1
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Lara LS, Gonzalez AA, Hennrikus MT, Prieto MC. Hormone-Dependent Regulation of Renin and Effects on Prorenin Receptor Signaling in the Collecting Duct. Curr Hypertens Rev 2022; 18:91-100. [PMID: 35170417 PMCID: PMC10132771 DOI: 10.2174/1573402118666220216105357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 10/22/2021] [Accepted: 12/13/2021] [Indexed: 01/27/2023]
Abstract
The production of renin by the principal cells of the collecting duct has widened our understanding of the regulation of intrarenal angiotensin II (Ang II) generation and blood pressure. In the collecting duct, Ang II increases the synthesis and secretion of renin by mechanisms involving the activation of Ang II type 1 receptor (AT1R) via stimulation of the PKCα, Ca2+, and cAMP/PKA/CREB pathways. Additionally, paracrine mediators, including vasopressin (AVP), prostaglandins, bradykinin (BK), and atrial natriuretic peptide (ANP), regulate renin in principal cells. During Ang II-dependent hypertension, despite plasma renin activity suppression, renin and prorenin receptor (RPR) are upregulated in the collecting duct and promote de novo formation of intratubular Ang II. Furthermore, activation of PRR by its natural agonists, prorenin and renin, may contribute to the stimulation of profibrotic factors independent of Ang II. Thus, the interactions of RAS components with paracrine hormones within the collecting duct enable tubular compartmentalization of the RAS to orchestrate complex mechanisms that increase intrarenal Ang II, Na+ reabsorption, and blood pressure.
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Affiliation(s)
- Lucienne S Lara
- Instituto de Ciencias Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Alexis A Gonzalez
- Instituto de Química, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Matthew T Hennrikus
- Department of Physiology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Minolfa C Prieto
- Department of Physiology, Tulane University School of Medicine, New Orleans, LA, USA.,Tulane Renal and Hypertension Center of Excellence, Tulane University School of Medicine, New Orleans, LA, USA
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2
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Byambaragchaa M, Joo HE, Kim SG, Kim YJ, Park GE, Min KS. Signal Transduction of C-Terminal Phosphorylation Regions for Equine Luteinizing Hormone/Chorionic Gonadotropin Receptor (eLH/CGR). Dev Reprod 2022; 26:1-12. [PMID: 35528321 PMCID: PMC9042392 DOI: 10.12717/dr.2022.26.1.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 01/04/2022] [Accepted: 02/12/2022] [Indexed: 12/05/2022]
Abstract
This study aimed to investigate the signal transduction of phosphorylation sites
at the carboxyl (C)-terminal region of equine luteinizing hormone/chorionic
gonadotropin receptor (eLH/ CGR). The eLH/CGR has a large extracellular domain
of glycoprotein hormone receptors within the G protein-coupled receptors. We
constructed a mutant (eLH/CGR-t656) of eLH/ CGR, in which the C-terminal
cytoplasmic tail was truncated at the Phe656 residue, through polymerase chain
reaction. The eLH/CGR-t656 removed 14 potential phosphorylation sites in the
intracellular C-terminal region. The plasmids were transfected into Chinese
hamster ovary (CHO)-K1 and PathHunter Parental cells expressing
β-arrestin, and agonist-induced cAMP responsiveness was analyzed. In
CHO-K1 cells, those expressing eLH/CGR-t656 were lower than those expressing
eLH/CGR wild-type (eLH/CGR-wt). The EC50 of the eLH/ CGR-t656 mutant
was approximately 72.2% of the expression observed in eLH/CGR-wt. The maximal
response in eLH/CGR-t656 also decreased to approximately 43% of that observed in
eLH/CGR-wt. However, in PathHunter Parental cells, cAMP activity and maximal
response of the eLH/CGR-t656 mutant were approximately 173.5% and 100.8%,
respectively, of that of eLH/CGR-wt. These results provide evidence that the
signal transduction of C-terminal phosphorylation in eLH/CGR plays a pivotal
role in CHO-K1 cells. The cAMP level was recovered in PathHunter Parental cells
expressing β-arrestin. We suggest that the signal transduction of the
C-terminal region phosphorylation sites is remarkably different depending on the
cells expressing β-arrestin in CHO-K1 cells.
