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Zhang C, Nygaard M, Haxholm GW, Boutillon F, Bernadet M, Hoos S, England P, Broutin I, Kragelund BB, Goffin V. A Residue Quartet in the Extracellular Domain of the Prolactin Receptor Selectively Controls Mitogen-activated Protein Kinase Signaling. J Biol Chem 2015; 290:11890-904. [PMID: 25784554 DOI: 10.1074/jbc.m115.639096] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Indexed: 11/06/2022] Open
Abstract
Cytokine receptors elicit several signaling pathways, but it is poorly understood how they select and discriminate between them. We have scrutinized the prolactin receptor as an archetype model of homodimeric cytokine receptors to address the role of the extracellular membrane proximal domain in signal transfer and pathway selection. Structure-guided manipulation of residues involved in the receptor dimerization interface identified one residue (position 170) that in cell-based assays profoundly altered pathway selectivity and species-specific bio-characteristics. Subsequent in vitro spectroscopic and nuclear magnetic resonance analyses revealed that this residue was part of a residue quartet responsible for specific local structural changes underlying these effects. This included alteration of a novel aromatic T-stack within the membrane proximal domain, which promoted selective signaling affecting primarily the MAPK (ERK1/2) pathway. Importantly, activation of the MAPK pathway correlated with in vitro stabilities of ternary ligand·receptor complexes, suggesting a threshold mean lifetime of the complex necessary to achieve maximal activation. No such dependence was observed for STAT5 signaling. Thus, this study establishes a residue quartet in the extracellular membrane proximal domain of homodimeric cytokine receptors as a key regulator of intracellular signaling discrimination.
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Affiliation(s)
- Chi Zhang
- From the Inserm, U1151, Institut Necker Enfants Malades, Equipe Physiopathologie des Hormones PRL/GH, Paris 75014, France, the Université Paris Descartes, Sorbonne Paris Cité, Paris 75006, France
| | - Mads Nygaard
- the Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Gitte W Haxholm
- the Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Florence Boutillon
- From the Inserm, U1151, Institut Necker Enfants Malades, Equipe Physiopathologie des Hormones PRL/GH, Paris 75014, France, the Université Paris Descartes, Sorbonne Paris Cité, Paris 75006, France
| | - Marie Bernadet
- From the Inserm, U1151, Institut Necker Enfants Malades, Equipe Physiopathologie des Hormones PRL/GH, Paris 75014, France, the Université Paris Descartes, Sorbonne Paris Cité, Paris 75006, France
| | - Sylviane Hoos
- the Institut Pasteur, Plateforme de Biophysique des Macromolécules et de leurs Interactions, Département de Biologie Structurale et Chimie, Paris 75015, France, and
| | - Patrick England
- the Institut Pasteur, Plateforme de Biophysique des Macromolécules et de leurs Interactions, Département de Biologie Structurale et Chimie, Paris 75015, France, and
| | - Isabelle Broutin
- the Université Paris Descartes, Sorbonne Paris Cité, Paris 75006, France, Laboratoire de Cristallographie et RMN Biologiques CNRS, UMR 8015, Paris 75006, France
| | - Birthe B Kragelund
- the Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Vincent Goffin
- From the Inserm, U1151, Institut Necker Enfants Malades, Equipe Physiopathologie des Hormones PRL/GH, Paris 75014, France, the Université Paris Descartes, Sorbonne Paris Cité, Paris 75006, France,
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Petridou B. Differences in affinities between the homologous and the heterologous rabbit prolactin-receptor interaction with respect to proliferation and differentiation activities. Gen Comp Endocrinol 2015; 213:118-29. [PMID: 25449135 DOI: 10.1016/j.ygcen.2014.10.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Revised: 09/08/2014] [Accepted: 10/23/2014] [Indexed: 11/23/2022]
Abstract
Interspecies differences in PRL-receptor binding and their relationship with bioactivity deserve investigation since cross-reactivity is relevant to the design of many experiments. We have previously shown that the lower affinity of rabbit prolactin (rbPRL) binding to its homologous receptor is due to its faster and more complete dissociation compared with that of ovine PRL (oPRL). In order to obtain sufficient amounts of rbPRL to study the functional consequences of its low affinity homologous interaction, rbPRL was expressed recombinantly in Escherichia coli (rec rbPRL) as insoluble inclusion bodies, refolded and purified to homogeneity, yielding electrophoretically pure, over 98% monomeric rec rbPRL. Proper renaturation of rec rbPRL was evidenced by comparison of its CD spectra, binding parameters and bioactivity with those determined for the rbPRL. The binding potency of rec rbPRL to its receptor, expressed either endogenously in the mammary gland or recombinantly in mammalian cells is one log unit lower than that to the receptor expressed recombinantly in insect cells. This difference is probably related to differences in cell-dependent receptor densities. The proliferation potency of rbPRL or rec rbPRL was one log unit lower than that of oPRL, consistent with its lower binding affinity, but the differentiation potencies of these PRLs were similar. Thus, the proliferation activity is sensitive to PRL-receptor affinity and dissociation kinetics, whereas the differentiation response is marginally modulated.
