Leucine-rich repeat kinase 1 （LRRK1） plays a critical role in regulating cytoskeletal organization, osteoclast activity, and bone resorption with little effect on bone formation parameters. Deficiency of Lrrkl in mi...Leucine-rich repeat kinase 1 （LRRK1） plays a critical role in regulating cytoskeletal organization, osteoclast activity, and bone resorption with little effect on bone formation parameters. Deficiency of Lrrkl in mice causes a severe osteopetrosis in the metaphysis of the long bones and vertebrae bones, which makes LRRK1 an attractive alternative drug target for the treatment of osteoporosis and other high-turnover bone diseases. This review recent advances on the functions of the Lrrkl-related family members, Lrrkl deficiency-induced skeletal phenotypes, LRRK1 structure-function, potential biological substrates and interacting proteins, and the mechanisms of LRRK1 action in osteoclasts.展开更多
Background:Kirsten rat sarcoma(KRAS)and mutant KRAS^(G12D)have been implicated in human cancers,but it remains unclear whether their activation requires ubiquitination.This study aimed to investigate whether and how F...Background:Kirsten rat sarcoma(KRAS)and mutant KRAS^(G12D)have been implicated in human cancers,but it remains unclear whether their activation requires ubiquitination.This study aimed to investigate whether and how F-box and leucine-rich repeat 6(FBXL6)regulates KRAS and KRAS^(G12D)activity in hepatocellular carcinoma(HCC).Methods:We constructed transgenic mouse strains LC(LSL-Fbxl6^(KI/+);Alb-Cre,n=13),KC(LSL-Kras^(G12D/+);Alb-Cre,n=10)and KLC(LSL-Kras^(G12D/+);LSL-Fbxl6^(KI/+);Alb-Cre,n=12)mice,and then monitored HCC for 320 d.Multiomics approaches and pharmacological inhibitors were used to determine oncogenic signaling in the context of elevated FBXL6 and KRAS activation.Co-immunoprecipitation(Co-IP),Western blotting,ubiquitination assay,and RAS activity detection assay were employed to investigate the underlying molecular mechanism by which FBXL6 activates KRAS.The pathological relevance of the FBXL6/KRAS/extracellular signal-regulated kinase(ERK)/mammalian target of rapamycin(mTOR)/proteins of relevant evolutionary and lymphoid interest domain 2(PRELID2)axis was evaluated in 129 paired samples from HCC patients.Results:FBXL6 is highly expressed in HCC as well as other human cancers(P<0.001).Interestingly,FBXL6 drives HCC in transgenic mice.Mechanistically,elevated FBXL6 promotes the polyubiquitination of both wild-type KRAS and KRAS^(G12D)at lysine 128,leading to the activation of both KRAS and KRAS^(G12D)and promoting their binding to the serine/threonine-protein kinase RAF,which is followed by the activation of mitogen-activated protein kinase kinase(MEK)/ERK/mTOR signaling.The oncogenic activity of the MEK/ERK/mTOR axis relies on PRELID2,which induces reactive oxygen species(ROS)generation.Furthermore,hepatic FBXL6 upregulation facilitates KRAS^(G12D)to induce more severe hepatocarcinogenesis and lung metastasis via the MEK/ERK/mTOR/PRELID2/ROS axis.Dual inhibition of MEK and mTOR effectively suppresses tumor growth and metastasis in this subtype of cancer in vivo.In clinical samples,FBXL6 expression positively correlates with p-ERK(χ^(2)=85.067,P<0.001),p-mTOR(χ^(2)=66.919,P<0.001)and PRELID2(χ^(2)=20.891,P<0.001).The Kaplan-Meier survival analyses suggested that HCC patients with high FBXL6/p-ERK levels predicted worse overall survival(log-rank P<0.001).Conclusions:FBXL6 activates KRAS or KRAS^(G12D)via ubiquitination at the site K128,leading to activation of the ERK/mTOR/PRELID2/ROS axis and tumorigenesis.Dual inhibition of MEK and mTOR effectively protects against FBXL6-and KRAS^(G12D)-induced tumorigenesis,providing a potential therapeutic strategy to treat this aggressive subtype of liver cancer.展开更多