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Affiliation(s)
| | - Hyo-Eun Joo
- Division of Animal Science, School of Animal Life Convergence Sciences, Hankyong National University, Anseong 17579, Korea
| | - Sang-Gwon Kim
- Division of Animal Science, School of Animal Life Convergence Sciences, Hankyong National University, Anseong 17579, Korea
| | - Yean-Ji Kim
- Division of Animal Science, School of Animal Life Convergence Sciences, Hankyong National University, Anseong 17579, Korea
| | - Gyeong-Eun Park
- Division of Animal Science, School of Animal Life Convergence Sciences, Hankyong National University, Anseong 17579, Korea
| | - Kwan-Sik Min
- Institute of Genetic Engineering, Hankyong National University, Anseong 17579, Korea.,Division of Animal Science, School of Animal Life Convergence Sciences, Hankyong National University, Anseong 17579, Korea
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3
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Activating and inactivating mutations of the human, rat, equine and eel luteinizing hormone/ chorionic gonadotropin receptors (LH/CGRs). JOURNAL OF ANIMAL REPRODUCTION AND BIOTECHNOLOGY 2021. [DOI: 10.12750/jarb.36.4.169] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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4
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Byambaragchaa M, Choi SH, Joo HE, Kim SG, Kim YJ, Park GE, Kang MH, Min KS. Specific Biological Activity of Equine Chorionic Gonadotropin (eCG) Glycosylation Sites in Cells Expressing Equine Luteinizing Hormone/CG (eLH/CG) Receptor. Dev Reprod 2021; 25:199-211. [PMID: 35141446 PMCID: PMC8807129 DOI: 10.12717/dr.2021.25.4.199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 11/02/2021] [Accepted: 11/23/2021] [Indexed: 11/30/2022]
Abstract
Equine chorionic gonadotropin (eCG), produced by the endometrial cups of the
placenta after the first trimester, is a specific glycoprotein that displays
dual luteinizing hormone (LH)-like and follicle-stimulating hormone (FSH)-like
effects in non-equid species. However, in equidaes, eCG exhibits only LH-like
activity. To identify the specific biological functions of glycosylated sites in
eCG, we constructed the following site mutants of N- and O-linked glycosylation:
eCGβ/αΔ56, substitution of α-subunit56
N-linked glycosylation site; eCGβ-D/α, deletion of the O-linked
glycosylation sites at the β-subunit, and
eCGβ-D/αΔ56, double mutant. We produced recombinant eCG
(rec-eCG) proteins in Chinese hamster ovary suspension (CHO-S) cells. We
examined the biological activity of rec-eCG proteins in CHO-K1 cells expressing
the eLH/CG receptor and found that signal transduction activities of
deglycosylated mutants remarkably decreased. The EC50 levels of
eCGβ/αΔ56, eCGβ-D/α, and
eCGβ-D/αΔ56 mutants decreased by 2.1-, 5.6-, and 3.4-fold,
respectively, compared to that of wild-type eCG. The Rmax values of the mutants
were 56%-80% those of wild-type eCG (141.9 nmol/104 cells). Our
results indicate that the biological activity of eCG is greatly affected by the
removal of N- and O-linked glycosylation sites in cells expressing eLH/CGR.
These results provide important information on rec-eCG in the regulation of
specific glycosylation sites and improve our understanding of the specific
biological activity of rec-eCG glycosylation sites in equidaes.