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Affiliation(s)
- Barbara Petridou
- UMR 1313 Génétique Animale et Biologie Intégrative, INRA Institut National de la Recherche Agronomique, F-78352 Jouy-en-Josas, France
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Yacobovitz M, Solomon G, Gusakovsky EE, Levavi-Sivan B, Gertler A. Purification and characterization of recombinant pufferfish (Takifugu rubripes) leptin. Gen Comp Endocrinol 2008; 156:83-90. [PMID: 18191858 DOI: 10.1016/j.ygcen.2007.11.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2007] [Revised: 11/11/2007] [Accepted: 11/23/2007] [Indexed: 10/22/2022]
Abstract
Synthetic cDNA encoding pufferfish (Takifugu rubripes) leptin (pfLEP) was prepared according to the published sequence. The pfLEP, transformed into Escherichia coli and expressed upon induction with nalidixic acid, was found almost entirely in the insoluble inclusion bodies (IBs). The proteins were solubilized, refolded and purified to homogeneity by anion-exchange chromatography and gel-filtration. The respective yield of dimers and monomers was 50-100mg from 5L of fermentation culture. Circular dichroism analyses revealed similarity of the purified pfLEP secondary structure to that of mammalian leptins. The purified monomers and dimers showed a single band of approximately 15 kDa following SDS-PAGE in the presence of reducing agent, whereas the dimer showed one band of approximately 30 kDa in the absence of reducing agent, indicating its formation by S-S bonds. The purified product also showed a single peak following gel-filtration under nondenaturating conditions and reverse-phase chromatography. Monomeric and dimeric pfLEPs were stable for at least 6 months in sterile solution frozen at -20 degrees C or as lyophilized powder. Both pfLEPs were biologically active in promoting proliferation of BAF/3 cells stably transfected with the long form of human leptin (hLEP) receptor, but their activity was four to five orders of magnitude lower than that of hLEP. The specificity of this activity was further evidenced by its complete inhibition by hLEP antagonist. In contrast to mammalian leptins, neither form of pfLEP bound to or formed 1:1 complex with chicken leptin-binding domain, likely due to low affinity. No specific binding of either ovine or pufferfish leptins to tilapia liver membranes was detected. This work is the first report on the purification of leptin from any fish species.
