title: Loss-of-Function Mutations in the Human Luteinizing Hormone Receptor Predominantly Cause Intracellular Retention.
abstract: Mutations in G protein-coupled receptors (GPCRs) have been identified for many endocrine hormone signaling deficiencies. Inactivating mutations can impair ligand binding, receptor activation/coupling to signaling pathways, or can cause receptor misfolding and consequent impaired expression at the cell membrane. Here we examine the cell surface expression, ligand binding, and signaling of a range of mutant human luteinizing hormone receptors (LHRs) identified as causing reproductive dysfunction in human patients. The data obtained reveal how mutations in GPCRs can have diverse and severely deleterious effects on receptor function. Furthermore, it was found that impaired functionality of the majority of the mutant LHRs was due to reduced expression at the cell surface (14/20) while only two mutations caused impaired binding affinity and two impaired in signaling. An additional two mutations were found to cause no impairment of receptor function. These data demonstrate that the majority of LHR mutations lead to intracellular retention and highlight the potential for novel pharmacological chaperone therapeutics that can "rescue" expression/function of retained mutant GPCRs.
authors.affiliation: Centre for Neuroendocrinology (C.L.N., R.C.A., R.P.M.), Faculty of Health Sciences, University of Pretoria, Pretoria, 0001, South Africa; Department of Immunology (C.L.N), Faculty of Health Sciences, University of Pretoria, Pretoria, 0001, South Africa; UCT/MRC Receptor Biology Research Unit, Department of Integrative Biomedical Sciences and Institute of Infectious Diseases and Molecular Medicine (C.L.N., R.C.A., A.A.K., R.P.M.), Faculty of Health Sciences, University of Cape Town, Cape Town 7700, South Africa; Department of Zoology and Entomology (R.C.A), Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, 0028, South Africa; SAMRC Gynaecology Cancer Research Centre (A.A.K), Department of Integrative Biomedical Sciences and Institute of Infectious Diseases and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, 7700, South Africa; and Department of Physiology (R.P.M), Faculty of Health Sciences, University of Pretoria, Pretoria, 0007, South Africa.
authors.forename: Claire Louise
authors.initials: CL
authors.lastname: Newton
authors.affiliation: Centre for Neuroendocrinology (C.L.N., R.C.A., R.P.M.), Faculty of Health Sciences, University of Pretoria, Pretoria, 0001, South Africa; Department of Immunology (C.L.N), Faculty of Health Sciences, University of Pretoria, Pretoria, 0001, South Africa; UCT/MRC Receptor Biology Research Unit, Department of Integrative Biomedical Sciences and Institute of Infectious Diseases and Molecular Medicine (C.L.N., R.C.A., A.A.K., R.P.M.), Faculty of Health Sciences, University of Cape Town, Cape Town 7700, South Africa; Department of Zoology and Entomology (R.C.A), Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, 0028, South Africa; SAMRC Gynaecology Cancer Research Centre (A.A.K), Department of Integrative Biomedical Sciences and Institute of Infectious Diseases and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, 7700, South Africa; and Department of Physiology (R.P.M), Faculty of Health Sciences, University of Pretoria, Pretoria, 0007, South Africa.
authors.forename: Ross Calley
authors.initials: RC
authors.lastname: Anderson
authors.affiliation: Centre for Neuroendocrinology (C.L.N., R.C.A., R.P.M.), Faculty of Health Sciences, University of Pretoria, Pretoria, 0001, South Africa; Department of Immunology (C.L.N), Faculty of Health Sciences, University of Pretoria, Pretoria, 0001, South Africa; UCT/MRC Receptor Biology Research Unit, Department of Integrative Biomedical Sciences and Institute of Infectious Diseases and Molecular Medicine (C.L.N., R.C.A., A.A.K., R.P.M.), Faculty of Health Sciences, University of Cape Town, Cape Town 7700, South Africa; Department of Zoology and Entomology (R.C.A), Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, 0028, South Africa; SAMRC Gynaecology Cancer Research Centre (A.A.K), Department of Integrative Biomedical Sciences and Institute of Infectious Diseases and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, 7700, South Africa; and Department of Physiology (R.P.M), Faculty of Health Sciences, University of Pretoria, Pretoria, 0007, South Africa.
authors.forename: Arieh Anthony
authors.initials: AA
authors.lastname: Katz
authors.affiliation: Centre for Neuroendocrinology (C.L.N., R.C.A., R.P.M.), Faculty of Health Sciences, University of Pretoria, Pretoria, 0001, South Africa; Department of Immunology (C.L.N), Faculty of Health Sciences, University of Pretoria, Pretoria, 0001, South Africa; UCT/MRC Receptor Biology Research Unit, Department of Integrative Biomedical Sciences and Institute of Infectious Diseases and Molecular Medicine (C.L.N., R.C.A., A.A.K., R.P.M.), Faculty of Health Sciences, University of Cape Town, Cape Town 7700, South Africa; Department of Zoology and Entomology (R.C.A), Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, 0028, South Africa; SAMRC Gynaecology Cancer Research Centre (A.A.K), Department of Integrative Biomedical Sciences and Institute of Infectious Diseases and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, 7700, South Africa; and Department of Physiology (R.P.M), Faculty of Health Sciences, University of Pretoria, Pretoria, 0007, South Africa.
authors.forename: Robert Peter
authors.initials: RP
authors.lastname: Millar
mesh_terms: D000595:Amino Acid Sequence; D004797:Enzyme-Linked Immunosorbent Assay; D043802:GTP-Binding Protein alpha Subunits, Gq-G11 / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D011485:Protein Binding / Q000235:genetics / Q000502:physiology; D011974:Receptors, LH / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology
chemical_list: D011974:Receptors, LH; C112631:G protein alpha 16; D043802:GTP-Binding Protein alpha Subunits, Gq-G11