Brassinosteroids(BRs)are essential phytohormones that broadly regulate plant growth,development,and adaptation to biotic and abiotic stresses.In Arabidopsis,apoplastic BR molecules are perceived by a plasma membrane-l...Brassinosteroids(BRs)are essential phytohormones that broadly regulate plant growth,development,and adaptation to biotic and abiotic stresses.In Arabidopsis,apoplastic BR molecules are perceived by a plasma membrane-localized receptor complex comprising the ligand-binding receptor BRI1 and the co-receptor BAK1.While negative regulators of the BR receptor complex,such as BKI1,BIR3,and PUB12/13,have been well characterized,how BRI1 and BAK1 are positively modulated in the BR pathway remains largely unknown.In this study,a genetic screen involving overexpression of RLP genes in the bak1-3 bkk1-1 double mutant reveals that enhanced RLP51 expression partially suppresses the BR-deficient phenotypes of bak1-3 bkk1-1.RLP51 overexpression also partially rescues the weak bri1 mutant allele,bri1-301.Although the rlp51 single mutant exhibits wild-type-like phenotypes,it enhances BR-defective phenotypes in bri1-301 and bak1 serk1 mutants.RLP51 is next found to interact with both BRI1 and BAK1 without affecting BRI1–BAK1 interaction.Critically,co-expression of RLP51 with BRI1 or BAK1 significantly increases BRI1 and BAK1 protein abundances.RLP51 appears to promote protein synthesis rather than stabilize BRI1 and BAK1 proteins.Thus,our study identifies RLP51 as a positive regulator of BR signaling that enhances the protein levels of BRI1 and BAK1.展开更多
目的:探讨核因子-κB(Nuclear factor kappa B,NF-κB)介导的促凋亡蛋白Bak(Bcl-2 associated K protein gene,Bak)及TNF-α的表达在溃疡性结肠炎(Ulcerative colitis,UC)发病中的作用机制。方法:选购80只清洁级SD大鼠,分为模型组和对...目的:探讨核因子-κB(Nuclear factor kappa B,NF-κB)介导的促凋亡蛋白Bak(Bcl-2 associated K protein gene,Bak)及TNF-α的表达在溃疡性结肠炎(Ulcerative colitis,UC)发病中的作用机制。方法:选购80只清洁级SD大鼠,分为模型组和对照组。UC大鼠模型制造采用"三硝基苯磺酸+乙醇"方法,模型制造成功后观察、评估结肠黏膜的大体形态及组织学变化。用免疫组织化学及RT-PCR法检测模型组与对照组中的NF-κB、Bak、TNF-α的表达水平,并分析相互之间关系。结果:UC大鼠模型制造成功率为97%。模型组固有层和黏膜层内炎性细胞浸润较对照组明显增多(P<0.01);NF-κB、TNF-α蛋白及mRNA表达水平模型组较对照组明显升高(P<0.01);Bak蛋白在模型组的炎细胞中表达明显低于对照组(P<0.01),而在结肠黏膜上皮细胞中的水平与对照组无明显差异(P>0.05)。NF-κB、TNF-α蛋白阳性细胞百分数及mRNA水平随模型组的组织学等级升高而增强,而Bak蛋白阳性细胞百分数是减弱的(P<0.05);且模型组中NF-κB与Bak蛋白的表达水平呈负相关(r=-0.793,P<0.01),NF-κB与TNF-α蛋白表达成正相关(r=0.892,P<0.01)。结论:NF-κB介导的促凋亡蛋白Bak的表达参与了UC的发生、发展。展开更多
基金supported by the National Natural Science Foundation of China(32370295 and 32170280 to K.H.)Foundation of Science and Technology of Gansu Province(22ZD6NA049)+3 种基金the Fundamental Research Funds for the Central Universities(lzujbky-2021-kb05 to Y.F.and lzujbky-2023-kb05 to P.L.)the Science and Technology Department of Gansu Province(24JRRA392 to K.H.and 23JRRA1132 to C.X.)China Postdoctoral Science Foundation(2024M751259 and GZB20240285 to B.L.)Science and Technology Program of Gansu Province(25JRRA718 to B.L.).
文摘Brassinosteroids(BRs)are essential phytohormones that broadly regulate plant growth,development,and adaptation to biotic and abiotic stresses.In Arabidopsis,apoplastic BR molecules are perceived by a plasma membrane-localized receptor complex comprising the ligand-binding receptor BRI1 and the co-receptor BAK1.While negative regulators of the BR receptor complex,such as BKI1,BIR3,and PUB12/13,have been well characterized,how BRI1 and BAK1 are positively modulated in the BR pathway remains largely unknown.In this study,a genetic screen involving overexpression of RLP genes in the bak1-3 bkk1-1 double mutant reveals that enhanced RLP51 expression partially suppresses the BR-deficient phenotypes of bak1-3 bkk1-1.RLP51 overexpression also partially rescues the weak bri1 mutant allele,bri1-301.Although the rlp51 single mutant exhibits wild-type-like phenotypes,it enhances BR-defective phenotypes in bri1-301 and bak1 serk1 mutants.RLP51 is next found to interact with both BRI1 and BAK1 without affecting BRI1–BAK1 interaction.Critically,co-expression of RLP51 with BRI1 or BAK1 significantly increases BRI1 and BAK1 protein abundances.RLP51 appears to promote protein synthesis rather than stabilize BRI1 and BAK1 proteins.Thus,our study identifies RLP51 as a positive regulator of BR signaling that enhances the protein levels of BRI1 and BAK1.
文摘目的:探讨核因子-κB(Nuclear factor kappa B,NF-κB)介导的促凋亡蛋白Bak(Bcl-2 associated K protein gene,Bak)及TNF-α的表达在溃疡性结肠炎(Ulcerative colitis,UC)发病中的作用机制。方法:选购80只清洁级SD大鼠,分为模型组和对照组。UC大鼠模型制造采用"三硝基苯磺酸+乙醇"方法,模型制造成功后观察、评估结肠黏膜的大体形态及组织学变化。用免疫组织化学及RT-PCR法检测模型组与对照组中的NF-κB、Bak、TNF-α的表达水平,并分析相互之间关系。结果:UC大鼠模型制造成功率为97%。模型组固有层和黏膜层内炎性细胞浸润较对照组明显增多(P<0.01);NF-κB、TNF-α蛋白及mRNA表达水平模型组较对照组明显升高(P<0.01);Bak蛋白在模型组的炎细胞中表达明显低于对照组(P<0.01),而在结肠黏膜上皮细胞中的水平与对照组无明显差异(P>0.05)。NF-κB、TNF-α蛋白阳性细胞百分数及mRNA水平随模型组的组织学等级升高而增强,而Bak蛋白阳性细胞百分数是减弱的(P<0.05);且模型组中NF-κB与Bak蛋白的表达水平呈负相关(r=-0.793,P<0.01),NF-κB与TNF-α蛋白表达成正相关(r=0.892,P<0.01)。结论:NF-κB介导的促凋亡蛋白Bak的表达参与了UC的发生、发展。
