The polar, sub-cellular localization of PIN auxin efflux carriers determines the direction of intercellular auxin flow, thus defining the spatial aspect of auxin signalling. Dynamic, transcytosis-like relocalizations ...The polar, sub-cellular localization of PIN auxin efflux carriers determines the direction of intercellular auxin flow, thus defining the spatial aspect of auxin signalling. Dynamic, transcytosis-like relocalizations of PIN proteins occur in response to external and internal signals, integrating these signals into changes in auxin distribution. Here, we examine the cellular and molecular mechanisms of polar PIN delivery and transcytosis. The mechanisms of the ARF-GEF-dependent polar targeting and transcytosis are well conserved and show little variations among diverse Arabidopsis ecotypes consistent with their fundamental importance in regulating plant development. At the cellular level, we refine previous findings on the role of the actin cytoskeleton in apical and basal PIN targeting, and identify a previously unknown role for microtubules, specifically in basal targeting. PIN protein delivery to different sides of the cell is mediated by ARFdependent trafficking with a previously unknown complex level of distinct ARF-GEF vesicle trafficking regulators. Our data suggest that alternative recruitment of PIN proteins by these distinct pathways can account for cell type- and cargo-specific aspects of polar targeting, as well as for polarity changes in response to different signals. The resulting dynamic PIN positioning to different sides of cells defines a three-dimensional pattern of auxin fluxes within plant tissues.展开更多
Polar auxin transport, which is required for the formation of auxin gradients and directional auxin flows that are critical for plant pattern formation, morphogenesis, and directional growth response to vectorial cues...Polar auxin transport, which is required for the formation of auxin gradients and directional auxin flows that are critical for plant pattern formation, morphogenesis, and directional growth response to vectorial cues, is mediated by polarized sub-cellular distribution of PIN-FORMED Proteins （PINs, auxin efflux carriers）, AUX1/AUXI-like proteins （auxin influx facilitators）, and multidrug resistance P-glycoproteins （MDR/PGP）. Polar localization of these proteins is controlled by both developmental and environmental cues. Recent studies have revealed cellular （endocytosis, transcytosis, and endosomal sorting and recycling） and molecular （PINOID kinase, protein phosphatase 2A） mechanisms underlying the polar distribution of these auxin transport proteins. Both TIR1-mediated auxin signaling and TIRl-independent auxinmediated endocytosis have been shown to regulate polar PIN localization and auxin flow, implicating auxin as a selforganizing signal in directing polar transport and directional flows.展开更多
Background:Human myxovirus resistant protein A(MxA),encoded by the myxovirus resistance 1(Mx1) gene,is an interferon(IFN)-triggered dynamin-like multi-domain GTPase involved in innate immune responses against viral in...Background:Human myxovirus resistant protein A(MxA),encoded by the myxovirus resistance 1(Mx1) gene,is an interferon(IFN)-triggered dynamin-like multi-domain GTPase involved in innate immune responses against viral infections.Recent studies suggest that MxA is associated with several human cancers and may be a tumor suppressor and a promising biomarker for IFN therapy.Mxl gene mutations in the coding region for MxA have been discovered in many types of cancer,suggesting potential biological associations between mutations in MxA protein and corresponding cancers.In this study,we performed a systematic analysis based on the crystal structures of MxA and elucidated how these mutations specifically affect the structure and therefore the function of MxA protein.Methods:Cancer-associated Mxl mutations were collected and screened from the COSMIC database.Twenty-two unique mutations that cause single amino acid alterations in the MxA protein were chosen for the analysis.Amino acid sequence alignment was performed using Clustal W to check the conservation level of mutation sites in Mx proteins and dynamins.Structural analysis of the mutants was carried out with Coot.Structural models of selected mutants were generated by the SWISS-MODEL server for comparison with the corresponding non-mutated structures.All