BACKGROUND Adaptor protein,phosphotyrosine interacting with PH domain and leucine zipper 1(APPL1)plays a crucial role in regulating insulin signaling and glucose metabolism.Mutations in the APPL1 gene have been associ...BACKGROUND Adaptor protein,phosphotyrosine interacting with PH domain and leucine zipper 1(APPL1)plays a crucial role in regulating insulin signaling and glucose metabolism.Mutations in the APPL1 gene have been associated with the development of maturity-onset diabetes of the young type 14(MODY14).Currently,only two mutations[c.1655T>A(p.Leu552*)and c.281G>A p.(Asp94Asn)]have been identified in association with this disease.Given the limited understanding of MODY14,it is imperative to identify additional cases and carry out comprehensive research on MODY14 and APPL1 mutations.AIM To assess the pathogenicity of APPL1 gene mutations in diabetic patients and to characterize the functional role of the APPL1 domain.METHODS Patients exhibiting clinical signs and a medical history suggestive of MODY were screened for the study.Whole exome sequencing was performed on the patients as well as their family members.The pathogenicity of the identified APPL1 variants was predicted on the basis of bioinformatics analysis.In addition,the pathogenicity of the novel APPL1 variant was preliminarily evaluated through in vitro functional experiments.Finally,the impact of these variants on APPL1 protein expression and the insulin pathway were assessed,and the potential mechanism underlying the interaction between the APPL1 protein and the insulin receptor was further explored.RESULTS A total of five novel mutations were identified,including four missense mutations(Asp632Tyr,Arg633His,Arg532Gln,and Ile642Met)and one intronic mutation(1153-16A>T).Pathogenicity prediction analysis revealed that the Arg532Gln was pathogenic across all predictions.The Asp632Tyr and Arg633His variants also had pathogenicity based on MutationTaster.In addition,multiple alignment of amino acid sequences showed that the Arg532Gln,Asp632Tyr,and Arg633His variants were conserved across different species.Moreover,in in vitro functional experiments,both the c.1894G>T(at Asp632Tyr)and c.1595G>A(at Arg532Gln)mutations were found to downregulate the expression of APPL1 on both protein and mRNA levels,indicating their pathogenic nature.Therefore,based on the patient’s clinical and family history,combined with the results from bioinformatics analysis and functional experiment,the c.1894G>T(at Asp632Tyr)and c.1595G>A(at Arg532Gln)mutations were classified as pathogenic mutations.Importantly,all these mutations were located within the phosphotyrosinebinding domain of APPL1,which plays a critical role in the insulin sensitization effect.CONCLUSION This study provided new insights into the pathogenicity of APPL1 gene mutations in diabetes and revealed a potential target for the diagnosis and treatment of the disease.展开更多
目的:观察亮氨酸拉链EF-hand结构域跨膜蛋白1(leucine zipper/EF-hand-containing transmembrane protein 1,LETM1)在结肠癌中的表达情况,探讨LETM1蛋白是否能够成为判断结肠癌患者预后的新的生物学指标.方法:利用免疫组织化学法检测73...目的:观察亮氨酸拉链EF-hand结构域跨膜蛋白1(leucine zipper/EF-hand-containing transmembrane protein 1,LETM1)在结肠癌中的表达情况,探讨LETM1蛋白是否能够成为判断结肠癌患者预后的新的生物学指标.方法:利用免疫组织化学法检测73例结肠癌患者组织中LETM1蛋白的表达水平和蛋白激酶B(protein kinase B,PKB)/Akt的丝氨酸473(Ser473)、苏氨酸308(Thr308)两个磷酸化位点及葡萄糖合成激酶3β(glycogen synthase k i n a s e 3β,G S K3β)的磷酸化水平,并根据LETM1蛋白表达水平进行高表达和低表达分组;采用Kaplan-Meier法分析各组无疾病生存期;采用χ2检验进行组间单因素分析.结果:在结肠癌患者中LETM1蛋白高表达率为54.8%,LETM1蛋白在结肠癌浸润深度、分化及淋巴结转移中低表达和高表达率分别为27.3%/72.7%、38.3%/61.7%和22.7%/77.3%,其差异均有统计学意义(P<0.05),而与年龄、性别、肿瘤大小未见统计学意义(P>0.05).LETM1蛋白在结肠癌组织中可以激活磷脂酰肌醇3激酶(phosphatidylinositol 3 kinase,PI-3K)/A k t信号传导通路.L ETM1高表达患者无疾病生存期显著低于LETM1低表达患者(P<0.05).结论:LETM1蛋白在结肠癌中高表达,可能参与结肠癌的发生、发展与复发.LETM1蛋白可以作为预测结肠癌患者预后的新的生物学指标.展开更多
基金Supported by the National Natural Science Foundation,No.81974124and Taishan Scholar Project,No.tsqn20161071.