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Affiliation(s)
| | - Seung-Hee Choi
- Animal Biotechnology, Hankyong National University, Ansung 17579, Korea
| | - Hyo-Eun Joo
- Dept. of Animal Life Science, Hankyong National University, Ansung 17579, Korea
| | - Sang-Gwon Kim
- Dept. of Animal Life Science, Hankyong National University, Ansung 17579, Korea
| | - Yean-Ji Kim
- Dept. of Animal Life Science, Hankyong National University, Ansung 17579, Korea
| | - Gyeong-Eun Park
- Dept. of Animal Life Science, Hankyong National University, Ansung 17579, Korea
| | - Myung-Hwa Kang
- Dept. of Food Science and Nutrition, Hoseo University, Asan 31499, Korea
| | - Kwan-Sik Min
- Institute of Genetic Engineering, Hankyong National University, Ansung 17579, Korea.,Animal Biotechnology, Hankyong National University, Ansung 17579, Korea.,Dept. of Animal Life Science, Hankyong National University, Ansung 17579, Korea
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5
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Banerjee AA, Joseph S, Mahale SD. From cell surface to signalling and back: the life of the mammalian FSH receptor. FEBS J 2020; 288:2673-2696. [DOI: 10.1111/febs.15649] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 11/17/2020] [Accepted: 11/26/2020] [Indexed: 12/12/2022]
Affiliation(s)
- Antara A. Banerjee
- Division of Structural Biology National Institute for Research in Reproductive Health (Indian Council of Medical Research) Parel India
| | - Shaini Joseph
- Genetic Research Center National Institute for Research in Reproductive Health (Indian Council of Medical Research) Parel India
| | - Smita D. Mahale
- Division of Structural Biology National Institute for Research in Reproductive Health (Indian Council of Medical Research) Parel India
- ICMR Biomedical Informatics Centre National Institute for Research in Reproductive Health (Indian Council of Medical Research) Parel India
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6
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Olsen C, Memarzadeh K, Ulu A, Carr HS, Bean AJ, Frost JA. Regulation of Somatostatin Receptor 2 Trafficking by C-Tail Motifs and the Retromer. Endocrinology 2019; 160:1031-1043. [PMID: 30822353 PMCID: PMC6462214 DOI: 10.1210/en.2018-00865] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 02/25/2019] [Indexed: 12/15/2022]
Abstract
The Gi-coupled somatostatin receptor 2 (SST2) is a G protein-coupled receptor (GPCR) that mediates many of somatostatin's neuroendocrine actions. Upon stimulation, SST2 is rapidly internalized and transported to early endosomes before being recycled to the plasma membrane. However, little is known about the intracellular itinerary of SST2 after it moves to the early endosomal compartment or the cytoplasmic proteins that regulate its trafficking. As postsynaptic density protein/discs large 1/zonula occludens-1 (PDZ) domain interactions often regulate the trafficking and signaling potential of GPCRs, we examined the role of the SST2 PDZ ligand and additional C-terminal residues in controlling its intracellular trafficking. We determined that SST2 can recycle to the plasma membrane via multiple pathways, including a LAMP1/Rab7-positive late endosome to the trans-Golgi network (TGN) pathway. Trafficking from the late endosome to the TGN is often regulated by the retromer complex of endosomal coat proteins, and disrupting the retromer components sorting nexins 1/2 inhibits the budding of SST2 from late endosomes. Moreover, trafficking through the late endosomal/TGN pathway is dependent on an intact PDZ ligand and C-terminal tail, as truncating either the 3 or 10 C-terminal amino acids of SST2 alters the pathway through which it recycles to the plasma membrane. Moreover, addition of these amino acids to a heterologous receptor is sufficient to redirect it from a degradation pathway to a recycling itinerary. Our results demonstrate that endosomal trafficking of SST2 is dependent on numerous regulatory mechanisms controlled by its C terminus and the retromer machinery.