structural figures were generated using PyMOL.Results:We analyzed the conservation level of the single-point mutation sites and mapped them on different domains of MxA.Through individual structural analysis,we found that some mutations severely affect the stability and function of MxA either by disrupting the intraVinter-molecular interactions supported by the original residues or by incurring unfavorable configuration alterations,whereas other mutations lead to gentle or no interference to the protein stability and function because of positions or polarity features.The potential clinical value of the mutations that lead to drastic influence on MxA protein is also assessed.Conclusions:Among all of the reported tumor-as展开更多
Asip is a mammalian homologue of polarity protein Par-3 of Caenorhabditis elegans and Bazooka of Drosophila melanogaster. Asip/Par-3/Bazooka are PDZ-motif containing proteins that localize asymmetrically to the cell p...Asip is a mammalian homologue of polarity protein Par-3 of Caenorhabditis elegans and Bazooka of Drosophila melanogaster. Asip/Par-3/Bazooka are PDZ-motif containing proteins that localize asymmetrically to the cell periphery and play a pivotal role in cell polarity and asymmetric cell division. In the present study, we have cloned human asip cDNA and its splicing variants by 5’-RACE and RT-PCR using candidate human EST clones which have a high homology to rat asip cDNA. The full-length cDNA of human asip encodes a 1,353 aa protein exhibiting 88% similarity to the rat one. Human asip is a single copy gene consisting of at least 26 exons and localizing in human chromosome 10, band p11.2, with some extraordinarily long introns. All exon/intron boundary nucleotides conform to the "gt-ag" rule. Three main transcripts were detected by Northern blot analysis, and at least five variants, from alternative splicing and polyadenylation, have been identified by RT-PCR and liver cDNA library screening. Exon 17b deleted asip mRNAs expressed ubiquitously in normal human tissues, including liver, on RT-PCR analysis. However, they were absent from most human liver cancer cell lines examined. More interestingly, the expression of exon 1 7b deleted variants was down regulated in 52.6% (10/19) clinic specimens of human hepatocellular carcinomas (HCCs), compared with the surrounding nontumorous liver tissues from the same patients. The presence of various splicing transcripts, the variation of their distribution among different tissues and cells, and their differential expressions in human HCCs suggest that human Asip isoforms may function in different context.展开更多
目的:检测肝细胞肝癌(hepatocellular carcinoma,HCC)癌组织、癌旁组织(adjacent normal liver tissue,ANLT)及不同侵袭能力细胞系中极性蛋白AF-6 m RNA的表达情况,分析其在不同组织及不同细胞系中的表达差异及意义.方法:利用实时定量PC...目的:检测肝细胞肝癌(hepatocellular carcinoma,HCC)癌组织、癌旁组织(adjacent normal liver tissue,ANLT)及不同侵袭能力细胞系中极性蛋白AF-6 m RNA的表达情况,分析其在不同组织及不同细胞系中的表达差异及意义.方法:利用实时定量PCR检测(real-time quantitative,q RT-PCR)检测AF-6 m RNA在3 0对癌组织、A N LT和4种细胞系(L 0 2、Hep G2、MHCC97-H和HCCLM3)中的表达情况.结果:AF-6 m RNA在93.3%(28/30)的HCC中呈低表达;正常肝细胞株L02中AF-6 m RNA含量明显高于肝癌细胞株(P<0.05);高侵袭转移能力的细胞系MHCC97-H及HCCLM3只有极低的AF-6 m RNA表达,且明显低于低侵袭转移能力的细胞系Hep G2(P<0.05).结论:AF-6 m RNA在肝癌中的低表达可能与高侵袭能力相关,提示AF-6 m RNA在将来可能会成为治疗侵袭性HCC的潜在靶点.展开更多
Protein arginine methyltransferase 7(PRMT7)is closely related to the formation of lung cancer,breast cancer and other malignant tumors,and it may be a potential target gene for malignant tumor therapy.Dishevelleds(DVL...Protein arginine methyltransferase 7(PRMT7)is closely related to the formation of lung cancer,breast cancer and other malignant tumors,and it may be a potential target gene for malignant tumor therapy.Dishevelleds(DVLs)are key factors involved in cell proliferation,invasion and metastasis.Among the dishevelleds,the dishevelled segment polarity protein 3(DVL3)is a key protein in the Wnt signaling pathway,and its abnormal expression plays an important role in the occurrence and development of malignant tumors.This paper reviewed the advances in research of PRMT7 and DVL3 in gastric cancer.展开更多
In the past two decades, extensive studies have focused on a group of so-called polarity proteins that play conserved and essential functions in establishing and maintaining cell polarity in epithelial cells. Among th...In the past two decades, extensive studies have focused on a group of so-called polarity proteins that play conserved and essential functions in establishing and maintaining cell polarity in epithelial cells. Among them, Crumbs （Crb） is the only trans- membrane polarity protein characterized to date （Tepass et al.,展开更多
