AIM: To study preliminarily the properties of myosin light chain kinase (MLCK) in rabbit liver. METHODS: The expression of MLCK was detected by reverse transcription-polymerase chain reaction(RT-PCR); the MLCK was obt...AIM: To study preliminarily the properties of myosin light chain kinase (MLCK) in rabbit liver. METHODS: The expression of MLCK was detected by reverse transcription-polymerase chain reaction(RT-PCR); the MLCK was obtained from rabbit liver, and its activity was analyzed by gamma-(32)P incorporation technique to detect the phosphorylation of myosin light chain. RESULTS: MLCK was expressed in rabbit liver, and the activity of the enzyme was similar to rabbit smooth muscle MLCK, and calmodulin-dependent. When the concentration was 0.65 mg x L(-1), the activity was at the highest level. CONCLUSION: MLCK expressed in rabbit liver may catalyze the phosphorylation of myosin light chain, which may play important roles in the regulation of hepatic cell functions.展开更多
Objective To investigate role and mechanism of phosphate myosin light chain ( pMLC) in rat kidney of chronic allograft nephropathy ( CAN) model. Methods Left donor kidneys from Fisher ( F344) rats were ortho-topically...Objective To investigate role and mechanism of phosphate myosin light chain ( pMLC) in rat kidney of chronic allograft nephropathy ( CAN) model. Methods Left donor kidneys from Fisher ( F344) rats were ortho-topically transplanted into Lewis recipients,Meanwhile, F344 rats and LEW rats with resection of right展开更多
The aim of this short review is to describe the role of myosin isoforms during the adaptation of skeletal muscle to prolonged physical activity (for example endurance exercise) and to show the coordination between cha...The aim of this short review is to describe the role of myosin isoforms during the adaptation of skeletal muscle to prolonged physical activity (for example endurance exercise) and to show the coordination between changes in muscle oxidative capacity and myofibrillar apparatus in slow-twitch and fast-twitch muscles. Adaptational changes in myosin isoforms during long lasting muscle activity (decrease of MyHC IIb isoforms relative content and increase of that MyHC IIa and decrease of MyLC 1 fast isoforms in fast-twitch muscles) are in good coordination with changes of muscle oxidative capacity. These changes show that during regular endurance exercise fast-twitch muscle fibers (type IIA) are also recruited and create the potential source of increase in endurance capacity during the process of adaptation to the prolonged physical activity.展开更多
Inhibition of protein tyrosine phosphatase by orthovanadate induces vasoconstriction, which is mediated by the Rho kinase-dependent inactivation of myosin light chain phosphatase (MLCP) via signaling downstream of Src...Inhibition of protein tyrosine phosphatase by orthovanadate induces vasoconstriction, which is mediated by the Rho kinase-dependent inactivation of myosin light chain phosphatase (MLCP) via signaling downstream of Src-induced activation of the epidermal growth factor (EGF) receptor. The present study investigated the potential role of EGF in orthovanadate (OVA)-dependent vaso-constriction. OVA-induced aortic contraction significantly increased in the presence of EGF, and was abolished by inhibitors of Rho kinase (Y27632), extracellular signal-regulated kinase 1 and 2 (Erk1/2) (FR180204), Erk1/2 kinase (PD98059), EGF receptor (AG1478), and Src (PP2). Treatment of the rat endothelium-denuded thoracic aorta with either EGF or OVA augmented the phosphorylation of myosin phosphatase target subunit 1 (MYPT1) at Thr-853 and of the EGF receptor at Tyr-1173. The phosphorylation of MYPT1 was further increased by co-stimulation with EGF and OVA. EGF receptor phosphorylation at Tyr-845 was also increased by EGF or OVA;this effect was augmented by co-stimulation with EGF and OVA, and was abolished by Src inhibition. In addition, Erk1/2 was phosphorylated by EGF or by co-treatment with EGF and OVA;this was abolished by an EGF receptor inhibitor, but not by Src inhibition. These results suggested that OVA-induced EGF-related contraction was mediated by the Rho kinase-dependent inactivation of MLCP via two different signaling cascades: Src-dependent phosphorylation of the EGF receptor at Tyr-845 and EGF-dependent phosphorylation of Erk1/2.展开更多
目的构建肌球蛋白轻链激酶(MLCK)敲除的下咽癌FaDu细胞株,并探讨敲除MLCK对FaDu细胞凋亡的影响。方法脂质体转染sgRNA和Cas92NLS Nuclease构建MLCK敲除的FaDu细胞株,提DNA测序确定敲除细胞株,分为对照组、MLCK KO 1组、MLCK KO 2组;采用...目的构建肌球蛋白轻链激酶(MLCK)敲除的下咽癌FaDu细胞株,并探讨敲除MLCK对FaDu细胞凋亡的影响。方法脂质体转染sgRNA和Cas92NLS Nuclease构建MLCK敲除的FaDu细胞株,提DNA测序确定敲除细胞株,分为对照组、MLCK KO 1组、MLCK KO 2组;采用RT-qPCR、Western blot检测MLCK敲除效率;流式细胞术检测MLCK敲除对细胞周期和凋亡的影响;Western blot检测MLCK敲除对细胞凋亡的影响。结果DNA测序显示在sgRNA序列识别处,MLCK碱基序列发生了缺失或替换;RT-qPCR和Western blot显示MLCK敲除细胞株mRNA和蛋白质水平低于对照组(P<0.0001);流式细胞术实验显示敲除MLCK对FaDu细胞的周期无明显变化,但凋亡率增加(P<0.0001);Western blot检测显示,MLCK敲除组Bax/Bcl-2(P<0.0001)和Cleaved Caspase-3/Caspase-3(P=0.0007)增加。结论敲除MLCK诱导细胞凋亡,但具体机制需进一步研究。展开更多