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Affiliation(s)
- Courtney Olsen
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, Texas
- MD Anderson UTHealth Graduate School of Biomedical Sciences, Houston, Texas
| | - Kimiya Memarzadeh
- MD Anderson UTHealth Graduate School of Biomedical Sciences, Houston, Texas
- Department of Neurobiology and Anatomy, University of Texas Health Science Center at Houston, Houston, Texas
| | - Arzu Ulu
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, Texas
| | - Heather S Carr
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, Texas
| | - Andrew J Bean
- MD Anderson UTHealth Graduate School of Biomedical Sciences, Houston, Texas
- Department of Neurobiology and Anatomy, University of Texas Health Science Center at Houston, Houston, Texas
- Department of Pediatrics, University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Jeffrey A Frost
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, Texas
- MD Anderson UTHealth Graduate School of Biomedical Sciences, Houston, Texas
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7
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Kim JM, Byambaragchaa M, Kang MH, Min KS. The C-terminal Phosphorylation Sites of eel Follicle-Stimulating Hormone Receptor are Important Role in the Signal Transduction. Dev Reprod 2018; 22:143-153. [PMID: 30023464 PMCID: PMC6048309 DOI: 10.12717/dr.2018.22.2.143] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Revised: 06/14/2018] [Accepted: 06/22/2018] [Indexed: 11/17/2022]
Abstract
The large extracellular domain of glycoprotein hormone receptors is a unique feature within the G protein-coupled receptors (GPCRs) family. After interaction with the hormone, the receptor becomes coupled to Gs, which, in turn stimulates adenylyl cyclase and the production of cAMP. Potential phosphorylation sites exist in the C-terminal region of GPCRs. The experiments described herein represent attempts to determine the functions of the eel follicle-stimulating hormone receptor (eelFSHR). We constructed a mutant of eelFSHR, in which the C-terminal cytoplasmic tail was truncated at residue 614 (eelFSHR-t614). The eelFSHR-t614 lacked all potential phosphorylation sites present in the C-terminal region of eelFSHR. In order to obtain the eelFSHR ligand, we produced recombinant follicle-stimulating hormone (rec-eelFSHβ/α) in the CHO-suspension cells. The expression level was 2-3 times higher than that of the transient expression of eelFSH in attached CHO-K1 cells. The molecular weight of the rec-eelFSHβ/α protein was identified to be approximately 34 kDa. The cells expressing eelFSHR-t614 showed an increase in agonist-induced cAMP responsiveness. The maximal cAMP responses of cells expressing eelFSHR-t614 were lower than those of cells expressing eelFSHR-wild type (eelFSHR-WT). The EC50 following C-terminal deletion in CHO-K1 cells was approximately 60.4% of that of eelFSHR-WT. The maximal response in eelFSHR-t614 cells was also drastically lower than that of eelFSHR-WT. We also found similar results in PathHunter Parental cells expressing β-arrestin. Thus, these data provide evidence that the truncation of the C-terminal cytoplasmic tail phosphorylation sites in the eelFSHR greatly decreased cAMP responsiveness and maximal response in both CHO-K1 cells and PathHunter Parental cells expressing β-arrestin.
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Affiliation(s)
- Jeong-Min Kim
- Animal Biotechnology, Graduate School of Future Convergence Technology, Dept. of Animal Life Science, Institute of Genetic Engineering, Hankyong National University, Ansung 17579, Korea
| | - Munkhzaya Byambaragchaa
- Animal Biotechnology, Graduate School of Future Convergence Technology, Dept. of Animal Life Science, Institute of Genetic Engineering, Hankyong National University, Ansung 17579, Korea
| | - Myung-Hwa Kang
- Dept. of Food Science and Nutrition, Hoseo University, Asan 31499, Korea
| | - Kwan-Sik Min
- Animal Biotechnology, Graduate School of Future Convergence Technology, Dept. of Animal Life Science, Institute of Genetic Engineering, Hankyong National University, Ansung 17579, Korea
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8
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Hanyaloglu AC. Advances in Membrane Trafficking and Endosomal Signaling of G Protein-Coupled Receptors. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 339:93-131. [PMID: 29776606 DOI: 10.1016/bs.ircmb.2018.03.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The integration of GPCR signaling with membrane trafficking, as a single orchestrated system, is a theme increasingly evident with the growing reports of GPCR endosomal signaling. Once viewed as a mechanism to regulate cell surface heterotrimeric G protein signaling, the endocytic trafficking system is complex, highly compartmentalized, yet deeply interconnected with cell signaling. The organization of receptors into distinct plasma membrane signalosomes, biochemically distinct endosomal populations, endosomal microdomains, and its communication with distinct subcellular organelles such as the Golgi provides multiple unique signaling platforms that are critical for specifying receptor function physiologically and pathophysiologically. In this chapter I discuss our emerging understanding in the endocytic trafficking systems employed by GPCRs and their novel roles in spatial control of signaling. Given the extensive roles that GPCRs play in vivo, these evolving models are starting to provide mechanistic understanding of distinct diseases and provide novel therapeutic avenues that are proving to be viable targets.
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Affiliation(s)
- Aylin C Hanyaloglu
- Institute of Reproductive and Developmental Biology, Department of Surgery and Cancer, Imperial College London, London, United Kingdom.