文摘The polar, sub-cellular localization of PIN auxin efflux carriers determines the direction of intercellular auxin flow, thus defining the spatial aspect of auxin signalling. Dynamic, transcytosis-like relocalizations of PIN proteins occur in response to external and internal signals, integrating these signals into changes in auxin distribution. Here, we examine the cellular and molecular mechanisms of polar PIN delivery and transcytosis. The mechanisms of the ARF-GEF-dependent polar targeting and transcytosis are well conserved and show little variations among diverse Arabidopsis ecotypes consistent with their fundamental importance in regulating plant development. At the cellular level, we refine previous findings on the role of the actin cytoskeleton in apical and basal PIN targeting, and identify a previously unknown role for microtubules, specifically in basal targeting. PIN protein delivery to different sides of the cell is mediated by ARFdependent trafficking with a previously unknown complex level of distinct ARF-GEF vesicle trafficking regulators. Our data suggest that alternative recruitment of PIN proteins by these distinct pathways can account for cell type- and cargo-specific aspects of polar targeting, as well as for polarity changes in response to different signals. The resulting dynamic PIN positioning to different sides of cells defines a three-dimensional pattern of auxin fluxes within plant tissues.
文摘Polar auxin transport, which is required for the formation of auxin gradients and directional auxin flows that are critical for plant pattern formation, morphogenesis, and directional growth response to vectorial cues, is mediated by polarized sub-cellular distribution of PIN-FORMED Proteins （PINs, auxin efflux carriers）, AUX1/AUXI-like proteins （auxin influx facilitators）, and multidrug resistance P-glycoproteins （MDR/PGP）. Polar localization of these proteins is controlled by both developmental and environmental cues. Recent studies have revealed cellular （endocytosis, transcytosis, and endosomal sorting and recycling） and molecular （PINOID kinase, protein phosphatase 2A） mechanisms underlying the polar distribution of these auxin transport proteins. Both TIR1-mediated auxin signaling and TIRl-independent auxinmediated endocytosis have been shown to regulate polar PIN localization and auxin flow, implicating auxin as a selforganizing signal in directing polar transport and directional flows.
基金supported by research grants from the National Natural Science Foundation of China(No.31200553)the National Basic Research Program of China(No.2013CB910500)+1 种基金the Program of New Century Excellent Talents in University(NCET-12-0567)the Recruitment Program for Young Professionals
文摘Background:Human myxovirus resistant protein A(MxA),encoded by the myxovirus resistance 1(Mx1) gene,is an interferon(IFN)-triggered dynamin-like multi-domain GTPase involved in innate immune responses against viral infections.Recent studies suggest that MxA is associated with several human cancers and may be a tumor suppressor and a promising biomarker for IFN therapy.Mxl gene mutations in the coding region for MxA have been discovered in many types of cancer,suggesting potential biological associations between mutations in MxA protein and corresponding cancers.In this study,we performed a systematic analysis based on the crystal structures of MxA and elucidated how these mutations specifically affect the structure and therefore the function of MxA protein.Methods:Cancer-associated Mxl mutations were collected and screened from the COSMIC database.Twenty-two unique mutations that cause single amino acid alterations in the MxA protein were chosen for the analysis.Amino acid sequence alignment was performed using Clustal W to check the conservation level of mutation sites in Mx proteins and dynamins.Structural analysis of the mutants was carried out with Coot.Structural models of selected mutants were generated by the SWISS-MODEL server for comparison with the corresponding non-mutated structures.All structural figures were generated using PyMOL.Results:We analyzed the conservation level of the single-point mutation sites and mapped them on different domains of MxA.Through individual structural analysis,we found that some mutations severely affect the stability and function of MxA either by disrupting the intraVinter-molecular interactions supported by the original residues or by incurring unfavorable configuration alterations,whereas other mutations lead to gentle or no interference to the protein stability and function because of positions or polarity features.The potential clinical value of the mutations that lead to drastic influence on MxA protein is also assessed.Conclusions:Among all of the reported tumor-as
