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Abstract
Ceramides have emerged as important regulators of tissue metabolism that play essential roles in cardiometabolic disease. They are potent biomarkers of diabetes and heart disease and are now being measured clinically as predictors of major adverse cardiac events. Moreover, studies in rodents reveal that inhibitors of ceramide synthesis prevent or reverse the pathogenic features of type 2 diabetes, nonalcoholic fatty liver disease, atherosclerosis, and cardiomyopathy. Herein the authors discuss inhibition of dihydroceramide desaturase-1, the final enzyme in the ceramide biosynthesis pathway, as a potential therapeutic approach to lower ceramides and combat cardiometabolic disease.
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Affiliation(s)
| | - Liping Wang
- Diabetes and Metabolism Research Center, Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, USA
| | - Scott A Summers
- Diabetes and Metabolism Research Center, Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, USA
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2
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Cocce KJ, Jasper JS, Desautels TK, Everett L, Wardell S, Westerling T, Baldi R, Wright TM, Tavares K, Yllanes A, Bae Y, Blitzer JT, Logsdon C, Rakiec DP, Ruddy DA, Jiang T, Broadwater G, Hyslop T, Hall A, Laine M, Phung L, Greene GL, Martin LA, Pancholi S, Dowsett M, Detre S, Marks JR, Crawford GE, Brown M, Norris JD, Chang CY, McDonnell DP. The Lineage Determining Factor GRHL2 Collaborates with FOXA1 to Establish a Targetable Pathway in Endocrine Therapy-Resistant Breast Cancer. Cell Rep 2019; 29:889-903.e10. [PMID: 31644911 PMCID: PMC6874102 DOI: 10.1016/j.celrep.2019.09.032] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 07/02/2019] [Accepted: 09/12/2019] [Indexed: 12/25/2022] Open
Abstract
Notwithstanding the positive clinical impact of endocrine therapies in estrogen receptor-alpha (ERα)-positive breast cancer, de novo and acquired resistance limits the therapeutic lifespan of existing drugs. Taking the position that resistance is nearly inevitable, we undertook a study to identify and exploit targetable vulnerabilities that were manifest in endocrine therapy-resistant disease. Using cellular and mouse models of endocrine therapy-sensitive and endocrine therapy-resistant breast cancer, together with contemporary discovery platforms, we identified a targetable pathway that is composed of the transcription factors FOXA1 and GRHL2, a coregulated target gene, the membrane receptor LYPD3, and the LYPD3 ligand, AGR2. Inhibition of the activity of this pathway using blocking antibodies directed against LYPD3 or AGR2 inhibits the growth of endocrine therapy-resistant tumors in mice, providing the rationale for near-term clinical development of humanized antibodies directed against these proteins.
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Affiliation(s)
- Kimberly J Cocce
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Jeff S Jasper
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Taylor K Desautels
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Logan Everett
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - Suzanne Wardell
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Thomas Westerling
- Center for Functional Cancer Epigenetics, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Robert Baldi
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Tricia M Wright
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Kendall Tavares
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Alex Yllanes
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Yeeun Bae
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | | | - Craig Logsdon
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77054, USA
| | - Daniel P Rakiec
- Novartis Institutes for Biomedical Research, Oncology Disease Area, Cambridge, MA 02139, USA
| | - David A Ruddy
- Novartis Institutes for Biomedical Research, Oncology Disease Area, Cambridge, MA 02139, USA
| | - Tiancong Jiang
- Department of Biostatistics, Duke Cancer Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Gloria Broadwater
- Department of Biostatistics, Duke Cancer Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Terry Hyslop
- Department of Biostatistics, Duke Cancer Institute, Duke University School of Medicine, Durham, NC 27710, USA
| | - Allison Hall
- Department of Pathology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Muriel Laine
- The Ben May Department for Cancer Research, The University of Chicago, Chicago, IL 60637, USA
| | - Linda Phung
- The Ben May Department for Cancer Research, The University of Chicago, Chicago, IL 60637, USA
| | - Geoffrey L Greene
- The Ben May Department for Cancer Research, The University of Chicago, Chicago, IL 60637, USA
| | - Lesley-Ann Martin
- Breast Cancer Now, Toby Robins Research Centre, Institute of Cancer Research, London, SW3 6JB, UK
| | - Sunil Pancholi
- Breast Cancer Now, Toby Robins Research Centre, Institute of Cancer Research, London, SW3 6JB, UK
| | - Mitch Dowsett
- Ralph Lauren Centre for Breast Cancer Research, Royal Marsden Hospital NHS Trust, London, SW3 6JJ, UK
| | - Simone Detre
- Ralph Lauren Centre for Breast Cancer Research, Royal Marsden Hospital NHS Trust, London, SW3 6JJ, UK
| | - Jeffrey R Marks
- Department of Surgery, Duke University School of Medicine, Durham, NC 27710, USA
| | - Gregory E Crawford
- Department of Pediatrics, Duke University School of Medicine, Durham, NC 27710, USA
| | - Myles Brown
- Center for Functional Cancer Epigenetics, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - John D Norris
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Ching-Yi Chang
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Donald P McDonnell
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA.