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9
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Ulloa-Aguirre A, Zariñán T, Gutiérrez-Sagal R, Dias JA. Intracellular Trafficking of Gonadotropin Receptors in Health and Disease. Handb Exp Pharmacol 2018; 245:1-39. [PMID: 29063275 DOI: 10.1007/164_2017_49] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Gonadotropin receptors belong to the highly conserved subfamily of the G protein-coupled receptor (GPCR) superfamily, the so-called Rhodopsin-like family (class A), which is the largest class of GPCRs and currently a major drug target. Both the follicle-stimulating hormone receptor (FSHR) and the luteinizing hormone/chorionic gonadotropin hormone receptor (LHCGR) are mainly located in the gonads where they play key functions associated to essential reproductive functions. As any other protein, gonadotropin receptors must be properly folded into a mature tertiary conformation compatible with quaternary assembly and endoplasmic reticulum export to the cell surface plasma membrane. Several primary and secondary structural features, including presence of particular amino acid residues and short motifs and in addition, posttranslational modifications, regulate intracellular trafficking of gonadotropin receptors to the plasma membrane as well as internalization and recycling of the receptor back to the cell surface after activation by agonist. Inactivating mutations of gonadotropin receptors may derive from receptor misfolding and lead to absent or reduced plasma membrane expression of the altered receptor, thereby manifesting an array of phenotypical abnormalities mostly characterized by reproductive failure and/or abnormal or absence of development of secondary sex characteristics. In this chapter we review the structural requirements necessary for intracellular trafficking of the gonadotropin receptors, and describe how mutations in these receptors may lead to receptor misfolding and disease in humans.
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Affiliation(s)
- Alfredo Ulloa-Aguirre
- Red de Apoyo a la Investigación (RAI), Universidad Nacional Autónoma de México-Instituto Nacional de Ciencias Médicas y Nutrición SZ, Vasco de Quiroga 15, Tlalpan, Mexico City, 14000, Mexico.
| | - Teresa Zariñán
- Red de Apoyo a la Investigación (RAI), Universidad Nacional Autónoma de México-Instituto Nacional de Ciencias Médicas y Nutrición SZ, Vasco de Quiroga 15, Tlalpan, Mexico City, 14000, Mexico
| | - Rubén Gutiérrez-Sagal
- Red de Apoyo a la Investigación (RAI), Universidad Nacional Autónoma de México-Instituto Nacional de Ciencias Médicas y Nutrición SZ, Vasco de Quiroga 15, Tlalpan, Mexico City, 14000, Mexico
| | - James A Dias
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY, USA
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10
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Evolving View of Membrane Trafficking and Signaling Systems for G Protein-Coupled Receptors. ENDOCYTOSIS AND SIGNALING 2018; 57:273-299. [DOI: 10.1007/978-3-319-96704-2_10] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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11
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Spatial encryption of G protein-coupled receptor signaling in endosomes; Mechanisms and applications. Biochem Pharmacol 2017; 143:1-9. [DOI: 10.1016/j.bcp.2017.04.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 04/25/2017] [Indexed: 01/14/2023]
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12
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Jean-Alphonse F, Bowersox S, Chen S, Beard G, Puthenveedu MA, Hanyaloglu AC. Spatially restricted G protein-coupled receptor activity via divergent endocytic compartments. J Biol Chem 2013; 289:3960-77. [PMID: 24375413 PMCID: PMC3924264 DOI: 10.1074/jbc.m113.526350] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Postendocytic sorting of G protein-coupled receptors (GPCRs) is driven by their interactions between highly diverse receptor sequence motifs with their interacting proteins, such as postsynaptic density protein (PSD95), Drosophila disc large tumor suppressor (Dlg1), zonula occludens-1 protein (zo-1) (PDZ) domain proteins. However, whether these diverse interactions provide an underlying functional specificity, in addition to driving sorting, is unknown. Here we identify GPCRs that recycle via distinct PDZ ligand/PDZ protein pairs that exploit their recycling machinery primarily for targeted endosomal localization and signaling specificity. The luteinizing hormone receptor (LHR) and β2-adrenergic receptor (B2AR), two GPCRs sorted to the regulated recycling pathway, underwent divergent trafficking to distinct endosomal compartments. Unlike B2AR, which traffics to early endosomes (EE), LHR internalizes to distinct pre-early endosomes (pre-EEs) for its recycling. Pre-EE localization required interactions of the LHR C-terminal tail with the PDZ protein GAIP-interacting protein C terminus, inhibiting its traffic to EEs. Rerouting the LHR to EEs, or EE-localized GPCRs to pre-EEs, spatially reprograms MAPK signaling. Furthermore, LHR-mediated activation of MAPK signaling requires internalization and is maintained upon loss of the EE compartment. We propose that combinatorial specificity between GPCR sorting sequences and interacting proteins dictates an unprecedented spatiotemporal control in GPCR signal activity.