含sushi重复蛋白X连锁2(sushi repeat-containing protein X-linked 2,SRPX2)是一种分子质量约为53 k D,具有细胞外基质蛋白属性的硫酸软骨素蛋白聚糖,在大脑语言中枢的发育过程中发挥重要作用。目前研究发现,SRPX2在多种恶性肿瘤组织...含sushi重复蛋白X连锁2(sushi repeat-containing protein X-linked 2,SRPX2)是一种分子质量约为53 k D,具有细胞外基质蛋白属性的硫酸软骨素蛋白聚糖,在大脑语言中枢的发育过程中发挥重要作用。目前研究发现,SRPX2在多种恶性肿瘤组织中呈高表达,参与肿瘤细胞的增殖、迁移、黏附和侵袭等生物学行为,促进肿瘤的发生和发展,与肿瘤患者的不良预后密切相关。另有研究显示,SRPX2可通过诱导内皮细胞迁移和血管网形成,从而促进血管生成。因此认为,SRPX2是一个潜在的肿瘤治疗靶点。本文对SRPX2的结构、生物学特征、相关疾病以及在肿瘤中的生物学作用及其机制进行综述。展开更多
The G2019S mutation of the leucine-rich repeat kinase 2(LRRK2)is the most common genetic cause of Parkinson's disease (PD).However,the molecular mechanisms of LRRK2 mutation contributing to the onset and progressi...The G2019S mutation of the leucine-rich repeat kinase 2(LRRK2)is the most common genetic cause of Parkinson's disease (PD).However,the molecular mechanisms of LRRK2 mutation contributing to the onset and progression of PD have not been fully illustrated.We generated HEK293 cells stably transfected with α-synuclein and investigated the effect of LRRK2 G2019S mutation on the degradation of α-synuclein.The lysosomal activity was assessed by the protein degradation of glyceraldehyde-3-phosphate dehydrogenase and ribonuclease A.It was found that α-synuclein was mainly degraded in lysosomes.LRRK2G2019S inhibited the degradation of α-synuclein,and promoted its aggregation.LRRK2G 2019S also decreased the activities of lysosomal enzymes including cathepsin B and cathepsin L.Furthermore,the inhibitory effect of LRRK2 G2019S on lysosomal functions did not depend on its kinase activity.These findings indicated that the inhibitory effect of LRRK2 G2019S on α-synuclein degradation could underlie the pathogenesis of aberrant α-synuclein aggregation in PD with LRRK2 mutation.展开更多
基金supported by National Institutes of Health grant AR066831-01ASBMR GAP grant to Weirong R Xingsupported by a senior research career scientist award from the Department of Veteran’s Affairs
文摘Leucine-rich repeat kinase 1 （LRRK1） plays a critical role in regulating cytoskeletal organization, osteoclast activity, and bone resorption with little effect on bone formation parameters. Deficiency of Lrrkl in mice causes a severe osteopetrosis in the metaphysis of the long bones and vertebrae bones, which makes LRRK1 an attractive alternative drug target for the treatment of osteoporosis and other high-turnover bone diseases. This review recent advances on the functions of the Lrrkl-related family members, Lrrkl deficiency-induced skeletal phenotypes, LRRK1 structure-function, potential biological substrates and interacting proteins, and the mechanisms of LRRK1 action in osteoclasts.
基金supported by the National Natural Science Foundation of China(82370631)the Talent Foundations from Army Medical University(4174C6),the Chongqing Government(CQYC20220303727)to Xie CMthe National Natural Science Foundation of China(31900449)to Xiong HJ.
