Beclin 1, a protein essential for autophagy, binds to hVps34/Class III phosphatidylinositol-3-kinase and UVRAG. Here, we have identified two Beclin 1 associated proteins, Atg14L and Rubicon. Atg14L and UVRAG bind to Beclin 1 in a mutually exclusive manner, whereas Rubicon binds only to a subpopulation of UVRAG complexes; thus, three different Beclin 1 complexes exist. GFP-Atg14L localized to the isolation membrane and autophagosome, as well as to the ER and unknown puncta. Knockout of Atg14L in mouse ES cells caused a defect in autophagosome formation. GFP-Rubicon was localized at the endosome/lysosome. Knockdown of Rubicon caused enhancement of autophagy, especially at the maturation step, as well as enhancement of endocytic trafficking. These data suggest that the Beclin 1-hVps34 complex functions in two different steps of autophagy by altering the subunit composition.
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http://dx.doi.org/10.1038/ncb1846 | DOI Listing |
J Med Chem
January 2025
Chemical Biology Section, Molecular Targets Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702, United States.
Autophagy, a recycling process in eukaryotes, contributes to tumor growth and metastasis by alleviating cellular stress and facilitating survival and chemoresistance. The development of small molecules that selectively inhibit this pathway has proven challenging and is required to determine if autophagy inhibition can be harnessed as an effective therapeutic strategy in cancer. Compound 19 was previously identified as a selective autophagy inhibitor that targets the ATG14L-Beclin1 protein-protein interaction, which regulates the formation, localization, and function of VPS34 Complex I to initiate autophagy.
View Article and Find Full Text PDFNat Commun
August 2024
Laboratory of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan.
Autophagy is a highly conserved process from yeast to mammals in which intracellular materials are engulfed by a double-membrane organelle called autophagosome and degrading materials by fusing with the lysosome. The process of autophagy is regulated by sequential recruitment and function of autophagy-related (Atg) proteins. Genetic hierarchical analyses show that the ULK1 complex comprised of ULK1-FIP200-ATG13-ATG101 translocating from the cytosol to autophagosome formation sites as a most upstream ATG factor; this translocation is critical in autophagy initiation.
View Article and Find Full Text PDFJ Nutr Biochem
September 2024
Department of General Medicine, Qilu Hospital of Shandong University,107 Wenhuaxi Road, 250012, Jinan, Shandong, China; The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Chinese National Health Commission and Chinese Academy of Medical Sciences, The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Qilu Hospital of Shandong University, 107 Wenhuaxi Road, 250012,Jinan,Shandong, China. Electronic address:
Recently, emerging evidence has suggested that obesity become a prevalent health threat worldwide. Reportedly, CTRP9 can ameliorate HFD induced obesity. However, the molecular mechanism underlying the role of CTRP9 in obesity remains elusive.
View Article and Find Full Text PDFBiol Res
May 2024
Department of Veterinary Medicine, Institute of Veterinary Science, College of Veterinary Medicine, Chungnam National University, 99 Daehak-ro, Yusung-gu, Daejeon, 34134, Republic of Korea.
EMBO J
March 2024
Zhejiang Provincial Key Laboratory of Pancreatic Disease, The First Affiliated Hospital, and Institute of Translational Medicine, Zhejiang University School of Medicine, Zhejiang University, 310029, Hangzhou, China.
The Von Hippel-Lindau (VHL) protein, which is frequently mutated in clear-cell renal cell carcinoma (ccRCC), is a master regulator of hypoxia-inducible factor (HIF) that is involved in oxidative stresses. However, whether VHL possesses HIF-independent tumor-suppressing activity remains largely unclear. Here, we demonstrate that VHL suppresses nutrient stress-induced autophagy, and its deficiency in sporadic ccRCC specimens is linked to substantially elevated levels of autophagy and correlates with poorer patient prognosis.
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