Autophagy is an important lysosomal degradation pathway that aids in the maintenance of cellular homeostasis by breaking down and recycling intracellular contents. Dysregulation of autophagy is linked to a growing num...Autophagy is an important lysosomal degradation pathway that aids in the maintenance of cellular homeostasis by breaking down and recycling intracellular contents. Dysregulation of autophagy is linked to a growing number of human diseases. The Beclin 1-Vps34 protein-protein interaction network is critical for autophagy regulation and is therefore essential to cellular integrity. Manipulation of autophagy, in particular via modulation of the action of the Beclin I-Vps34 complexes, is considered a promising route to combat autophagy-related diseases. Here we summarize recent findings on the core components and structural architecture of the Beclin 1-Vps34 complexes, and how these findings provide valuable insights into the molecular mechanisms that underlie the multiple functions of these complexes and for devising therapeutic strategies.展开更多
We report in this study the identification of a natural product-like antagonist(1a) of Vps34 as a potent autophagy modulator via structure-based virtual screening. Aurone derivative 1a strongly inhibited Vps34 activit...We report in this study the identification of a natural product-like antagonist(1a) of Vps34 as a potent autophagy modulator via structure-based virtual screening. Aurone derivative 1a strongly inhibited Vps34 activity in cell-free and cell-based assays. Significantly, 1a prevents autophagy in human cells induced either by starvation or by an mT OR inhibitor. In silico modeling and kinetic data revealed that 1a could function as an ATP-competitive inhibitor of Vps34. Moreover, it suppressed autophagy in vivo and without inducing heart or liver damage in mice. 1a could be utilized as a new motif for more selective and efficacious antagonists of Vps34 for the potential treatment of autophagy-related human diseases.展开更多
Vps34(vacuolar protein-sorting 34)plays important role in autophagy and endosomal trafficking.These processes are closely associated protein ubiquitination and degradation.We have hypothesized that Vps34 ubiquitinatio...Vps34(vacuolar protein-sorting 34)plays important role in autophagy and endosomal trafficking.These processes are closely associated protein ubiquitination and degradation.We have hypothesized that Vps34 ubiquitination status would also control its degradation.Here,we report that our results did not support this assumption.In cells transiently transfected with ubiquitin(UB)constructs contained different lysine residues(Ks),Vps34 ubiquitination could occur regardless of the presence of any Ks in UB.However,Vps34 protein levels were not significantly altered in cells transiently transfected with these UB mutants.We further found that Vps34 protein was altered by pharmacological manipulation of E2/E3 activity;yet this effect was not significantly affected by UB overexpression.In vivo experiments revealed that in APP/PS1 mice,an animal model of Alzheimer’s disease(AD),although ubiquitination of Vps34 was significantly reduced,Vps34 protein levels remained unchanged.Vps34 indeed was subjected to proteasomal or lysosomal degradation,as prolonged treatment of proteasomal inhibitor MG132 or lysosomal inhibitor chloroquine elevated Vps34 protein levels.We conclude that unlike most of other proteins,Vps34 ubiquitination is not closely associated with its degradation.展开更多
During their growth and development, animals adapt to tremendous changes in order to survive. These include responses to both environmental and physiological changes and autophagy is one of most important adaptive and...During their growth and development, animals adapt to tremendous changes in order to survive. These include responses to both environmental and physiological changes and autophagy is one of most important adaptive and regulatory mechanisms. Autophagy is defined as an autolytic process to clear damaged cellular organelles and recycle the nutrients via lysosomic degradation. The process of autophagy responds to special conditions such as nutrient withdrawal. Once autophagy is induced,phagophores form and then elongate and curve to form autophagosomes. Autophagosomes then engulf cargo,fuse with endosomes, and finally fuse with lysosomes for maturation. During the initiation process, the ATG1/ULK1(unc-51-like kinase 1) and VPS34(which encodes a class III phosphatidylinositol(Ptd Ins) 3-kinase) complexes are critical in recruitment and assembly of other complexes required for autophagy. The process of autophagy is regulated by autophagy related genes(ATGs). Amino acid and energy starvation mediate autophagy by activating m TORC1(mammalian target of rapamycin) and AMPactivated protein kinase(AMPK). AMPK is the energy status sensor, the core nutrient signaling component and the metabolic kinase of cells. This review mainly focuses on the mechanism of autophagy regulated by nutrient signaling especially for the two important complexes,ULK1 and VPS34.展开更多