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Wardell SE, Yllanes AP, Chao CA, Bae Y, Andreano KJ, Desautels TK, Heetderks KA, Blitzer JT, Norris JD, McDonnell DP. Pharmacokinetic and pharmacodynamic analysis of fulvestrant in preclinical models of breast cancer to assess the importance of its estrogen receptor-α degrader activity in antitumor efficacy. Breast Cancer Res Treat 2019; 179:67-77. [PMID: 31562570 PMCID: PMC6985185 DOI: 10.1007/s10549-019-05454-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 09/19/2019] [Indexed: 12/11/2022]
Abstract
Purpose Fulvestrant is a selective estrogen receptor downregulator (SERD) that is approved for first- or second-line use as a single agent or in combination with cyclin dependent kinase or phosphatidylinositol 3-kinase inhibitors for the treatment of metastatic breast cancer. Fulvestrant exhibits exceptionally effective antitumor activity in preclinical models of breast cancer, a success that has been attributed to its robust SERD activity despite modest receptor downregulation in patient tumors. By modeling human exposures in animal models we probe the absolute need for SERD activity. Methods Three xenograft models of endocrine therapy-resistant breast cancer were used to evaluate the efficacy of fulvestrant administered in doses historically used in preclinical studies in the field or by using a dose regimen intended to model clinical exposure levels. Pharmacokinetic and pharmacodynamic analyses were conducted to evaluate plasma exposure and intratumoral ER downregulation. Results A clinically relevant 25 mg/kg dose of fulvestrant exhibited antitumor efficacy comparable to the historically used 200 mg/kg dose, but at this lower dose it did not result in robust ER downregulation. Further, the antitumor efficacy of the lower dose of fulvestrant was comparable to that observed for other oral SERDs currently in development. Conclusion The use of clinically unachievable exposure levels of fulvestrant as a benchmark in preclinical development of SERDs may negatively impact the selection of those molecules that are advanced for clinical development. Further, these studies suggest that antagonist efficacy, as opposed to SERD activity, is likely to be the primary driver of clinical response. Electronic supplementary material The online version of this article (10.1007/s10549-019-05454-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Suzanne E Wardell
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Box 3813, Durham, NC, 27710, USA
| | - Alexander P Yllanes
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Box 3813, Durham, NC, 27710, USA
| | - Christina A Chao
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Box 3813, Durham, NC, 27710, USA
| | - Yeeun Bae
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Box 3813, Durham, NC, 27710, USA
| | - Kaitlyn J Andreano
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Box 3813, Durham, NC, 27710, USA
| | - Taylor K Desautels
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Box 3813, Durham, NC, 27710, USA
| | - Kendall A Heetderks
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Box 3813, Durham, NC, 27710, USA
| | | | - John D Norris
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Box 3813, Durham, NC, 27710, USA
| | - Donald P McDonnell
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Box 3813, Durham, NC, 27710, USA.
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Wu X, Romero D, Swiatek WI, Dorweiler I, Kikani CK, Sabic H, Zweifel BS, McKearn J, Blitzer JT, Nickols GA, Rutter J. PAS kinase drives lipogenesis through SREBP-1 maturation. Cell Rep 2014; 8:242-55. [PMID: 25001282 DOI: 10.1016/j.celrep.2014.06.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 05/16/2014] [Accepted: 06/04/2014] [Indexed: 12/21/2022] Open
Abstract
Elevated hepatic synthesis of fatty acids and triglycerides, driven by hyperactivation of the SREBP-1c transcription factor, has been implicated as a causal feature of metabolic syndrome. SREBP-1c activation requires the proteolytic maturation of the endoplasmic-reticulum-bound precursor to the active, nuclear transcription factor, which is stimulated by feeding and insulin signaling. Here, we show that feeding and insulin stimulate the hepatic expression of PASK. We also demonstrate, using genetic and pharmacological approaches, that PASK is required for the proteolytic maturation of SREBP-1c in cultured cells and in the mouse and rat liver. Inhibition of PASK improves lipid and glucose metabolism in dietary animal models of obesity and dyslipidemia. Administration of a PASK inhibitor decreases hepatic expression of lipogenic SREBP-1c target genes, decreases serum triglycerides, and partially reverses insulin resistance. While the signaling network that controls SREBP-1c activation is complex, we propose that PASK is an important component with therapeutic potential.