文摘Background:Kirsten rat sarcoma(KRAS)and mutant KRAS^(G12D)have been implicated in human cancers,but it remains unclear whether their activation requires ubiquitination.This study aimed to investigate whether and how F-box and leucine-rich repeat 6(FBXL6)regulates KRAS and KRAS^(G12D)activity in hepatocellular carcinoma(HCC).Methods:We constructed transgenic mouse strains LC(LSL-Fbxl6^(KI/+);Alb-Cre,n=13),KC(LSL-Kras^(G12D/+);Alb-Cre,n=10)and KLC(LSL-Kras^(G12D/+);LSL-Fbxl6^(KI/+);Alb-Cre,n=12)mice,and then monitored HCC for 320 d.Multiomics approaches and pharmacological inhibitors were used to determine oncogenic signaling in the context of elevated FBXL6 and KRAS activation.Co-immunoprecipitation(Co-IP),Western blotting,ubiquitination assay,and RAS activity detection assay were employed to investigate the underlying molecular mechanism by which FBXL6 activates KRAS.The pathological relevance of the FBXL6/KRAS/extracellular signal-regulated kinase(ERK)/mammalian target of rapamycin(mTOR)/proteins of relevant evolutionary and lymphoid interest domain 2(PRELID2)axis was evaluated in 129 paired samples from HCC patients.Results:FBXL6 is highly expressed in HCC as well as other human cancers(P<0.001).Interestingly,FBXL6 drives HCC in transgenic mice.Mechanistically,elevated FBXL6 promotes the polyubiquitination of both wild-type KRAS and KRAS^(G12D)at lysine 128,leading to the activation of both KRAS and KRAS^(G12D)and promoting their binding to the serine/threonine-protein kinase RAF,which is followed by the activation of mitogen-activated protein kinase kinase(MEK)/ERK/mTOR signaling.The oncogenic activity of the MEK/ERK/mTOR axis relies on PRELID2,which induces reactive oxygen species(ROS)generation.Furthermore,hepatic FBXL6 upregulation facilitates KRAS^(G12D)to induce more severe hepatocarcinogenesis and lung metastasis via the MEK/ERK/mTOR/PRELID2/ROS axis.Dual inhibition of MEK and mTOR effectively suppresses tumor growth and metastasis in this subtype of cancer in vivo.In clinical samples,FBXL6 expression positively correlates with p-ERK(χ^(2)=85.067,P<0.001),p-mTOR(χ^(2)=66.919,P<0.001)and PRELID2(χ^(2)=20.891,P<0.001).The Kaplan-Meier survival analyses suggested that HCC patients with high FBXL6/p-ERK levels predicted worse overall survival(log-rank P<0.001).Conclusions:FBXL6 activates KRAS or KRAS^(G12D)via ubiquitination at the site K128,leading to activation of the ERK/mTOR/PRELID2/ROS axis and tumorigenesis.Dual inhibition of MEK and mTOR effectively protects against FBXL6-and KRAS^(G12D)-induced tumorigenesis,providing a potential therapeutic strategy to treat this aggressive subtype of liver cancer.
文摘含sushi重复蛋白X连锁2(sushi repeat-containing protein X-linked 2,SRPX2)是一种分子质量约为53 k D,具有细胞外基质蛋白属性的硫酸软骨素蛋白聚糖,在大脑语言中枢的发育过程中发挥重要作用。目前研究发现,SRPX2在多种恶性肿瘤组织中呈高表达,参与肿瘤细胞的增殖、迁移、黏附和侵袭等生物学行为,促进肿瘤的发生和发展,与肿瘤患者的不良预后密切相关。另有研究显示,SRPX2可通过诱导内皮细胞迁移和血管网形成,从而促进血管生成。因此认为,SRPX2是一个潜在的肿瘤治疗靶点。本文对SRPX2的结构、生物学特征、相关疾病以及在肿瘤中的生物学作用及其机制进行综述。
基金the National Natura Science Foundation of China(NSFC)(No.81401051,No 81671051,and No.81501107).
文摘The G2019S mutation of the leucine-rich repeat kinase 2(LRRK2)is the most common genetic cause of Parkinson's disease (PD).However,the molecular mechanisms of LRRK2 mutation contributing to the onset and progression of PD have not been fully illustrated.We generated HEK293 cells stably transfected with α-synuclein and investigated the effect of LRRK2 G2019S mutation on the degradation of α-synuclein.The lysosomal activity was assessed by the protein degradation of glyceraldehyde-3-phosphate dehydrogenase and ribonuclease A.It was found that α-synuclein was mainly degraded in lysosomes.LRRK2G2019S inhibited the degradation of α-synuclein,and promoted its aggregation.LRRK2G 2019S also decreased the activities of lysosomal enzymes including cathepsin B and cathepsin L.Furthermore,the inhibitory effect of LRRK2 G2019S on lysosomal functions did not depend on its kinase activity.These findings indicated that the inhibitory effect of LRRK2 G2019S on α-synuclein degradation could underlie the pathogenesis of aberrant α-synuclein aggregation in PD with LRRK2 mutation.