Autophagy is a conserved lysosomal-dependent catabolic process that maintains the cellular homeostasis by recycling misfolded proteins and damaged organelles. It involves a series of ordered events (initiation, nuclea...Autophagy is a conserved lysosomal-dependent catabolic process that maintains the cellular homeostasis by recycling misfolded proteins and damaged organelles. It involves a series of ordered events (initiation, nucleation, elongation, lysosomal fusion and degradation) that are tightly regulated/controlled by diverse cell signals and stress. It is like a double-edged sword that can play either a protective or destructive role in cancer, by pro-survival or apoptotic cues. Recently, modulating autophagy by pharmacological agents has become an attractive strategy to treat cancer. Currently, a number of small molecules that inhibit autophagy initiation (e.g., ULK kinase inhibitors), nucleation (e.g., Vps34 inhibitors), elongation (e.g., ATG4 inhibitors) and lysosome fusion (e.g., chloroquine, hydroxyl chloroquine,etc.) are reported in pre-clinical and clinical study. Also a number of small molecules reported to induce autophagy by targeting mammalian target of rapamycin (e.g., rapamycin analogs) or adenosine 5'-monophosphate-activated protein kinase (e.g., sulforaphane). The study results suggest that many potential "druggable" targets exist in the autophagy pathway that could be harnessed for developing new cancer therapeutics. In this review, we discuss the reported autophagy modulators (inhibitors and inducers), their molecular mode of action and their applications in cancer therapy.展开更多
文摘Autophagy is an important lysosomal degradation pathway that aids in the maintenance of cellular homeostasis by breaking down and recycling intracellular contents. Dysregulation of autophagy is linked to a growing number of human diseases. The Beclin 1-Vps34 protein-protein interaction network is critical for autophagy regulation and is therefore essential to cellular integrity. Manipulation of autophagy, in particular via modulation of the action of the Beclin I-Vps34 complexes, is considered a promising route to combat autophagy-related diseases. Here we summarize recent findings on the core components and structural architecture of the Beclin 1-Vps34 complexes, and how these findings provide valuable insights into the molecular mechanisms that underlie the multiple functions of these complexes and for devising therapeutic strategies.
基金supported by Hong Kong Baptist University (FRG2/ 16–17/007, FRG2/17–18/003, China)the Health and Medical Research Fund (HMRF/14150561, China)+9 种基金the Research Grants Council (HKBU/12301115, China)the National Natural Science Foundation of China (21575121 and 21775131, China)the Hong Kong Baptist University Century Club Sponsorship Scheme 2018 (China)the Interdisciplinary Research Matching Scheme (RC-IRMS/16–17/03, China)Interdisciplinary Research Clusters Matching Scheme (RC-IRCs/17–18/03, China)Innovation and Technology Fund (ITS/260/16FX, China), Matching Proof of Concept Fund (MPCF-001–2017/18, China)Collaborative Research Fund (C5026-16G, China), SKLEBA and HKBU Strategic Development Fund (SKLP_1718_P04, China)the Science and Technology Development Fund, Macao SAR (0072/ 2018/A2, China)the University of Macao (MYRG2016-00151ICMS-QRCM and MYRG2018-00187-ICMS, China)a Discovery Project Grant (DP160101682, Australia) from the Australian Research Council
文摘We report in this study the identification of a natural product-like antagonist(1a) of Vps34 as a potent autophagy modulator via structure-based virtual screening. Aurone derivative 1a strongly inhibited Vps34 activity in cell-free and cell-based assays. Significantly, 1a prevents autophagy in human cells induced either by starvation or by an mT OR inhibitor. In silico modeling and kinetic data revealed that 1a could function as an ATP-competitive inhibitor of Vps34. Moreover, it suppressed autophagy in vivo and without inducing heart or liver damage in mice. 1a could be utilized as a new motif for more selective and efficacious antagonists of Vps34 for the potential treatment of autophagy-related human diseases.