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Affiliation(s)
- Xiaoying Wu
- Department of Biochemistry, University of Utah School of Medicine, 15 N. Medical Drive East, Salt Lake City, UT 84112-5650, USA
| | - Donna Romero
- Synergenics, 1700 Owens Street, Suite 515, San Francisco, CA 94158, USA
| | - Wojciech I Swiatek
- Department of Biochemistry, University of Utah School of Medicine, 15 N. Medical Drive East, Salt Lake City, UT 84112-5650, USA
| | - Irene Dorweiler
- Department of Biochemistry, University of Utah School of Medicine, 15 N. Medical Drive East, Salt Lake City, UT 84112-5650, USA
| | - Chintan K Kikani
- Department of Biochemistry, University of Utah School of Medicine, 15 N. Medical Drive East, Salt Lake City, UT 84112-5650, USA
| | - Hana Sabic
- Department of Biochemistry, University of Utah School of Medicine, 15 N. Medical Drive East, Salt Lake City, UT 84112-5650, USA
| | - Ben S Zweifel
- Synergenics, 1700 Owens Street, Suite 515, San Francisco, CA 94158, USA
| | - John McKearn
- Synergenics, 1700 Owens Street, Suite 515, San Francisco, CA 94158, USA
| | - Jeremy T Blitzer
- Synergenics, 1700 Owens Street, Suite 515, San Francisco, CA 94158, USA
| | - G Allen Nickols
- Synergenics, 1700 Owens Street, Suite 515, San Francisco, CA 94158, USA
| | - Jared Rutter
- Department of Biochemistry, University of Utah School of Medicine, 15 N. Medical Drive East, Salt Lake City, UT 84112-5650, USA.
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Abstract
BACKGROUND The Wnt signaling pathway regulates many processes during embryonic development, including axis specification, organogenesis, angiogenesis, and stem cell proliferation. Wnt signaling has also been implicated in a number of cancers, bone density maintenance, and neurological conditions during adulthood. While numerous Wnts, their cognate receptors of the Frizzled and Arrow/LRP5/6 families and downstream pathway components have been identified, little is known about the initial events occurring directly after receptor activation. RESULTS We show here that Wnt proteins are rapidly endocytosed by a clathrin- and dynamin-mediated process. While endocytosis has traditionally been considered a principal mechanism for receptor down-regulation and termination of signaling pathways, we demonstrate that interfering with clathrin-mediated endocytosis actually blocks Wnt signaling at the level of beta-catenin accumulation and target gene expression. CONCLUSION A necessary component of Wnt signaling occurs in a subcellular compartment distinct from the plasma membrane. Moreover, as internalized Wnts transit partially through the transferrin recycling pathway, it is possible that a "signaling endosome" serves as a nexus for activated Wnt pathway components.
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Affiliation(s)
- Jeremy T Blitzer
- Howard Hughes Medical Institute and Department of Developmental Biology, Stanford University School of Medicine, Stanford, California 94305, USA
| | - Roel Nusse
- Howard Hughes Medical Institute and Department of Developmental Biology, Stanford University School of Medicine, Stanford, California 94305, USA
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Foletti DL, Blitzer JT, Scheller RH. Physiological modulation of rabphilin phosphorylation. J Neurosci 2001; 21:5473-83. [PMID: 11466418 PMCID: PMC6762674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2001] [Revised: 05/11/2001] [Accepted: 05/17/2001] [Indexed: 02/20/2023] Open
Abstract
The dynamic modulation of protein function by phosphorylation plays an important role in regulating synaptic plasticity. Several proteins involved in synaptic transmission have been shown to be targets of protein kinases and phosphatases. A thorough analysis of the physiological role of these modifications has been hampered by the lack of reagents that specifically recognize the phosphorylated states of these proteins. In this study we analyze the physiological modulation of rabphilin using phosphospecific antibodies. We show that phosphorylation on serine-234 and serine-274 of rabphilin is dynamically regulated both under basal and stimulated conditions by the activity of kinases and phosphatases. The two sites are differentially phosphorylated by the stimulation of various kinases, suggesting a possible convergence of different pathways to modulate the function of the protein. Maximal stimulation was observed under plasma membrane-depolarizing conditions that trigger synaptic vesicle exocytosis. The increase in phosphorylation was critically dependent on external Ca(2+) and on the presence of Rab3a, a small GTPase that recruits rabphilin to synaptic vesicles. The rapid phosphorylation and dephosphorylation during and after stimulation demonstrates the transient nature of the modification. Our results indicate that rabphilin is phosphorylated on synaptic vesicles by Ca(2+)-dependent kinases that become active in synaptic terminals during exocytosis. We have found that phosphorabphilin has a reduced affinity for membranes; we therefore propose that the modulation of the membrane association of rabphilin has a role in the synaptic vesicle life cycle, perhaps in vesicle mobilization in preparation for subsequent rounds of neurotransmission.
