ABSTRACT
The Beclin1-VPS34 complex is recognized as a central node in regulating autophagy via interacting with diverse molecules such as ATG14L for autophagy initiation and UVRAG for autophagosome maturation. However, the underlying molecular mechanism that coordinates the timely activation of VPS34 complex is poorly understood. Here, we identify that PAQR3 governs the preferential formation and activation of ATG14L-linked VPS34 complex for autophagy initiation via two levels of regulation. Firstly, PAQR3 functions as a scaffold protein that facilitates the formation of ATG14L- but not UVRAG-linked VPS34 complex, leading to elevated capacity of PI(3)P generation ahead of starvation signals. Secondly, AMPK phosphorylates PAQR3 at threonine 32 and switches on PI(3)P production to initiate autophagosome formation swiftly after glucose starvation. Deletion of PAQR3 leads to reduction of exercise-induced autophagy in mice, accompanied by a certain degree of disaggregation of ATG14L-associated VPS34 complex. Together, this study uncovers that PAQR3 can not only enhance the capacity of pro-autophagy class III PI3K due to its scaffold function, but also integrate AMPK signal to activation of ATG14L-linked VPS34 complex upon glucose starvation.
Subject(s)
AMP-Activated Protein Kinases/metabolism , Autophagy/physiology , Class III Phosphatidylinositol 3-Kinases/metabolism , Intracellular Signaling Peptides and Proteins/metabolism , Vesicular Transport Proteins/metabolism , Animals , Apoptosis Regulatory Proteins/metabolism , Autophagy-Related Proteins , Beclin-1 , Glucose/deficiency , HEK293 Cells , HeLa Cells , Humans , Intracellular Signaling Peptides and Proteins/genetics , Liver/metabolism , Male , Membrane Proteins , Mice, Knockout , Muscle, Skeletal/metabolism , Running/physiology , Signal TransductionABSTRACT
Calixarenes are reportedly excellent activators that can remarkably improve the transport efficiencies of cell penetrating peptides. We employed eight calixarenes to systematically study the influence of structure on activation efficiency, which revealed that the scaffold, head group, and alkyl chain are all significant factors for activation efficiency by affecting affinities with the peptide and membrane.
Subject(s)
Calixarenes/pharmacology , Peptides/metabolism , Biological Transport/drug effects , Calixarenes/chemistry , Drug Evaluation, Preclinical , Humans , Molecular StructureABSTRACT
The interaction of DNA and the binary complex formed between Ce(IV) and morin was studied. With the maximum scattering peak located at 320 nm, the enhanced RLS was proportional to the concentration of ctDNA in the range 0-25 microg x mL(-1) and the detection limit (3sigma) of 0.3 microg x mL(-1) was obtained. Under the optimized conditions, four synthetic samples were determined with recoveries in the range 93.7%-108.4%. The proposed method is particularly attractive for its high selectivity for ctDNA in the presence of hsDNA by using certain sensitive spectrofluorometer since the intensity of RLS for hsDNA is far weaker than that for ctDNA.