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Affiliation(s)
- M Yacobovitz
- Institute of Biochemistry, Food Science and Nutrition, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100, Israel
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Tan D, Johnson DA, Wu W, Zeng L, Chen YH, Chen WY, Vonderhaar BK, Walker AM. Unmodified Prolactin (PRL) and S179D PRL-Initiated Bioluminescence Resonance Energy Transfer between Homo- and Hetero-Pairs of Long and Short Human PRL Receptors in Living Human Cells. Mol Endocrinol 2005; 19:1291-303. [PMID: 15695371 DOI: 10.1210/me.2004-0304] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
AbstractWe have used bioluminescence resonance energy transfer (BRET) to examine the interaction between human prolactins (PRLs) and the long (LF) and two short isoforms (SF1a and SF1b) of the human PRL receptor in living cells. cDNA sequences encoding the LF, SF1a, and SF1b were subcloned into codon-humanized vectors containing cDNAs for either Renilla reniformis luciferase (Rluc) or a green fluorescent protein (GFP2) with a 12- or 13-amino acid linker connecting the parts of the fusion proteins. Transfection into human embryonic kidney 293 cells demonstrated maintained function of Rluc and GFP2 when linked to the receptors, and confocal microscopy demonstrated the localization of tagged receptors in the plasma membrane by 48 h after transfection. All three tagged receptors transduced a signal, with the LF and SF1a stimulating, and SF1b inhibiting, promoter activity of an approximately 2.4-kb β-casein-luc construct. Both unmodified PRL (U-PRL) and the molecular mimic of phosphorylated PRL, S179D PRL, induced BRET with all combinations of long and short receptor isoforms except SF1a plus SF1b. No BRET was observed with the site two-inactive mutant, G129R PRL. This is the first demonstration, 1) that species homologous PRL promotes both homo- and hetero-interaction of most long and short PRLR pairs in living cells, 2) that both U-PRL and S179D PRL are active in this regard, and 3) that there is some aspect of SF1a-SF1b structure that prevents this particular hetero-receptor pairing. In addition, we conclude that preferential pairing of different receptor isoforms is not the explanation for the different signaling initiated by U-PRL and S179D PRL.
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Affiliation(s)
- Dunyong Tan
- Division of Biomedical Sciences, University of California-Riverside, Riverside, CA 92521-0121, USA
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Noel S, Herman A, Johnson GA, Gray CA, Stewart MD, Bazer FW, Gertler A, Spencer TE. Ovine placental lactogen specifically binds to endometrial glands of the ovine uterus. Biol Reprod 2003; 68:772-80. [PMID: 12604625 DOI: 10.1095/biolreprod.102.009183] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
A hormonal servomechanism has been proposed to regulate differentiation and function of the endometrial glandular epithelium (GE) in the ovine uterus during pregnancy. This mechanism involves sequential actions of estrogen, progesterone, ovine interferon tau (IFNtau), placental lactogen (oPL), and placental growth hormone (oGH). The biological actions of oPL in vitro are mediated by homodimerization of the prolactin receptor (oPRLR) and heterodimerization of the oPRLR and oGH receptor. The objectives of the study were to determine the effects of intrauterine oPL, oGH, and their combination on endometrial histoarchitecture and gene expression and to localize and characterize binding sites for oPL in the ovine uterus in vivo using an in situ ligand binding assay. Intrauterine infusion of oPL and/or oGH following IFNtau into ovariectomized ewes treated with progesterone daily differentially affected endometrial gland number and expression of uterine milk proteins and osteopontin. However, neither hormone affected PRLR, insulin-like growth factor (IGF)-I, or IGF-II mRNA levels in the endometrium. A chimeric protein of placental secretory alkaline phosphatase (SEAP) and oPL was used to identify and characterize binding sites for oPL in frozen sections of interplacentomal endometrium from pregnant ewes. Specific binding of SEAP-oPL was detected in the endometrial GE on Days 30, 60, 90, and 120 of pregnancy. In Day 90 endometrium, SEAP-oPL binding to the endometrial GE was displaced completely by oPL and prolactin (oPRL) but only partially by oGH. Binding experiments using the extracellular domain of the oPRLR also showed that iodinated oPL binding sites could be competed for by oPRL and oPL but not by oGH. Collectively, results indicate that oPL binds to receptors in the endometrial glands and that oPRL is more effective than oGH in competing for these binding sites. Thus, effects of oPL on the endometrial glands may be mediated by receptors for oPRL and oGH.
