Leaf color mutants (LCMs) provide crucial insights into the regulatory mechanisms underlying chloroplast development,photo synthesis,and stre ss adaptation.In this study,we identified a temperature-sensitive albino mu...Leaf color mutants (LCMs) provide crucial insights into the regulatory mechanisms underlying chloroplast development,photo synthesis,and stre ss adaptation.In this study,we identified a temperature-sensitive albino mutant,tsa4,characterized by an albino phenotype at the seedling stage and abnormal chloroplast development at temperatures below 25℃.展开更多
RAS家族的小鸟苷三磷酸酶(GTP酶)是受到严格调控的信号分子,其功能进一步受到泛素化和蛋白水解作用的调节。亮氨酸拉链样转录调节因子1(LZTR1)作为Cullin-3 RING E3泛素连接酶的底物适配分子,能够结合特定的RAS GTP酶并促进其泛素化和...RAS家族的小鸟苷三磷酸酶(GTP酶)是受到严格调控的信号分子,其功能进一步受到泛素化和蛋白水解作用的调节。亮氨酸拉链样转录调节因子1(LZTR1)作为Cullin-3 RING E3泛素连接酶的底物适配分子,能够结合特定的RAS GTP酶并促进其泛素化和蛋白酶体降解。本研究展示了与RIT1、MRAS和KRAS结合的LZTR1Kelch结构域的结构,揭示了控制RAS亚型选择性和核苷酸特异性的相互作用界面。对疾病相关的Kelch结构域突变的生化和结构分析揭示了3种改变类型:底物相互作用受损、环区稳定性降低以及结构片层间排斥作用增强。在细胞和小鼠模型中,破坏底物结合的突变再现了LZTR1缺失的表型,突显了其底物特异性。这些发现明确了LZTR1识别RAS的机制,并提出了一种降解致癌性KRAS的“分子胶”策略。展开更多
BACKGROUND Hepatocellular carcinoma(HCC)is a major health challenge with high incidence and poor survival rates in China.Systemic therapies,particularly tyrosine kinase inhibitors(TKIs),are the first-line treatment fo...BACKGROUND Hepatocellular carcinoma(HCC)is a major health challenge with high incidence and poor survival rates in China.Systemic therapies,particularly tyrosine kinase inhibitors(TKIs),are the first-line treatment for advanced HCC,but resistance is common.The Rho GTPase family member Rho GTPase activating protein 12(ARHGAP12),which regulates cell adhesion and invasion,is a potential therapeutic target for overcoming TKI resistance in HCC.However,no studies on the expression of ARHGAP12 in HCC and its role in resistance to TKIs have been reported.AIM To unveil the expression of ARHGAP12 in HCC,its role in TKI resistance and its potential associated pathways.METHODS This study used single-cell RNA sequencing(scRNA-seq)to evaluate ARHGAP12 mRNA levels and explored its mechanisms through enrichment analysis.CellChat was used to investigate focal adhesion(FA)pathway regulation.We integrated bulk RNA data(RNA-seq and microarray),immunohistochemistry and proteomics to analyze ARHGAP12 mRNA and protein levels,correlating with clinical outcomes.We assessed ARHGAP12 expression in TKI-resistant HCC,integrated conventional HCC to explore its mechanism,identified intersecting FA pathway genes with scRNA-seq data and evaluated its response to TKI and immunotherapy.RESULTS ARHGAP12 mRNA was found to be highly expressed in malignant hepatocytes and to regulate FA.In malignant hepatocytes in high-score FA groups,MDK-[integrin alpha 6(ITGA6)+integrinβ-1(ITGB1)]showed specificity in ligand-receptor interactions.ARHGAP12 mRNA and protein were upregulated in bulk RNA,immunohistochemistry and proteomics,and higher expression was associated with a worse prognosis.ARHGAP12 was also found to be a TKI resistance gene that regulated the FA pathway.ITGB1 was identified as a crossover gene in the FA pathway in both scRNA-seq and bulk RNA.High expression of ARHGAP12 was associated with adverse reactions to sorafenib,cabozantinib and regorafenib,but not to immunotherapy.CONCLUSION ARHGAP12 expression is elevated in HCC and TKI-resistant HCC,and its regulatory role in FA may underlie the TKI-resistant phenotype.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant Nos.32341026 and 32171998)the Hunan Provincial Science and Technology Innovation Program,China(Grant No.2023NK1010)the Changsha Natural Science Foundation,China(Grant No.20209001).
