is a master regulator in maintaining self-renewal and pluripotency of embryonic stem （ES） cells. To further explore the functional network of Oct4, the yeast two-hybrid system was used to search for Oct4 interacting proteins. PH domain （containing POU domain and homeodomain） of human OCT4 was used as a bait. From the human testis cDNA library, we identified a strong interaction between OCT4 and karyopberin-alpha 2 （KPNA-2）. KPNA2 is involved in active nuclear import of proteins. This finding was confirmed by glutathione S-transferase pull-down and co-immunoprecipitation assays. The interaction between OCT4 and KPNA-2 was further mapped to multiple regions of the two proteins. In addition, we studied nuclear localization signal （NLS） of mouse Oct4 and demonstrated that it is essential for Oct4 nuclear localization. Thus, our data suggest that Oct4 nuclear localization may be mediated by its interaction with KPNA-2.
基金X.Shen and X.Shi were supported by Tsinghua-Peking Joint Center tor Life SciencesThis project was supported by the USDA National Institute of Food and Agriculture(HATCH project CA-B-PLB-0243-H)+1 种基金the National Science Foundation(grant MCB-2049931)startup funds from Inno-vative Genomics Institute and University of California Berkeley.
文摘The nucleotide-binding and leucine-rich repeat(NLR)proteins comprise a major class of intracellular immune receptors that are capable of detecting pathogen-derived molecules and activating immunity and cell death in plants.The activity of some NLRs,particularly the Toll-like/interleukin-1 receptor(TIR)type,is highly correlated with their nucleocytoplasmic distribution.However,whether and how the nucleocytoplasmic homeostasis of NLRs is coordinated through a bidirectional nuclear shuttling mechanism remains unclear.Here,we identified a nuclear transport receptor,KA120,which is capable of affecting the nucleocytoplasmic distribution of an NLR protein and is essential in preventing its autoactivation.We showed that the ka120 mutant displays an autoimmune phenotype and NLR-induced transcriptome features.Through a targeted genetic screen using an artificial NLR microRNA library,we identified the TIR-NLR gene SNC1 as a genetic interactor of KA120.Loss-of-function snc1 mutations as well as compromising SNC1 protein activities all substantially suppressed ka120-induced autoimmune activation,and the enhanced SNC1 activity upon loss of KA120 functionappeared to occur at the protein level.Overexpression of KA120 efficiently repressed SNC1 activity and led to a nearly complete suppression of the autoimmune phenotype caused by the gain-of-function snc1-1 mutation or SNC1 overexpression in transgenic plants.Further florescence imaging analysis indicated that SNC1 undergoes altered nucleocytoplasmic distribution with significantly reduced nuclear signal when KA120 is constitutively expressed,supporting a role of KA120 in coordinating SNC1 nuclear abundance and activity.Consistently,compromising the SNC1 nuclear level by disrupting the nuclear pore complex could also partially rescue ka120-induced autoimmunity.Collectively,our study demonstrates that KA120 is essential to avoid autoimmune activation in the absence of pathogens and is required to constrain the nuclear activity of SNC1,possibly through coordinating SNC1 nucleocytoplasmic homeostasis as a potential mechanism.
文摘Aim:Patients with glioblastomas demonstrate well‑documented immunological impairments including decreased numbers of mature dendritic cells(DCs).Recent data identified karyopherin a2(KPNA2),a nucleocytoplasmic shuttling receptor,as diagnostic and prognostic biomarker for gliomas.The aim of this ongoing study is to correlate parameters of immunity and nucleocytoplasmic transport in glioblastoma patients.Methods:We preoperatively collected serum from 17 patients with glioblastomas and determined DC subsets(HLA DR+Lin-,CD34-,CD45+,CD123+,CD11+were analyzed)using a 6‑color flow cytometry panel.Expression levels of KPNA2 and nuclear accumulation of p53 were evaluated semi‑quantitatively by immunohistochemistry.O6‑methylguanine DNA methyltransferase(MGMT)and isocitrate dehydrogenase‑1(IDH‑1)status were assessed by pyrosequencing and immunohistochemistry,respectively.Results:Median expression levels for both KPNA2 and p53 were 5-10%.IDH‑1‑R132H mutation and MGMT promoter hypermethylation was detected in 3/16 and 1/9 patients,respectively.Mean counts of total mature DCs,myeloid DCs and plasmacytoid DCs were 9.6,2.1,3.4 cells/μL.A preliminary analysis suggests an association between low KPNA2 nuclear expression and increased numbers of mature DCs.However,this correlation did not reach statistical significance so far(P=0.077).Conclusion:Our preliminary data may indicate a role of KPNA2 in the impaired maturation of DCs observed in glioblastoma patients.
文摘Nuclear accumulation of active Smad complexes is crucial for transduction of transforming growth factor β （TGF-β）- superfamily signals from transmembrane receptors into the nucleus. It is now clear that the nucleocytoplasmic distributions of Smads, in both the absence and the presence of a TGF-β-superfamily signal, are not static, but instead the Smads are continuously shuttling between the nucleus and the cytoplasm in both conditions. This article presents the evidence for continuous nucleocytoplasmic shuttling of Smads. It then reviews different mechanisms that have been proposed to mediate Smad nuclear import and export, and discusses how the Smad steady-state distributions in the absence and the presence of a TGF-β-superfamily signal are established. Finally, the biological relevance of continuous nucleocytoplasmic shuttling for signaling by TGF-β superfamily members is discussed.
文摘目的探讨腺苷三磷酸结合区转运蛋白G超家族成员-2(ABCG2)基因失活前后hep-2细胞系中侧群细胞含量的差别。方法体外培养hep-2细胞,应用荧光染料Hoechst33342让对数期hep-2细胞进行染色,对照组加入荧光染料Hoechst33342及MDRI(多重耐药基因multiple drug resistance)抑制剂维拉帕米,流式细胞仪检测SP细胞亚群含量;ABCG2-SiRNA转染hep-2细胞系后,应用荧光染料Hoechst33342对转染后细胞进行染色,对照组加入荧光染料Hoechst33342及维拉帕米,流式细胞仪检测SP细胞亚群含量,比较转染前后SP细胞亚群含量变化。结果 ABCG2-SiRNA转染前hep-2细胞Hoechst33342组SP细胞含量(3.15±0.32)%,Hoechst33342+维拉帕米组SP细胞含量(0.4±0.11)%;ABCG2-SiRNA转染后hep-2细胞Ho-echst33342组SP细胞含量(1.15±0.22)%,Hoechst33342+维拉帕米组SP细胞含量(0.0±0.09)%,转染后SP细胞亚群含量明显降低(P<0.05)。结论 ABCG2基因在喉癌SP细胞的发生发展过程中起重要作用,可能成为喉癌靶向治疗的潜在靶点。