基金This work was supported by The National Natural Science Foudantion of China grant(81220108010).
文摘Vps34(vacuolar protein-sorting 34)plays important role in autophagy and endosomal trafficking.These processes are closely associated protein ubiquitination and degradation.We have hypothesized that Vps34 ubiquitination status would also control its degradation.Here,we report that our results did not support this assumption.In cells transiently transfected with ubiquitin(UB)constructs contained different lysine residues(Ks),Vps34 ubiquitination could occur regardless of the presence of any Ks in UB.However,Vps34 protein levels were not significantly altered in cells transiently transfected with these UB mutants.We further found that Vps34 protein was altered by pharmacological manipulation of E2/E3 activity;yet this effect was not significantly affected by UB overexpression.In vivo experiments revealed that in APP/PS1 mice,an animal model of Alzheimer’s disease(AD),although ubiquitination of Vps34 was significantly reduced,Vps34 protein levels remained unchanged.Vps34 indeed was subjected to proteasomal or lysosomal degradation,as prolonged treatment of proteasomal inhibitor MG132 or lysosomal inhibitor chloroquine elevated Vps34 protein levels.We conclude that unlike most of other proteins,Vps34 ubiquitination is not closely associated with its degradation.
基金financial support from the China Scholarship Council, the National Basic Research Program of China (2013CB117301)the National Natural Science Foundation of China (31272448, 31472101, 31420103908, and 31528018)+3 种基金the 111 Project (B16044)Beijing Nova Program (xx2013055)Education Foundation of China Agricultural University "Dabeinong Education Fund" (1041-2415001)National Department Public Benefit Research Foundation (201403047) are gratefully acknowledged
文摘During their growth and development, animals adapt to tremendous changes in order to survive. These include responses to both environmental and physiological changes and autophagy is one of most important adaptive and regulatory mechanisms. Autophagy is defined as an autolytic process to clear damaged cellular organelles and recycle the nutrients via lysosomic degradation. The process of autophagy responds to special conditions such as nutrient withdrawal. Once autophagy is induced,phagophores form and then elongate and curve to form autophagosomes. Autophagosomes then engulf cargo,fuse with endosomes, and finally fuse with lysosomes for maturation. During the initiation process, the ATG1/ULK1(unc-51-like kinase 1) and VPS34(which encodes a class III phosphatidylinositol(Ptd Ins) 3-kinase) complexes are critical in recruitment and assembly of other complexes required for autophagy. The process of autophagy is regulated by autophagy related genes(ATGs). Amino acid and energy starvation mediate autophagy by activating m TORC1(mammalian target of rapamycin) and AMPactivated protein kinase(AMPK). AMPK is the energy status sensor, the core nutrient signaling component and the metabolic kinase of cells. This review mainly focuses on the mechanism of autophagy regulated by nutrient signaling especially for the two important complexes,ULK1 and VPS34.
文摘Autophagy is a conserved lysosomal-dependent catabolic process that maintains the cellular homeostasis by recycling misfolded proteins and damaged organelles. It involves a series of ordered events (initiation, nucleation, elongation, lysosomal fusion and degradation) that are tightly regulated/controlled by diverse cell signals and stress. It is like a double-edged sword that can play either a protective or destructive role in cancer, by pro-survival or apoptotic cues. Recently, modulating autophagy by pharmacological agents has become an attractive strategy to treat cancer. Currently, a number of small molecules that inhibit autophagy initiation (e.g., ULK kinase inhibitors), nucleation (e.g., Vps34 inhibitors), elongation (e.g., ATG4 inhibitors) and lysosome fusion (e.g., chloroquine, hydroxyl chloroquine,etc.) are reported in pre-clinical and clinical study. Also a number of small molecules reported to induce autophagy by targeting mammalian target of rapamycin (e.g., rapamycin analogs) or adenosine 5'-monophosphate-activated protein kinase (e.g., sulforaphane). The study results suggest that many potential "druggable" targets exist in the autophagy pathway that could be harnessed for developing new cancer therapeutics. In this review, we discuss the reported autophagy modulators (inhibitors and inducers), their molecular mode of action and their applications in cancer therapy.