文摘Leaf color mutants (LCMs) provide crucial insights into the regulatory mechanisms underlying chloroplast development,photo synthesis,and stre ss adaptation.In this study,we identified a temperature-sensitive albino mutant,tsa4,characterized by an albino phenotype at the seedling stage and abnormal chloroplast development at temperatures below 25℃.
文摘RAS家族的小鸟苷三磷酸酶(GTP酶)是受到严格调控的信号分子,其功能进一步受到泛素化和蛋白水解作用的调节。亮氨酸拉链样转录调节因子1(LZTR1)作为Cullin-3 RING E3泛素连接酶的底物适配分子,能够结合特定的RAS GTP酶并促进其泛素化和蛋白酶体降解。本研究展示了与RIT1、MRAS和KRAS结合的LZTR1Kelch结构域的结构,揭示了控制RAS亚型选择性和核苷酸特异性的相互作用界面。对疾病相关的Kelch结构域突变的生化和结构分析揭示了3种改变类型:底物相互作用受损、环区稳定性降低以及结构片层间排斥作用增强。在细胞和小鼠模型中,破坏底物结合的突变再现了LZTR1缺失的表型,突显了其底物特异性。这些发现明确了LZTR1识别RAS的机制,并提出了一种降解致癌性KRAS的“分子胶”策略。
基金Supported by National Natural Science Foundation of China,No.82260581Guangxi Zhuang Autonomous Region Health Committee Scientific Research Project,No.Z20201147+3 种基金Guangxi Medical University Education and Teaching Reform Project,No.2021XJGA02Undergraduate Teaching Reform Project of Guangxi Higher Education,No.2023JGB163Guangxi Medical University Teacher Teaching Ability Development Project,No.2202JFA20China Undergraduate Innovation and Entrepreneurship Training Program,No.S202310598170.
文摘BACKGROUND Hepatocellular carcinoma(HCC)is a major health challenge with high incidence and poor survival rates in China.Systemic therapies,particularly tyrosine kinase inhibitors(TKIs),are the first-line treatment for advanced HCC,but resistance is common.The Rho GTPase family member Rho GTPase activating protein 12(ARHGAP12),which regulates cell adhesion and invasion,is a potential therapeutic target for overcoming TKI resistance in HCC.However,no studies on the expression of ARHGAP12 in HCC and its role in resistance to TKIs have been reported.AIM To unveil the expression of ARHGAP12 in HCC,its role in TKI resistance and its potential associated pathways.METHODS This study used single-cell RNA sequencing(scRNA-seq)to evaluate ARHGAP12 mRNA levels and explored its mechanisms through enrichment analysis.CellChat was used to investigate focal adhesion(FA)pathway regulation.We integrated bulk RNA data(RNA-seq and microarray),immunohistochemistry and proteomics to analyze ARHGAP12 mRNA and protein levels,correlating with clinical outcomes.We assessed ARHGAP12 expression in TKI-resistant HCC,integrated conventional HCC to explore its mechanism,identified intersecting FA pathway genes with scRNA-seq data and evaluated its response to TKI and immunotherapy.RESULTS ARHGAP12 mRNA was found to be highly expressed in malignant hepatocytes and to regulate FA.In malignant hepatocytes in high-score FA groups,MDK-[integrin alpha 6(ITGA6)+integrinβ-1(ITGB1)]showed specificity in ligand-receptor interactions.ARHGAP12 mRNA and protein were upregulated in bulk RNA,immunohistochemistry and proteomics,and higher expression was associated with a worse prognosis.ARHGAP12 was also found to be a TKI resistance gene that regulated the FA pathway.ITGB1 was identified as a crossover gene in the FA pathway in both scRNA-seq and bulk RNA.High expression of ARHGAP12 was associated with adverse reactions to sorafenib,cabozantinib and regorafenib,but not to immunotherapy.CONCLUSION ARHGAP12 expression is elevated in HCC and TKI-resistant HCC,and its regulatory role in FA may underlie the TKI-resistant phenotype.