基金research grants fromthe Special Grant for Human Genomics Program ofChinese Academy of Sciences and the Special Fundsfor Ma
文摘Asip is a mammalian homologue of polarity protein Par-3 of Caenorhabditis elegans and Bazooka of Drosophila melanogaster. Asip/Par-3/Bazooka are PDZ-motif containing proteins that localize asymmetrically to the cell periphery and play a pivotal role in cell polarity and asymmetric cell division. In the present study, we have cloned human asip cDNA and its splicing variants by 5’-RACE and RT-PCR using candidate human EST clones which have a high homology to rat asip cDNA. The full-length cDNA of human asip encodes a 1,353 aa protein exhibiting 88% similarity to the rat one. Human asip is a single copy gene consisting of at least 26 exons and localizing in human chromosome 10, band p11.2, with some extraordinarily long introns. All exon/intron boundary nucleotides conform to the "gt-ag" rule. Three main transcripts were detected by Northern blot analysis, and at least five variants, from alternative splicing and polyadenylation, have been identified by RT-PCR and liver cDNA library screening. Exon 17b deleted asip mRNAs expressed ubiquitously in normal human tissues, including liver, on RT-PCR analysis. However, they were absent from most human liver cancer cell lines examined. More interestingly, the expression of exon 1 7b deleted variants was down regulated in 52.6% (10/19) clinic specimens of human hepatocellular carcinomas (HCCs), compared with the surrounding nontumorous liver tissues from the same patients. The presence of various splicing transcripts, the variation of their distribution among different tissues and cells, and their differential expressions in human HCCs suggest that human Asip isoforms may function in different context.
文摘目的:检测肝细胞肝癌(hepatocellular carcinoma,HCC)癌组织、癌旁组织(adjacent normal liver tissue,ANLT)及不同侵袭能力细胞系中极性蛋白AF-6 m RNA的表达情况,分析其在不同组织及不同细胞系中的表达差异及意义.方法:利用实时定量PCR检测(real-time quantitative,q RT-PCR)检测AF-6 m RNA在3 0对癌组织、A N LT和4种细胞系(L 0 2、Hep G2、MHCC97-H和HCCLM3)中的表达情况.结果:AF-6 m RNA在93.3%(28/30)的HCC中呈低表达;正常肝细胞株L02中AF-6 m RNA含量明显高于肝癌细胞株(P<0.05);高侵袭转移能力的细胞系MHCC97-H及HCCLM3只有极低的AF-6 m RNA表达,且明显低于低侵袭转移能力的细胞系Hep G2(P<0.05).结论:AF-6 m RNA在肝癌中的低表达可能与高侵袭能力相关,提示AF-6 m RNA在将来可能会成为治疗侵袭性HCC的潜在靶点.
基金Supported by Chengde Medical University-National Natural Science Foundation of China Project Cultivation Fund (202114)Chengde Medical UniversitySchool-level Key Project Fund (201711)+1 种基金Key Discipline Construction Project of Hebei Province [Ji Jiao Gao (2013) No. 4:Pathology and Pathophysiology]Master Candidate Innovation Ability Training Funding Project of Hebei Province (CXZZSS2022141)
文摘Protein arginine methyltransferase 7(PRMT7)is closely related to the formation of lung cancer,breast cancer and other malignant tumors,and it may be a potential target gene for malignant tumor therapy.Dishevelleds(DVLs)are key factors involved in cell proliferation,invasion and metastasis.Among the dishevelleds,the dishevelled segment polarity protein 3(DVL3)is a key protein in the Wnt signaling pathway,and its abnormal expression plays an important role in the occurrence and development of malignant tumors.This paper reviewed the advances in research of PRMT7 and DVL3 in gastric cancer.
基金supported by the grants from the National Institutes of Health of USA(NCRR R21RR024869, NIGMS RO1GM086423 and RO1GM121534 to Y.H.)the Start-up Foundation from Nanjing Medical University (2012RC04 to J.H.)University of Pittsburgh Medical School Center for Biologic Imaging was supported by the grant 1S100D019973-01 from NIH, USA
文摘In the past two decades, extensive studies have focused on a group of so-called polarity proteins that play conserved and essential functions in establishing and maintaining cell polarity in epithelial cells. Among them, Crumbs （Crb） is the only trans- membrane polarity protein characterized to date （Tepass et al.,