文摘BACKGROUND Adaptor protein,phosphotyrosine interacting with PH domain and leucine zipper 1(APPL1)plays a crucial role in regulating insulin signaling and glucose metabolism.Mutations in the APPL1 gene have been associated with the development of maturity-onset diabetes of the young type 14(MODY14).Currently,only two mutations[c.1655T>A(p.Leu552*)and c.281G>A p.(Asp94Asn)]have been identified in association with this disease.Given the limited understanding of MODY14,it is imperative to identify additional cases and carry out comprehensive research on MODY14 and APPL1 mutations.AIM To assess the pathogenicity of APPL1 gene mutations in diabetic patients and to characterize the functional role of the APPL1 domain.METHODS Patients exhibiting clinical signs and a medical history suggestive of MODY were screened for the study.Whole exome sequencing was performed on the patients as well as their family members.The pathogenicity of the identified APPL1 variants was predicted on the basis of bioinformatics analysis.In addition,the pathogenicity of the novel APPL1 variant was preliminarily evaluated through in vitro functional experiments.Finally,the impact of these variants on APPL1 protein expression and the insulin pathway were assessed,and the potential mechanism underlying the interaction between the APPL1 protein and the insulin receptor was further explored.RESULTS A total of five novel mutations were identified,including four missense mutations(Asp632Tyr,Arg633His,Arg532Gln,and Ile642Met)and one intronic mutation(1153-16A>T).Pathogenicity prediction analysis revealed that the Arg532Gln was pathogenic across all predictions.The Asp632Tyr and Arg633His variants also had pathogenicity based on MutationTaster.In addition,multiple alignment of amino acid sequences showed that the Arg532Gln,Asp632Tyr,and Arg633His variants were conserved across different species.Moreover,in in vitro functional experiments,both the c.1894G>T(at Asp632Tyr)and c.1595G>A(at Arg532Gln)mutations were found to downregulate the expression of APPL1 on both protein and mRNA levels,indicating their pathogenic nature.Therefore,based on the patient’s clinical and family history,combined with the results from bioinformatics analysis and functional experiment,the c.1894G>T(at Asp632Tyr)and c.1595G>A(at Arg532Gln)mutations were classified as pathogenic mutations.Importantly,all these mutations were located within the phosphotyrosinebinding domain of APPL1,which plays a critical role in the insulin sensitization effect.CONCLUSION This study provided new insights into the pathogenicity of APPL1 gene mutations in diabetes and revealed a potential target for the diagnosis and treatment of the disease.
文摘目的:观察亮氨酸拉链EF-hand结构域跨膜蛋白1(leucine zipper/EF-hand-containing transmembrane protein 1,LETM1)在结肠癌中的表达情况,探讨LETM1蛋白是否能够成为判断结肠癌患者预后的新的生物学指标.方法:利用免疫组织化学法检测73例结肠癌患者组织中LETM1蛋白的表达水平和蛋白激酶B(protein kinase B,PKB)/Akt的丝氨酸473(Ser473)、苏氨酸308(Thr308)两个磷酸化位点及葡萄糖合成激酶3β(glycogen synthase k i n a s e 3β,G S K3β)的磷酸化水平,并根据LETM1蛋白表达水平进行高表达和低表达分组;采用Kaplan-Meier法分析各组无疾病生存期;采用χ2检验进行组间单因素分析.结果:在结肠癌患者中LETM1蛋白高表达率为54.8%,LETM1蛋白在结肠癌浸润深度、分化及淋巴结转移中低表达和高表达率分别为27.3%/72.7%、38.3%/61.7%和22.7%/77.3%,其差异均有统计学意义(P<0.05),而与年龄、性别、肿瘤大小未见统计学意义(P>0.05).LETM1蛋白在结肠癌组织中可以激活磷脂酰肌醇3激酶(phosphatidylinositol 3 kinase,PI-3K)/A k t信号传导通路.L ETM1高表达患者无疾病生存期显著低于LETM1低表达患者(P<0.05).结论:LETM1蛋白在结肠癌中高表达,可能参与结肠癌的发生、发展与复发.LETM1蛋白可以作为预测结肠癌患者预后的新的生物学指标.
