Dynamin-related protein 1属于动力蛋白GTP酶超家族,是线粒体分裂体系的组成成分,在线粒体分裂中具有重要作用。在不同物种中,dynamin-related protein 1在与多种分子相互作用后,可以定位于线粒体并组装成高级结构,引起膜的收缩和分裂...Dynamin-related protein 1属于动力蛋白GTP酶超家族,是线粒体分裂体系的组成成分,在线粒体分裂中具有重要作用。在不同物种中,dynamin-related protein 1在与多种分子相互作用后,可以定位于线粒体并组装成高级结构,引起膜的收缩和分裂。Dynamin-related protein 1功能的消失会增强线粒体的融合和线粒体之间的连通性。Dynamin-related protein 1在细胞凋亡等多种细胞功能中也具有重要作用。展开更多
Electroacupuncture preconditioning at acupoint Baihui （GV20） can reduce focal cerebral ischemia/reperfusion injury. However, the precise protective mechanism remains unknown. Mitochondrial fission mediated by dynami...Electroacupuncture preconditioning at acupoint Baihui （GV20） can reduce focal cerebral ischemia/reperfusion injury. However, the precise protective mechanism remains unknown. Mitochondrial fission mediated by dynamin-related protein 1 （Drp1） can trigger neuronal apoptosis following cerebral ischemia/reperfusion injury. Herein, we examined the hypothesis that electroacupuncture pretreatment can regulate Drp1, and thus inhibit mitochondrial fission to provide cerebral protection. Rat models of focal cerebral ischemia/reperfusion injury were established by middle cerebral artery occlusion at 24 hours after 5 consecutive days of preconditioning with electroacupuncture at GV20 （depth 2 mm, intensity 1 mA, frequency 2/15 Hz, for 30 minutes, once a day）. Neurological function was assessed using the Longa neurological deficit score. Pathological changes in the ischemic penumbra on the injury side were assessed by hematoxylin-eosin staining. Cellular apoptosis in the ischemic penumbra on the injury side was assessed by terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end labeling staining. Mitochondrial ultrastructure in the ischemic penumbra on the injury side was assessed by transmission electron microscopy. Drp1 and cytochrome c expression in the ischemic penumbra on the injury side were assessed by western blot assay. Results showed that electroacupuncture preconditioning decreased expression of total and mitochondrial Drp1, decreased expression of total and cytosolic cytochrome c, maintained mitochondrial morphology and reduced the proportion of apoptotic cells in the ischemic penumbra on the injury side, with associated improvements in neurological function. These data suggest that electroacupuncture preconditioning-induced neuronal protection involves inhibition of the expression and translocation of Drp1.展开更多
Objective Formation of the endophilin II-Ca 2＋ channel complex is Ca 2＋ -dependent in clathrin-mediated endocytosis. However, little is known about whether the other two endophilin isoforms have the same features. T...Objective Formation of the endophilin II-Ca 2＋ channel complex is Ca 2＋ -dependent in clathrin-mediated endocytosis. However, little is known about whether the other two endophilin isoforms have the same features. The present study aimed to investigate the characteristics of the interactions of all three isoforms with Ca 2＋ channels and dynamin I. Methods N-type Ca 2＋ channel C-terminal fragments （NCFs） synthesized with a 3 H-leucine-labeled kit, were incubated with endophilin-GST fusion proteins, followed by pull-down assay. Results were counted on a scintillation counter. In addition, the different endophilin isoforms were each co-transfected with dynamin I into 293T cells, followed by flow cytometry and co-immunoprecipitation assay. Immunostaining was performed and an image analysis program was used to evaluate the overlap coefficient of cells expressing endophilin and dynamin I. Results All three isoforms interacted with NCF. Endophilins I and II demonstrated clear Ca 2＋ -dependent interactions with NCF, whereas endophilin III did not. Co-immunoprecipitation showed that, compared to endophilin I/II, the interaction between endophilin III and dynamin I was significantly increased. Similar results were obtained from flow cytometry. Furthermore, endophilin III had a higher overlap coefficient with dynamin I in co-transfected 293T cells. Conclusion Endophilin isoforms have distinct characteristics in interactions with NCF and dynamin I. Endophilin III binding to NCF is Ca 2＋ -independent, implying that it plays a different role in clathrin-mediated endocytosis.展开更多
The current study examined a rat model of vascular dementia. The model rats exhibited obvious morphological and ultrastructural changes in neurons in the brain, and significantly reduced dynamin 1 expression in hippoc...The current study examined a rat model of vascular dementia. The model rats exhibited obvious morphological and ultrastructural changes in neurons in the brain, and significantly reduced dynamin 1 expression in hippocampal CA1 region along with decreased learning and memory performance. Following atorvastatin treatment, the morphology and ultrastructure of cells in the model rat brain were significantly improved, dynamin 1 expression in hippocampal CA1 region was significantly enhanced, and learning and memory ability was significantly improved. The results demonstrated that impaired learning and memory abilities in vascular dementia model rats were closely correlated with decreased dynamin 1 expression. These findings indicate that atorvastatin can protect model rats against cognitive impairment by increasing dynamin 1 expression.展开更多
