title: Association with coregulators is the major determinant governing peroxisome proliferator-activated receptor mobility in living cells.
abstract: The nucleus is an extremely dynamic compartment, and protein mobility represents a key factor in transcriptional regulation. We showed in a previous study that the diffusion of peroxisome proliferator-activated receptors (PPARs), a family of nuclear receptors regulating major cellular and metabolic functions, is modulated by ligand binding. In this study, we combine fluorescence correlation spectroscopy, dual color fluorescence cross-correlation microscopy, and fluorescence resonance energy transfer to dissect the molecular mechanisms controlling PPAR mobility and transcriptional activity in living cells. First, we bring new evidence that in vivo a high percentage of PPARs and retinoid X receptors is associated even in the absence of ligand. Second, we demonstrate that coregulator recruitment (and not DNA binding) plays a crucial role in receptor mobility, suggesting that transcriptional complexes are formed prior to promoter binding. In addition, association with coactivators in the absence of a ligand in living cells, both through the N-terminal AB domain and the AF-2 function of the ligand binding domain, provides a molecular basis to explain PPAR constitutive activity.
authors.affiliation: Laboratory of Biomolecular Dynamics, Katholieke Universiteit, Leuven B-3001, Belgium.
authors.forename: Cicerone
authors.initials: C
authors.lastname: Tudor
authors.affiliation: Center for Integrative Genomics, National Research Center "Frontiers in Genetics," University of Lausanne, Lausanne CH-1015, Switzerland, and.
authors.forename: Jérôme N
authors.initials: JN
authors.lastname: Feige
authors.affiliation: Zydus Research Centre, Ahmedabad 382210, India.
authors.forename: Harikishore
authors.initials: H
authors.lastname: Pingali
authors.affiliation: Zydus Research Centre, Ahmedabad 382210, India.
authors.forename: Vidya Bhushan
authors.initials: VB
authors.lastname: Lohray
authors.affiliation: Center for Integrative Genomics, National Research Center "Frontiers in Genetics," University of Lausanne, Lausanne CH-1015, Switzerland, and.
authors.forename: Walter
authors.initials: W
authors.lastname: Wahli
authors.affiliation: Center for Integrative Genomics, National Research Center "Frontiers in Genetics," University of Lausanne, Lausanne CH-1015, Switzerland, and.
authors.forename: Béatrice
authors.initials: B
authors.lastname: Desvergne
authors.affiliation: Laboratory of Biomolecular Dynamics, Katholieke Universiteit, Leuven B-3001, Belgium. Electronic address: yves.engelborghs@fys.kuleuven.be.
authors.forename: Yves
authors.initials: Y
authors.lastname: Engelborghs
authors.affiliation: Center for Integrative Genomics, National Research Center "Frontiers in Genetics," University of Lausanne, Lausanne CH-1015, Switzerland, and. Electronic address: laurent.gelman@fmi.ch.
authors.forename: Laurent
authors.initials: L
authors.lastname: Gelman
mesh_terms: D000818:Animals; D031541:Fluorescence Resonance Energy Transfer; D006367:HeLa Cells; D006801:Humans; D008024:Ligands; D009687:Nuclear Proteins / Q000378:metabolism; D047492:Peroxisome Proliferator-Activated Receptors / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D047488:Retinoid X Receptors / Q000378:metabolism*
chemical_list: D008024:Ligands; D009687:Nuclear Proteins; D047492:Peroxisome Proliferator-Activated Receptors; D047488:Retinoid X Receptors