title: GHR/PRLR Heteromultimer Is Composed of GHR Homodimers and PRLR Homodimers.
abstract: GH receptor (GHR) and prolactin (PRL) receptor (PRLR) are homologous transmembrane cytokine receptors. Each prehomodimerizes and ligand binding activates Janus Kinase 2 (JAK2)-signal transducer and activator of transcription (STAT) signaling pathways by inducing conformational changes within receptor homodimers. In humans, GHR is activated by GH, whereas PRLR is activated by both GH and PRL. We previously devised a split luciferase complementation assay, in which 1 receptor is fused to an N-terminal luciferase (Nluc) fragment, and the other receptor is fused to a C-terminal luciferase (Cluc) fragment. When receptors approximate, luciferase activity (complementation) results. Using this assay, we reported ligand-independent GHR-GHR complementation and GH-induced complementation changes characterized by acute augmentation above basal signal, consistent with induction of conformational changes that bring GHR cytoplasmic tails closer. We also demonstrated association between GHR and PRLR in T47D human breast cancer cells by coimmunoprecipitation, suggesting that, in addition to forming homodimers, these receptors form hetero-assemblages with functional consequences. We now extend these analyses to examine basal and ligand-induced complementation of coexpressed PRLR-Nluc and PRLR-Cluc chimeras and coexpressed GHR-Nluc and PRLR-Cluc chimeras. We find that PRLR-PRLR and GHR-PRLR form specifically interacting ligand-independent assemblages and that either GH or PRL augments PRLR-PRLR complementation, much like the GH-induced changes in GHR-GHR dimers. However, in contrast to the complementation patterns for GHR-GHR or PRLR-PRLR homomers, both GH and PRL caused decline in luciferase activity for GHR-PRLR heteromers. These and other data suggest that GHR and PRLR associate in complexes comprised of GHR-GHR/PRLR-PRLR heteromers consisting of GHR homodimers and PRLR homodimers, rather than GHR-PRLR heterodimers.
authors.affiliation: Department of Medicine (Y.L., Y.Z., J.J., S.J.F.), Division of Endocrinology, Diabetes, and Metabolism; Department of Radiology (K.R.Z.); and Department of Cell, Developmental, and Integrative Biology (S.J.F.), University of Alabama at Birmingham, Birmingham, Alabama 35294; Cancer Science Institute of Singapore and Department of Pharmacology (P.E.L.), National University of Singapore, Singapore 119077; Department of Radiology (R.P.), Stanford University School of Medicine, Palo Alto, California 94304; Department of Biological Sciences (J.F.L., W.Y.C.), Clemson University, Clemson, South Carolina 29634; and Endocrinology Section (S.J.F.), Medical Service, Veterans Affairs Medical Center, Birmingham, Alabama 35233.
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Medicine (Y.L., Y.Z., J.J., S.J.F.), Division of Endocrinology, Diabetes, and Metabolism; Department of Radiology (K.R.Z.); and Department of Cell, Developmental, and Integrative Biology (S.J.F.), University of Alabama at Birmingham, Birmingham, Alabama 35294; Cancer Science Institute of Singapore and Department of Pharmacology (P.E.L.), National University of Singapore, Singapore 119077; Department of Radiology (R.P.), Stanford University School of Medicine, Palo Alto, California 94304; Department of Biological Sciences (J.F.L., W.Y.C.), Clemson University, Clemson, South Carolina 29634; and Endocrinology Section (S.J.F.), Medical Service, Veterans Affairs Medical Center, Birmingham, Alabama 35233.
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Medicine (Y.L., Y.Z., J.J., S.J.F.), Division of Endocrinology, Diabetes, and Metabolism; Department of Radiology (K.R.Z.); and Department of Cell, Developmental, and Integrative Biology (S.J.F.), University of Alabama at Birmingham, Birmingham, Alabama 35294; Cancer Science Institute of Singapore and Department of Pharmacology (P.E.L.), National University of Singapore, Singapore 119077; Department of Radiology (R.P.), Stanford University School of Medicine, Palo Alto, California 94304; Department of Biological Sciences (J.F.L., W.Y.C.), Clemson University, Clemson, South Carolina 29634; and Endocrinology Section (S.J.F.), Medical Service, Veterans Affairs Medical Center, Birmingham, Alabama 35233.
authors.forename: Jing
authors.initials: J
authors.lastname: Jiang
authors.affiliation: Department of Medicine (Y.L., Y.Z., J.J., S.J.F.), Division of Endocrinology, Diabetes, and Metabolism; Department of Radiology (K.R.Z.); and Department of Cell, Developmental, and Integrative Biology (S.J.F.), University of Alabama at Birmingham, Birmingham, Alabama 35294; Cancer Science Institute of Singapore and Department of Pharmacology (P.E.L.), National University of Singapore, Singapore 119077; Department of Radiology (R.P.), Stanford University School of Medicine, Palo Alto, California 94304; Department of Biological Sciences (J.F.L., W.Y.C.), Clemson University, Clemson, South Carolina 29634; and Endocrinology Section (S.J.F.), Medical Service, Veterans Affairs Medical Center, Birmingham, Alabama 35233.