FcαR, the Fc receptor for IgA, is essential for IgA-mediated immune responses. Previous studies have shown that IgA and IgA immune complexes can be rapidly endocytosed by FcαR. However, the underlying mechanism rema...FcαR, the Fc receptor for IgA, is essential for IgA-mediated immune responses. Previous studies have shown that IgA and IgA immune complexes can be rapidly endocytosed by FcαR. However, the underlying mechanism remains unclear. Here, we investigated the endocytic pathway of FcαR in monocytic cell line, U937, that naturally express FcuR and in transfected Chinese hamster ovary （CHO）, COS-7 and Hela cells. By using selective chemical inhibitors of different endocytic pathways, overexpression of dominant-negative mutants of Eps15 and knockdown of clathrin heavy chain （CHC） via RNA interference, we demonstrated that endocytosis of FcaR was through a clathrin-mediated pathway. The endocytosed FcαR went into Rab5- and Rabll-positive endosomes. However, endocytosis of FcaR could not be blocked by a dominant-negative mutant of Rab5. We also demonstrated that endocytosis of FcαR was dynamin-dependent by overexpressing a dominant-negative mutant of dynamin. The potential endocytic motif for FcαR was also examined. Unexpectedly, we found that the entire cytoplasmic domain of FcaR was not required for the endocytic process of FcαR. We conclude that endocytosis of FcaR is clathrin- and dynamin-dependent, but is not regulated by RabS, and the endocytic motif is not located in the cytoplasmic domain of FcαR.展开更多
Autophagy is a central lysosomal degradation pathway required for maintaining cellular homeostasis and its dysfunction is associated with numerous human diseases. To identify players in autophagy, we tested ~ 1200 che...Autophagy is a central lysosomal degradation pathway required for maintaining cellular homeostasis and its dysfunction is associated with numerous human diseases. To identify players in autophagy, we tested ~ 1200 chemically induced mutations on the X chromosome in Drosophila fat body clones and discovered that shibire （shi） plays an essential role in starvation-induced autophagy, shi encodes a dynamin protein required for fission of clathrin-coated vesicles from the plasma membrane during endocytosis. We showed that Shi is dispensable for autophagy initiation and autophagosome--lysosome fusion, but required for lysosomal/autolysosomal acidification. We also showed that other endocytic core machinery components like clathrin and AP2 play similar but not identical roles in regulating autophagy and lysosomal function as dynamin. Previous studies suggested that dynamin directly regulates autophagosome formation and autophagic lysosome reformation （ALR） through its excision activity, Here, we provide evidence that dynamin also regulates autophagy indirectly by regulating lysosomal function.展开更多
文摘Dynamin-related protein 1属于动力蛋白GTP酶超家族,是线粒体分裂体系的组成成分,在线粒体分裂中具有重要作用。在不同物种中,dynamin-related protein 1在与多种分子相互作用后,可以定位于线粒体并组装成高级结构,引起膜的收缩和分裂。Dynamin-related protein 1功能的消失会增强线粒体的融合和线粒体之间的连通性。Dynamin-related protein 1在细胞凋亡等多种细胞功能中也具有重要作用。
基金supported by the Natural Science Foundation of Shandong Province of China,No.ZR2015HM023a grant from the Science and Technology Plan Project of Shinan District of Qingdao City of China,No.2016-3-029-YY
文摘Electroacupuncture preconditioning at acupoint Baihui （GV20） can reduce focal cerebral ischemia/reperfusion injury. However, the precise protective mechanism remains unknown. Mitochondrial fission mediated by dynamin-related protein 1 （Drp1） can trigger neuronal apoptosis following cerebral ischemia/reperfusion injury. Herein, we examined the hypothesis that electroacupuncture pretreatment can regulate Drp1, and thus inhibit mitochondrial fission to provide cerebral protection. Rat models of focal cerebral ischemia/reperfusion injury were established by middle cerebral artery occlusion at 24 hours after 5 consecutive days of preconditioning with electroacupuncture at GV20 （depth 2 mm, intensity 1 mA, frequency 2/15 Hz, for 30 minutes, once a day）. Neurological function was assessed using the Longa neurological deficit score. Pathological changes in the ischemic penumbra on the injury side were assessed by hematoxylin-eosin staining. Cellular apoptosis in the ischemic penumbra on the injury side was assessed by terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end labeling staining. Mitochondrial ultrastructure in the ischemic penumbra on the injury side was assessed by transmission electron microscopy. Drp1 and cytochrome c expression in the ischemic penumbra on the injury side were assessed by western blot assay. Results showed that electroacupuncture preconditioning decreased expression of total and mitochondrial Drp1, decreased expression of total and cytosolic cytochrome c, maintained mitochondrial morphology and reduced the proportion of apoptotic cells in the ischemic penumbra on the injury side, with associated improvements in neurological function. These data suggest that electroacupuncture preconditioning-induced neuronal protection involves inhibition of the expression and translocation of Drp1.