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Affiliation(s)
- D L Foletti
- Howard Hughes Medical Institute, Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California 94305-5428, USA
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Maudsley S, Zamah AM, Rahman N, Blitzer JT, Luttrell LM, Lefkowitz RJ, Hall RA. Platelet-derived growth factor receptor association with Na(+)/H(+) exchanger regulatory factor potentiates receptor activity. Mol Cell Biol 2000; 20:8352-63. [PMID: 11046132 PMCID: PMC102142 DOI: 10.1128/mcb.20.22.8352-8363.2000] [Citation(s) in RCA: 171] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Platelet-derived growth factor (PDGF) is a potent mitogen for many cell types. The PDGF receptor (PDGFR) is a receptor tyrosine kinase that mediates the mitogenic effects of PDGF by binding to and/or phosphorylating a variety of intracellular signaling proteins upon PDGF-induced receptor dimerization. We show here that the Na(+)/H(+) exchanger regulatory factor (NHERF; also known as EBP50), a protein not previously known to interact with the PDGFR, binds to the PDGFR carboxyl terminus (PDGFR-CT) with high affinity via a PDZ (PSD-95/Dlg/Z0-1 homology) domain-mediated interaction and potentiates PDGFR autophosphorylation and extracellular signal-regulated kinase (ERK) activation in cells. A point-mutated version of the PDGFR, with the terminal leucine changed to alanine (L1106A), cannot bind NHERF in vitro and is markedly impaired relative to the wild-type receptor with regard to PDGF-induced autophosphorylation and activation of ERK in cells. NHERF potentiation of PDGFR signaling depends on the capacity of NHERF to oligomerize. NHERF oligomerizes in vitro when bound with PDGFR-CT, and a truncated version of the first NHERF PDZ domain that can bind PDGFR-CT but which does not oligomerize reduces PDGFR tyrosine kinase activity when transiently overexpressed in cells. PDGFR activity in cells can also be regulated in a NHERF-dependent fashion by stimulation of the beta(2)-adrenergic receptor, a known cellular binding partner for NHERF. These findings reveal that NHERF can directly bind to the PDGFR and potentiate PDGFR activity, thus elucidating both a novel mechanism by which PDGFR activity can be regulated and a new cellular role for the PDZ domain-containing adapter protein NHERF.
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Affiliation(s)
- S Maudsley
- Howard Hughes Medical Institute, Departments of Medicine and Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
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Hall RA, Spurney RF, Premont RT, Rahman N, Blitzer JT, Pitcher JA, Lefkowitz RJ. G protein-coupled receptor kinase 6A phosphorylates the Na(+)/H(+) exchanger regulatory factor via a PDZ domain-mediated interaction. J Biol Chem 1999; 274:24328-34. [PMID: 10446210 DOI: 10.1074/jbc.274.34.24328] [Citation(s) in RCA: 121] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Na(+)/H(+) exchanger regulatory factor (NHERF) is constitutively phosphorylated in cells, but the site(s) of this phosphorylation and the kinase(s) responsible for it have not been identified. We show here that the primary site of constitutive NHERF phosphorylation in human embryonic kidney 293 (HEK-293) cells is Ser(289), and that the stoichiometry of phosphorylation is near 1 mol/mol. NHERF contains two PDZ domains that recognize the sequence S/T-X-L at the carboxyl terminus of target proteins, and thus we examined the possibility that kinases containing this motif might associate with and phosphorylate NHERF. Overlay experiments and co-immunoprecipitation studies revealed that NHERF binds with high affinity to a splice variant of the G protein-coupled receptor kinase 6, GRK6A, which terminates in the motif T-R-L. NHERF does not associate with GRK6B or GRK6C, alternatively spliced variants that differ from GRK6A at their extreme carboxyl termini. GRK6A phosphorylates NHERF efficiently on Ser(289) in vitro, whereas GRK6B, GRK6C, and GRK2 do not. Furthermore, the endogenous "NHERF kinase" activity in HEK-293 cell lysates is sensitive to treatments that alter the activity of GRK6A. These data suggest that GRK6A phosphorylates NHERF via a PDZ domain-mediated interaction and that GRK6A is the kinase in HEK-293 cells responsible for the constitutive phosphorylation of NHERF.
