Endothelial PKA activity regulates angiogenesis by limiting autophagy through phosphorylation of ATG16L1
- VIB, Belgium
- INSERM UMR-970, France
- Max Delbrück Center for Molecular Medicine, Germany
- Luxembourg Institute of Health, Luxembourg
Abstract
The cAMP-dependent protein kinase A (PKA) regulates various cellular functions in health and disease. In endothelial cells PKA activity promotes vessel maturation and limits tip cell formation. Here, we used a chemical genetic screen to identify endothelial-specific direct substrates of PKA in human umbilical vein endothelial cells (HUVEC) that may mediate these effects. Amongst several candidates, we identified ATG16L1, a regulator of autophagy, as novel target of PKA. Biochemical validation, mass spectrometry and peptide spot arrays revealed that PKA phosphorylates ATG16L1α at Ser268 and ATG16L1β at Ser269, driving phosphorylation-dependent degradation of ATG16L1 protein. Reducing PKA activity increased ATG16L1 protein levels and endothelial autophagy. Mouse in vivo genetics and pharmacological experiments demonstrated that autophagy inhibition partially rescues vascular hypersprouting caused by PKA deficiency. Together these results indicate that endothelial PKA activity mediates a critical switch from active sprouting to quiescence in part through phosphorylation of ATG16L1, which in turn reduces endothelial autophagy.
Data availability
The mass spectrometry proteomics data have been deposited to the ProteomeXchange Consortium via the PRIDE partner repository with the dataset identifier PXD012975. All data generated or analysed during this study are included in the manuscript and supporting files. Source data files have been provided for figures 3, 4 and 5.
Article and author information
Author details
Anne-Clemence Vion
Funding
Fonds vor Wetenschappelijk Onderzoek (G.0742.15N)
- Holger Gerhardt
Else-Kroener Stiftung (2014_A26)
- Pavel Nedvetsky
- Holger Gerhardt
European Research Council (311719 REshape)
- Holger Gerhardt
Deutsche Forschungsgemeinschaft (DFG KL1415/7-1)
- Enno Klussmann
Deutsche Forschungsgemeinschaft (394046635 - SFB 1365)
- Enno Klussmann
Bundes Ministerium für Bildung und Forschung (16GW0179K)
- Enno Klussmann
VIB (Tech Watch Q3 2015)
- Pavel Nedvetsky
- Holger Gerhardt
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: All animal experimental procedures were approved by the Institutional Animal Care and Research Advisory Committee of the University of Leuven (application P249/2014) and performed according to the European guidelines.
Copyright
© 2019, Zhao et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
Download links
Further reading
-
- Biochemistry and Chemical Biology
- Microbiology and Infectious Disease
Glutamine synthetases (GS) are central enzymes essential for the nitrogen metabolism across all domains of life. Consequently, they have been extensively studied for more than half a century. Based on the ATP-dependent ammonium assimilation generating glutamine, GS expression and activity are strictly regulated in all organisms. In the methanogenic archaeon Methanosarcina mazei, it has been shown that the metabolite 2-oxoglutarate (2-OG) directly induces the GS activity. Besides, modulation of the activity by interaction with small proteins (GlnK1 and sP26) has been reported. Here, we show that the strong activation of M. mazei GS (GlnA1) by 2-OG is based on the 2-OG dependent dodecamer assembly of GlnA1 by using mass photometry (MP) and single particle cryo-electron microscopy (cryo-EM) analysis of purified strep-tagged GlnA1. The dodecamer assembly from dimers occurred without any detectable intermediate oligomeric state and was not affected in the presence of GlnK1. The 2.39 Å cryo-EM structure of the dodecameric complex in the presence of 12.5 mM 2-OG demonstrated that 2-OG is binding between two monomers. Thereby, 2-OG appears to induce the dodecameric assembly in a cooperative way. Furthermore, the active site is primed by an allosteric interaction cascade caused by 2-OG-binding towards an adaption of an open active state conformation. In the presence of additional glutamine, strong feedback inhibition of GS activity was observed. Since glutamine dependent disassembly of the dodecamer was excluded by MP, feedback inhibition most likely relies on the binding of glutamine to the catalytic site. Based on our findings, we propose that under nitrogen limitation the induction of M. mazei GS into a catalytically active dodecamer is not affected by GlnK1 and crucially depends on the presence of 2-OG.
