title: Residue 146 regulates prolactin receptor folding, basal activity and ligand-responsiveness: potential implications in breast tumorigenesis.
abstract: PRLR(I146L) is the first identified gain-of-function variant of the prolactin receptor (PRLR) that was proposed to be associated with benign breast tumorigenesis. Structural investigations suggested this hydrophobic core position in the extracellular D2 domain to be linked to receptor dimerization. Here, we used a mutational approach to address how the conservative I-to-L substitution induced constitutive activity. Using cell-based assays of different I146-PRLR variants in combination with spectroscopic/nuclear magnetic resonance analyses we found that chemical manipulation of position 146 profoundly altered folding, PRL-responsiveness, and ligand-independent activity of the receptor in a mutation-specific manner. Together, these data further add to the critical role of position 146, showing it to also be crucial to structural integrity thereby imposing on the biological PRLR properties. When stably introduced in MCF-7 (luminal) and MDA-MB231 (mesenchymal) breast cancer cells, the most potent of the PRL-insensitive mutants (PRLR(I146D)) had minimal impact on cell proliferation and cell differentiation status.
authors.affiliation: Inserm U1151, Institut Necker Enfants Malades (INEM), Equipe Physiopathologie des Hormones PRL/GH, Paris, France; Sorbonne Paris Cité, Université Paris Descartes, Paris, France.
authors.forename: Chi
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Inserm U1151, Institut Necker Enfants Malades (INEM), Equipe Physiopathologie des Hormones PRL/GH, Paris, France; Sorbonne Paris Cité, Université Paris Descartes, Paris, France.
authors.forename: Ibtissem
authors.initials: I
authors.lastname: Cherifi
authors.affiliation: Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Mads
authors.initials: M
authors.lastname: Nygaard
authors.affiliation: Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Gitte W
authors.initials: GW
authors.lastname: Haxholm
authors.affiliation: Inserm U1151, Institut Necker Enfants Malades (INEM), Equipe Physiopathologie des Hormones PRL/GH, Paris, France; Sorbonne Paris Cité, Université Paris Descartes, Paris, France.
authors.forename: Roman L
authors.initials: RL
authors.lastname: Bogorad
authors.affiliation: Inserm U1151, Institut Necker Enfants Malades (INEM), Equipe Physiopathologie des Hormones PRL/GH, Paris, France; Sorbonne Paris Cité, Université Paris Descartes, Paris, France.
authors.forename: Marie
authors.initials: M
authors.lastname: Bernadet
authors.affiliation: Institut Pasteur, Plateforme de Biophysique des Macromolécules et de leurs Interactions, Département de Biologie Structurale et Chimie, F-75015 Paris, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: England
authors.affiliation: Sorbonne Paris Cité, Université Paris Descartes, Paris, France; Laboratoire de Cristallographie et RMN Biologiques CNRS, UMR 8015 Paris, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Broutin
authors.affiliation: Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Birthe B
authors.initials: BB
authors.lastname: Kragelund
authors.affiliation: Inserm U1151, Institut Necker Enfants Malades (INEM), Equipe Physiopathologie des Hormones PRL/GH, Paris, France; Sorbonne Paris Cité, Université Paris Descartes, Paris, France.
authors.forename: Jacques-Emmanuel
authors.initials: JE
authors.lastname: Guidotti
authors.affiliation: Inserm U1151, Institut Necker Enfants Malades (INEM), Equipe Physiopathologie des Hormones PRL/GH, Paris, France; Sorbonne Paris Cité, Université Paris Descartes, Paris, France. Electronic address: vincent.goffin@inserm.fr.
authors.forename: Vincent
authors.initials: V
authors.lastname: Goffin
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D001943:Breast Neoplasms / Q000378:metabolism*; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002942:Circular Dichroism; D004252:DNA Mutational Analysis / Q000379:methods*; D005260:Female; D057809:HEK293 Cells; D006801:Humans; D061986:MCF-7 Cells; D051379:Mice; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D011487:Protein Conformation; D017510:Protein Folding; D011981:Receptors, Prolactin / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism
chemical_list: D011981:Receptors, Prolactin
keywords: Breast cancer; Ile146; MAPK; Proliferation; STAT5; Structure