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Affiliation(s)
- Frederic Jean-Alphonse
- From the Institute of Reproductive and Developmental Biology, Department of Surgery and Cancer, Imperial College London, London W12 0NN, United Kingdom and
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13
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HMGA2 inhibits apoptosis through interaction with ATR-CHK1 signaling complex in human cancer cells. Neoplasia 2013; 15:263-80. [PMID: 23479505 DOI: 10.1593/neo.121988] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 01/15/2013] [Accepted: 01/18/2013] [Indexed: 02/08/2023] Open
Abstract
The non-histone chromatin binding protein high mobility group AT-hook 2 (HMGA2) is expressed in stem cells and many cancer cells, including tumor initiating cells, but not translated in normal human somatic cells. The presence of HMGA2 is correlated with advanced neoplastic disease and poor prognosis for patients. We had previously demonstrated a role of HMGA2 in DNA repair pathways. In the present study, we employed different human tumor cell models with endogenous and exogenous expression of HMGA2 and show that upon DNA damage, the presence of HMGA2 caused an increased and sustained phosphorylation of the ataxia telangiectasia and Rad3-related kinase (ATR) and its downstream target checkpoint kinase 1 (CHK1). The presence of activated pCHK1(Ser296) coincided with prolonged G2/M block and increased tumor cell survival, which was enhanced further in the presence of HMGA2. Our study, thus, identifies a novel relationship between the ATR-CHK1 DNA damage response pathway and HMGA2, which may support the DNA repair function of HMGA2 in cancer cells. Furthermore, our data provide a rationale for the use of inhibitors to ATR or CHK1 and HMGA2 in the treatment of HMGA2-positive human cancer cells.
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14
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Gulappa T, Clouser CL, Menon KMJ. The role of Rab5a GTPase in endocytosis and post-endocytic trafficking of the hCG-human luteinizing hormone receptor complex. Cell Mol Life Sci 2011; 68:2785-95. [PMID: 21104291 PMCID: PMC4479136 DOI: 10.1007/s00018-010-0594-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 10/29/2010] [Accepted: 11/05/2010] [Indexed: 01/25/2023]
Abstract
This study examined the role of Rab5a GTPase in regulating hCG-induced internalization and trafficking of the hCG-LH receptor complex in transfected 293T cells. Coexpression of wild-type Rab5a (WT) or constitutively active Rab5a (Q79L) with LHR significantly increased hCG-induced LHR internalization. Conversely, coexpression of dominant negative Rab5a (S34N) with LHR reduced internalization. Confocal microscopy showed LHR colocalizing with Rab5a (WT) and Rab5a (Q79L) in punctuate structures. Coexpression of Rab5a (WT) and Rab5a (Q79L) with LHR significantly increased colocalization of LHR in early endosomes. Conversely, dominant negative Rab5a (S34N) decreased this colocalization. While Rab5a stimulated internalization of LHR, it significantly decreased LHR recycling to the cell surface and increased degradation. Dominant negative Rab5a (S34N) increased LHR recycling and decreased degradation. These results suggest that Rab5a plays a role in LHR trafficking by facilitating internalization and fusion to early endosomes, increasing the degradation of internalized receptor resulting in a reduction in LHR recycling.