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Affiliation(s)
- Sekoni Noel
- Center for Animal Biotechnology and Genomics and Department of Animal Science, Texas A&M University, College Station, Texas 77843-2471, USA
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Raver N, Vardy E, Livnah O, Devos R, Gertler A. Comparison of R128Q mutations in human, ovine, and chicken leptins. Gen Comp Endocrinol 2002; 126:52-8. [PMID: 11944966 DOI: 10.1006/gcen.2001.7766] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Human leptin and its R128Q mutant, as well as the R128Q mutants of ovine and chicken leptins, were prepared, expressed in Escherichia coli, refolded, and purified to homogeneity yielding electrophoretically pure, over 95% monomeric protein. R128Q mutations did not change the binding properties to BAF/3 cells stably transfected with the long form of human leptin receptor compared, respectively, to non-mutated human, ovine, and chicken leptins. In contrast, the biological activity tested in a proliferation assay in the same cells was drastically changed. Human leptin R128Q lost its activity and even became a weak antagonist, whereas the activities of ovine and chicken leptins were reduced 25- and 80-fold. If dimerization models were applicable leptin receptor activation, the present results would suggest that site 2 of the hormone was impaired. Two models, the human growth hormone:human growth hormone receptor (hGH:hGHR) (1:2) and the granulocyte-colony stimulating factor:granulocyte-colony stimulating factor receptor (GCSF:GCSFR) (2:2) complexes, were used for modeling. Superimposing the leptin structure on the hGH and GCSF models in the complex structures did not indicate any role for R128 in receptor binding. This made it impossible to correlate the results shown in the present work with the currently available models. Therefore, leptin may bind its receptors in a manner different than those proposed until now.
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Affiliation(s)
- Nina Raver
- Institute of Biochemistry, Food Science and Nutrition, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot 76100, Israel
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Abstract
Ruminant placental lactogens (PLs) are structurally related to prolactins (PRLs) and growth hormones (GHs) and are secreted by placentae. Ruminant PLs are unusual in their capacity to bind and activate PRL and GH receptors (Rs) from other species. The present minireview summarizes several works showing that unlike in heterologous species (rat, rabbit, human), in homologous (ruminant) species, PLs act by activating PRLRs or by heterodimerizing GHRs and PRLRs, and suggests that this may be the main mechanism of PL action in vivo. Mutations impairing the ability of ovine (o)PL or bovine (b)PL to form complexes with PRLRs (but not with GHRs) do not cause loss of biological activity, because the transient existence of the homodimeric complex is still sufficient to initiate the signal transduction; however, mutants do lose their ability to activate homologous PRLRs. To explain this difference, we proposed a novel term-minimal time of homodimer persistence-which assumes that to initiate the signal transduction, a "minimal time" of homodimer existence is required for transphosphorylation of associated JAK2s. In interactions between ruminant PLs and homologous PRLRs, this minimal time is met through the interaction with homologous PRLRs, which has a shorter half-life than with heterologous PRLRs. Thus oPL or bPL are active in cells possessing both homologous and heterologous PRLRs. Mutations of PLs decrease the affinity, shortening the "time of homodimer persistence." In heterologous interactions, the minimal time is still sufficient to initiate the biological activity, whereas in homologous interactions, which in any case are weaker, further destabilization of the complex shortens its persistence below the minimal time, causing loss of biological activity.
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Affiliation(s)
- Arieh Gertler
- Institute of Biochemistry, Food Science and Nutrition, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
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Abstract
The protein hormone prolactin (PRL) was first discovered as an anterior pituitary factor capable of stimulating milk production in mammals. We now know that PRL has over 300 different functions in vertebrates. In fish, PRL plays an important role in freshwater osmoregulation by preventing both the loss of ions and the uptake of water. This paper will review what is currently known about the structure and evolution of fish PRL and its mechanisms of action in relation to the maintenance of hydromineral balance. Historically, functional studies of fish PRL were carried out using heterologous PRLs and the results varied greatly between experiments and species. In some cases this variability was due to the ability of these PRLs to bind to both growth hormone and PRL receptors. In fact, a recurring theme in the literature is that the actions of PRL cannot be generalized to all fish due to marked differences between species. Many of the effects of PRL on hydromineral balance are specific to euryhaline fish, which is appropriate given that they frequently experience sudden changes in environmental salinity. Much of the recent work has focused on the isolation and characterization of fish PRLs and their receptors. These studies have provided the necessary tools to obtain a better understanding of the evolution of PRL and its role in osmoregulation.
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Affiliation(s)
- Lori A Manzon
- Division of Life Sciences, University of Toronto at Scarborough, 1265 Military Trail, Toronto, Ontario, MIC 1A4, Canada.
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