authors.forename: Peter E
authors.initials: PE
authors.lastname: Lobie
authors.affiliation: Department of Medicine (Y.L., Y.Z., J.J., S.J.F.), Division of Endocrinology, Diabetes, and Metabolism; Department of Radiology (K.R.Z.); and Department of Cell, Developmental, and Integrative Biology (S.J.F.), University of Alabama at Birmingham, Birmingham, Alabama 35294; Cancer Science Institute of Singapore and Department of Pharmacology (P.E.L.), National University of Singapore, Singapore 119077; Department of Radiology (R.P.), Stanford University School of Medicine, Palo Alto, California 94304; Department of Biological Sciences (J.F.L., W.Y.C.), Clemson University, Clemson, South Carolina 29634; and Endocrinology Section (S.J.F.), Medical Service, Veterans Affairs Medical Center, Birmingham, Alabama 35233.
authors.forename: Ramasamy
authors.initials: R
authors.lastname: Paulmurugan
authors.affiliation: Department of Medicine (Y.L., Y.Z., J.J., S.J.F.), Division of Endocrinology, Diabetes, and Metabolism; Department of Radiology (K.R.Z.); and Department of Cell, Developmental, and Integrative Biology (S.J.F.), University of Alabama at Birmingham, Birmingham, Alabama 35294; Cancer Science Institute of Singapore and Department of Pharmacology (P.E.L.), National University of Singapore, Singapore 119077; Department of Radiology (R.P.), Stanford University School of Medicine, Palo Alto, California 94304; Department of Biological Sciences (J.F.L., W.Y.C.), Clemson University, Clemson, South Carolina 29634; and Endocrinology Section (S.J.F.), Medical Service, Veterans Affairs Medical Center, Birmingham, Alabama 35233.
authors.forename: John F
authors.initials: JF
authors.lastname: Langenheim
authors.affiliation: Department of Medicine (Y.L., Y.Z., J.J., S.J.F.), Division of Endocrinology, Diabetes, and Metabolism; Department of Radiology (K.R.Z.); and Department of Cell, Developmental, and Integrative Biology (S.J.F.), University of Alabama at Birmingham, Birmingham, Alabama 35294; Cancer Science Institute of Singapore and Department of Pharmacology (P.E.L.), National University of Singapore, Singapore 119077; Department of Radiology (R.P.), Stanford University School of Medicine, Palo Alto, California 94304; Department of Biological Sciences (J.F.L., W.Y.C.), Clemson University, Clemson, South Carolina 29634; and Endocrinology Section (S.J.F.), Medical Service, Veterans Affairs Medical Center, Birmingham, Alabama 35233.
authors.forename: Wen Y
authors.initials: WY
authors.lastname: Chen
authors.affiliation: Department of Medicine (Y.L., Y.Z., J.J., S.J.F.), Division of Endocrinology, Diabetes, and Metabolism; Department of Radiology (K.R.Z.); and Department of Cell, Developmental, and Integrative Biology (S.J.F.), University of Alabama at Birmingham, Birmingham, Alabama 35294; Cancer Science Institute of Singapore and Department of Pharmacology (P.E.L.), National University of Singapore, Singapore 119077; Department of Radiology (R.P.), Stanford University School of Medicine, Palo Alto, California 94304; Department of Biological Sciences (J.F.L., W.Y.C.), Clemson University, Clemson, South Carolina 29634; and Endocrinology Section (S.J.F.), Medical Service, Veterans Affairs Medical Center, Birmingham, Alabama 35233.
authors.forename: Kurt R
authors.initials: KR
authors.lastname: Zinn
authors.affiliation: Department of Medicine (Y.L., Y.Z., J.J., S.J.F.), Division of Endocrinology, Diabetes, and Metabolism; Department of Radiology (K.R.Z.); and Department of Cell, Developmental, and Integrative Biology (S.J.F.), University of Alabama at Birmingham, Birmingham, Alabama 35294; Cancer Science Institute of Singapore and Department of Pharmacology (P.E.L.), National University of Singapore, Singapore 119077; Department of Radiology (R.P.), Stanford University School of Medicine, Palo Alto, California 94304; Department of Biological Sciences (J.F.L., W.Y.C.), Clemson University, Clemson, South Carolina 29634; and Endocrinology Section (S.J.F.), Medical Service, Veterans Affairs Medical Center, Birmingham, Alabama 35233.
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Frank
mesh_terms: D001943:Breast Neoplasms / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D045744:Cell Line, Tumor; D005260:Female; D013006:Growth Hormone / Q000378:metabolism; D006801:Humans; D047468:Immunoprecipitation / Q000379:methods; D053614:Janus Kinase 2 / Q000378:metabolism; D008024:Ligands; D008156:Luciferases / Q000378:metabolism; D011485:Protein Binding; D055503:Protein Multimerization / Q000502:physiology*; D011981:Receptors, Prolactin / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology
chemical_list: D002352:Carrier Proteins; D008024:Ligands; D011981:Receptors, Prolactin; D013006:Growth Hormone; D008156:Luciferases; C507924:JAK2 protein, human; D053614:Janus Kinase 2; C051815:somatotropin-binding protein