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Affiliation(s)
- R A Hall
- Howard Hughes Medical Institute, Departments of Medicine and Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA
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Hall RA, Ostedgaard LS, Premont RT, Blitzer JT, Rahman N, Welsh MJ, Lefkowitz RJ. A C-terminal motif found in the beta2-adrenergic receptor, P2Y1 receptor and cystic fibrosis transmembrane conductance regulator determines binding to the Na+/H+ exchanger regulatory factor family of PDZ proteins. Proc Natl Acad Sci U S A 1998; 95:8496-501. [PMID: 9671706 PMCID: PMC21104 DOI: 10.1073/pnas.95.15.8496] [Citation(s) in RCA: 329] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/26/1998] [Indexed: 02/08/2023] Open
Abstract
The Na+/H+ exchanger regulatory factor (NHERF) binds to the tail of the beta2-adrenergic receptor and plays a role in adrenergic regulation of Na+/H+ exchange. NHERF contains two PDZ domains, the first of which is required for its interaction with the beta2 receptor. Mutagenesis studies of the beta2 receptor tail revealed that the optimal C-terminal motif for binding to the first PDZ domain of NHERF is D-S/T-x-L, a motif distinct from those recognized by other PDZ domains. The first PDZ domain of NHERF-2, a protein that is 52% identical to NHERF and also known as E3KARP, SIP-1, and TKA-1, exhibits binding preferences very similar to those of the first PDZ domain of NHERF. The delineation of the preferred binding motif for the first PDZ domain of the NHERF family of proteins allows for predictions for other proteins that may interact with NHERF or NHERF-2. For example, as would be predicted from the beta2 receptor tail mutagenesis studies, NHERF binds to the tail of the purinergic P2Y1 receptor, a seven-transmembrane receptor with an intracellular C-terminal tail ending in D-T-S-L. NHERF also binds to the tail of the cystic fibrosis transmembrane conductance regulator, which ends in D-T-R-L. Because the preferred binding motif of the first PDZ domain of the NHERF family of proteins is found at the C termini of a variety of intracellular proteins, NHERF and NHERF-2 may be multifunctional adaptor proteins involved in many previously unsuspected aspects of intracellular signaling.
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Affiliation(s)
- R A Hall
- Howard Hughes Medical Institute, Departments of Medicine and Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
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10
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Hall RA, Premont RT, Chow CW, Blitzer JT, Pitcher JA, Claing A, Stoffel RH, Barak LS, Shenolikar S, Weinman EJ, Grinstein S, Lefkowitz RJ. The beta2-adrenergic receptor interacts with the Na+/H+-exchanger regulatory factor to control Na+/H+ exchange. Nature 1998; 392:626-30. [PMID: 9560162 DOI: 10.1038/33458] [Citation(s) in RCA: 477] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Stimulation of beta2-adrenergic receptors on the cell surface by adrenaline or noradrenaline leads to alterations in the metabolism, excitability, differentiation and growth of many cell types. These effects have traditionally been thought to be mediated exclusively by receptor activation of intracellular G proteins. However, certain physiological effects of beta2-adrenergic receptor stimulation, notably the regulation of cellular pH by modulation of Na+/H+ exchanger (NHE) function, do not seem to be entirely dependent on G-protein activation. We report here a direct agonist-promoted association of the beta2-adrenergic receptor with the Na+/H+ exchanger regulatory factor (NHERF), a protein that regulates the activity of the Na+/H+ exchanger type 3 (NHE3). NHERF binds to the beta2-adrenergic receptor by means of a PDZ-domain-mediated interaction with the last few residues of the carboxy-terminal cytoplasmic domain of the receptor. Mutation of the final residue of the beta2-adrenergic receptor from leucine to alanine abolishes the receptor's interaction with NHERF and also markedly alters beta2-adrenergic receptor regulation of NHE3 in cells without altering receptor-mediated activation of adenylyl cyclase. Our findings indicate that agonist-dependent beta2-adrenergic receptor binding of NHERF plays a role in beta2-adrenergic receptor-mediated regulation of Na+/H+ exchange.
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Affiliation(s)
- R A Hall
- Howard Hughes Medical Institute, Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA
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