基金supported by grants from the National Natural Science Foundation of China (30870785)the Natural Science Foundation of Guangdong Province, China (9351008901000003)
文摘Objective Formation of the endophilin II-Ca 2＋ channel complex is Ca 2＋ -dependent in clathrin-mediated endocytosis. However, little is known about whether the other two endophilin isoforms have the same features. The present study aimed to investigate the characteristics of the interactions of all three isoforms with Ca 2＋ channels and dynamin I. Methods N-type Ca 2＋ channel C-terminal fragments （NCFs） synthesized with a 3 H-leucine-labeled kit, were incubated with endophilin-GST fusion proteins, followed by pull-down assay. Results were counted on a scintillation counter. In addition, the different endophilin isoforms were each co-transfected with dynamin I into 293T cells, followed by flow cytometry and co-immunoprecipitation assay. Immunostaining was performed and an image analysis program was used to evaluate the overlap coefficient of cells expressing endophilin and dynamin I. Results All three isoforms interacted with NCF. Endophilins I and II demonstrated clear Ca 2＋ -dependent interactions with NCF, whereas endophilin III did not. Co-immunoprecipitation showed that, compared to endophilin I/II, the interaction between endophilin III and dynamin I was significantly increased. Similar results were obtained from flow cytometry. Furthermore, endophilin III had a higher overlap coefficient with dynamin I in co-transfected 293T cells. Conclusion Endophilin isoforms have distinct characteristics in interactions with NCF and dynamin I. Endophilin III binding to NCF is Ca 2＋ -independent, implying that it plays a different role in clathrin-mediated endocytosis.
基金the Science and Technology Development Program of Hunan Province,No.2008FJ3195
文摘The current study examined a rat model of vascular dementia. The model rats exhibited obvious morphological and ultrastructural changes in neurons in the brain, and significantly reduced dynamin 1 expression in hippocampal CA1 region along with decreased learning and memory performance. Following atorvastatin treatment, the morphology and ultrastructure of cells in the model rat brain were significantly improved, dynamin 1 expression in hippocampal CA1 region was significantly enhanced, and learning and memory ability was significantly improved. The results demonstrated that impaired learning and memory abilities in vascular dementia model rats were closely correlated with decreased dynamin 1 expression. These findings indicate that atorvastatin can protect model rats against cognitive impairment by increasing dynamin 1 expression.
文摘FcαR, the Fc receptor for IgA, is essential for IgA-mediated immune responses. Previous studies have shown that IgA and IgA immune complexes can be rapidly endocytosed by FcαR. However, the underlying mechanism remains unclear. Here, we investigated the endocytic pathway of FcαR in monocytic cell line, U937, that naturally express FcuR and in transfected Chinese hamster ovary （CHO）, COS-7 and Hela cells. By using selective chemical inhibitors of different endocytic pathways, overexpression of dominant-negative mutants of Eps15 and knockdown of clathrin heavy chain （CHC） via RNA interference, we demonstrated that endocytosis of FcaR was through a clathrin-mediated pathway. The endocytosed FcαR went into Rab5- and Rabll-positive endosomes. However, endocytosis of FcaR could not be blocked by a dominant-negative mutant of Rab5. We also demonstrated that endocytosis of FcαR was dynamin-dependent by overexpressing a dominant-negative mutant of dynamin. The potential endocytic motif for FcαR was also examined. Unexpectedly, we found that the entire cytoplasmic domain of FcaR was not required for the endocytic process of FcαR. We conclude that endocytosis of FcaR is clathrin- and dynamin-dependent, but is not regulated by RabS, and the endocytic motif is not located in the cytoplasmic domain of FcαR.
基金supported by the National Natural Science Foundation of China(No.31271432)the National Basic Research Program of China(Nos.2012CB966600 and 2014CB943100)the Specialized Research Fund for the Doctoral Program of Higher Education(No.20130101110116)
文摘Autophagy is a central lysosomal degradation pathway required for maintaining cellular homeostasis and its dysfunction is associated with numerous human diseases. To identify players in autophagy, we tested ~ 1200 chemically induced mutations on the X chromosome in Drosophila fat body clones and discovered that shibire （shi） plays an essential role in starvation-induced autophagy, shi encodes a dynamin protein required for fission of clathrin-coated vesicles from the plasma membrane during endocytosis. We showed that Shi is dispensable for autophagy initiation and autophagosome--lysosome fusion, but required for lysosomal/autolysosomal acidification. We also showed that other endocytic core machinery components like clathrin and AP2 play similar but not identical roles in regulating autophagy and lysosomal function as dynamin. Previous studies suggested that dynamin directly regulates autophagosome formation and autophagic lysosome reformation （ALR） through its excision activity, Here, we provide evidence that dynamin also regulates autophagy indirectly by regulating lysosomal function.