In the course of analysis of single fibers randomly excided from the fast and slow muscles of the rat for myosin light chain patterns, we have found that the light chains of all fibers taken from extensor digitorum lo...In the course of analysis of single fibers randomly excided from the fast and slow muscles of the rat for myosin light chain patterns, we have found that the light chains of all fibers taken from extensor digitorum longus (EDL) show the same as but different from those of fibers taken from soleus (Sol) in pattern. This characteristic differentiation of展开更多
基金Supported by the National Natural Science Foundation of China(39870324,YW)Key Innovation Project of Chinese Academy of Science,P.R.China(KSCX 2-2-01,XB Yao)Grant for Excellent Young Teachers of Ministry of Education of China(99044312,YW)
文摘AIM: To study preliminarily the properties of myosin light chain kinase (MLCK) in rabbit liver. METHODS: The expression of MLCK was detected by reverse transcription-polymerase chain reaction(RT-PCR); the MLCK was obtained from rabbit liver, and its activity was analyzed by gamma-(32)P incorporation technique to detect the phosphorylation of myosin light chain. RESULTS: MLCK was expressed in rabbit liver, and the activity of the enzyme was similar to rabbit smooth muscle MLCK, and calmodulin-dependent. When the concentration was 0.65 mg x L(-1), the activity was at the highest level. CONCLUSION: MLCK expressed in rabbit liver may catalyze the phosphorylation of myosin light chain, which may play important roles in the regulation of hepatic cell functions.
文摘Objective To investigate role and mechanism of phosphate myosin light chain ( pMLC) in rat kidney of chronic allograft nephropathy ( CAN) model. Methods Left donor kidneys from Fisher ( F344) rats were ortho-topically transplanted into Lewis recipients,Meanwhile, F344 rats and LEW rats with resection of right
文摘The aim of this short review is to describe the role of myosin isoforms during the adaptation of skeletal muscle to prolonged physical activity (for example endurance exercise) and to show the coordination between changes in muscle oxidative capacity and myofibrillar apparatus in slow-twitch and fast-twitch muscles. Adaptational changes in myosin isoforms during long lasting muscle activity (decrease of MyHC IIb isoforms relative content and increase of that MyHC IIa and decrease of MyLC 1 fast isoforms in fast-twitch muscles) are in good coordination with changes of muscle oxidative capacity. These changes show that during regular endurance exercise fast-twitch muscle fibers (type IIA) are also recruited and create the potential source of increase in endurance capacity during the process of adaptation to the prolonged physical activity.
文摘Inhibition of protein tyrosine phosphatase by orthovanadate induces vasoconstriction, which is mediated by the Rho kinase-dependent inactivation of myosin light chain phosphatase (MLCP) via signaling downstream of Src-induced activation of the epidermal growth factor (EGF) receptor. The present study investigated the potential role of EGF in orthovanadate (OVA)-dependent vaso-constriction. OVA-induced aortic contraction significantly increased in the presence of EGF, and was abolished by inhibitors of Rho kinase (Y27632), extracellular signal-regulated kinase 1 and 2 (Erk1/2) (FR180204), Erk1/2 kinase (PD98059), EGF receptor (AG1478), and Src (PP2). Treatment of the rat endothelium-denuded thoracic aorta with either EGF or OVA augmented the phosphorylation of myosin phosphatase target subunit 1 (MYPT1) at Thr-853 and of the EGF receptor at Tyr-1173. The phosphorylation of MYPT1 was further increased by co-stimulation with EGF and OVA. EGF receptor phosphorylation at Tyr-845 was also increased by EGF or OVA;this effect was augmented by co-stimulation with EGF and OVA, and was abolished by Src inhibition. In addition, Erk1/2 was phosphorylated by EGF or by co-treatment with EGF and OVA;this was abolished by an EGF receptor inhibitor, but not by Src inhibition. These results suggested that OVA-induced EGF-related contraction was mediated by the Rho kinase-dependent inactivation of MLCP via two different signaling cascades: Src-dependent phosphorylation of the EGF receptor at Tyr-845 and EGF-dependent phosphorylation of Erk1/2.
文摘In the course of analysis of single fibers randomly excided from the fast and slow muscles of the rat for myosin light chain patterns, we have found that the light chains of all fibers taken from extensor digitorum longus (EDL) show the same as but different from those of fibers taken from soleus (Sol) in pattern. This characteristic differentiation of
