| Autor: |
Heras-Martínez GL; Instituto Biofisika (CSIC, UPV/EHU), 48490, Leioa, Spain.; Cell Biophysics Laboratory, Ikerbasque Basque Foundation for Science, Instituto Biofisika (CSIC, UPV/EHU) & Research Centre for Experimental Marine Biology and Biotechnology (PiE), University of the Basque Country (UPV/EHU), Leioa, 48940, Spain., Calleja V; Protein Phosphorylation Laboratory, The Francis Crick Institute, 1 Midland Road, NW1 1AT, London, UK., Bailly R; Institute of Chemistry & Biology of Membranes & Nanoobjects (UMR 5248 CBMN) CNRS - Université de Bordeaux - Bordeaux INP All. Geoffroy Saint-Hilaire, 33600, Pessac, France., Dessolin J; Institute of Chemistry & Biology of Membranes & Nanoobjects (UMR 5248 CBMN) CNRS - Université de Bordeaux - Bordeaux INP All. Geoffroy Saint-Hilaire, 33600, Pessac, France., Larijani B; Cell Biophysics Laboratory, Ikerbasque Basque Foundation for Science, Instituto Biofisika (CSIC, UPV/EHU) & Research Centre for Experimental Marine Biology and Biotechnology (PiE), University of the Basque Country (UPV/EHU), Leioa, 48940, Spain. banafshe.larijani@ikerbasque.org.; Centre for Therapeutic Innovation (CTI-Bath); Cell Biophysics Laboratory Department of Pharmacy & Pharmacology University, Bath, Claverton Down, Bath, BA2 7AY, United Kingdom. banafshe.larijani@ikerbasque.org., Requejo-Isidro J; Instituto Biofisika (CSIC, UPV/EHU), 48490, Leioa, Spain. jose.requejo@csic.es.; Centro Nacional de Biotecnología (CSIC), Darwin, 3, E28049, Madrid, Spain. jose.requejo@csic.es.; Unidad de Nanobiotecnología, CNB-CSIC-IMDEA Nanociencia Associated Unit, 28049, Madrid, Spain. jose.requejo@csic.es. |
| Abstrakt: |
3'-Phosphoinositide-dependent-Kinase-1 (PDK1) is a master regulator whereby its PI3-kinase-dependent dysregulation in human pathologies is well documented. Understanding the direct role for PtdIns(3,4,5)P 3 and other anionic phospholipids in the regulation of PDK1 conformational dynamics and its downstream activation remains incomplete. Using advanced quantitative-time-resolved imaging (Fluorescence Lifetime Imaging and Fluorescence Correlation Spectroscopy) and molecular modelling, we show an interplay of antagonistic binding effects of PtdIns(3,4,5)P 3 and other anionic phospholipids, regulating activated PDK1 homodimers. We demonstrate that phosphatidylserine maintains PDK1 in an inactive conformation. The dysregulation of the PI3K pathway affects the spatio-temporal and conformational dynamics of PDK1 and the activation of its downstream substrates. We have established a new anionic-phospholipid-dependent model for PDK1 regulation, depicting the conformational dynamics of multiple homodimer states. We show that the dysregulation of the PI3K pathway perturbs equilibrium between the PDK1 homodimer conformations. Our findings provide a role for the PtdSer binding site and its previously unrewarding role in PDK1 downregulation, suggesting a possible therapeutic strategy where the constitutively active dimer conformer of PDK1 may be rendered inactive by small molecules that drive it to its PtdSer-bound conformer. |