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Affiliation(s)
- Thippeswamy Gulappa
- Departments of Obstetrics and Gynecology and Biological Chemistry, University of Michigan Medical School, University of Michigan, 6428 Medical Science I, 1301 Catherine Street, Ann Arbor, MI 48109-0617, USA
| | - Christine L. Clouser
- Departments of Obstetrics and Gynecology and Biological Chemistry, University of Michigan Medical School, University of Michigan, 6428 Medical Science I, 1301 Catherine Street, Ann Arbor, MI 48109-0617, USA
| | - K. M. J. Menon
- Departments of Obstetrics and Gynecology and Biological Chemistry, University of Michigan Medical School, University of Michigan, 6428 Medical Science I, 1301 Catherine Street, Ann Arbor, MI 48109-0617, USA
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Pandey KN. The functional genomics of guanylyl cyclase/natriuretic peptide receptor-A: perspectives and paradigms. FEBS J 2011; 278:1792-807. [PMID: 21375691 DOI: 10.1111/j.1742-4658.2011.08081.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The cardiac hormones atrial natriuretic peptide and B-type natriuretic peptide (brain natriuretic peptide) activate guanylyl cyclase (GC)-A/natriuretic peptide receptor-A (NPRA) and produce the second messenger cGMP. GC-A/NPRA is a member of the growing family of GC receptors. The recent biochemical, molecular and genomic studies on GC-A/NPRA have provided important insights into the regulation and functional activity of this receptor protein, with a particular emphasis on cardiac and renal protective roles in hypertension and cardiovascular disease states. The progress in this field of research has significantly strengthened and advanced our knowledge about the critical roles of Npr1 (coding for GC-A/NPRA) in the control of fluid volume, blood pressure, cardiac remodeling, and other physiological functions and pathological states. Overall, this review attempts to provide insights and to delineate the current concepts in the field of functional genomics and signaling of GC-A/NPRA in hypertension and cardiovascular disease states at the molecular level.
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Affiliation(s)
- Kailash N Pandey
- Department of Physiology, Tulane University Health Sciences Center School of Medicine, New Orleans, LA 70112, USA.
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16
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Huang SH, Zhao L, Sun ZP, Li XZ, Geng Z, Zhang KD, Chao MV, Chen ZY. Essential role of Hrs in endocytic recycling of full-length TrkB receptor but not its isoform TrkB.T1. J Biol Chem 2009; 284:15126-36. [PMID: 19351881 DOI: 10.1074/jbc.m809763200] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Brain-derived neurotrophic factor (BDNF) signaling through its receptor, TrkB, modulates survival, differentiation, and synaptic activity of neurons. Both full-length TrkB (TrkB-FL) and its isoform T1 (TrkB.T1) receptors are expressed in neurons; however, whether they follow the same endocytic pathway after BDNF treatment is not known. In this study we report that TrkB-FL and TrkB.T1 receptors traverse divergent endocytic pathways after binding to BDNF. We provide evidence that in neurons TrkB.T1 receptors predominantly recycle back to the cell surface by a "default" mechanism. However, endocytosed TrkB-FL receptors recycle to a lesser extent in a hepatocyte growth factor-regulated tyrosine kinase substrate (Hrs)-dependent manner which relies on its tyrosine kinase activity. The distinct role of Hrs in promoting recycling of internalized TrkB-FL receptors is independent of its ubiquitin-interacting motif. Moreover, Hrs-sensitive TrkB-FL recycling plays a role in BDNF-induced prolonged mitogen-activated protein kinase (MAPK) activation. These observations provide evidence for differential postendocytic sorting of TrkB-FL and TrkB.T1 receptors to alternate intracellular pathways.
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Affiliation(s)
- Shu-Hong Huang
- Department of Neurobiology, Key Laboratory of Medical Neurobiology, School of Medicine, Jinan, Shandong 250012, China
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17
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Lin CCJ, Clouser C, Peegel H, Menon B, Menon KMJ. The extracellular domain of luteinizing hormone receptor dictates its efficiency of maturation. Biochem Biophys Res Commun 2008; 377:307-11. [PMID: 18848524 DOI: 10.1016/j.bbrc.2008.09.136] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Accepted: 09/30/2008] [Indexed: 10/21/2022]
Abstract
The processing of luteinizing hormone receptor (LHR) shows marked differences in different species. While the human LHR is predominantly expressed as the mature, 90kDa species, rat LHR exists mostly in the 70kDa precursor form. Since the extracellular domain of the LHR is unusually large in comparison with other G protein-coupled receptors, the present studies examined the role of extracellular domain in its processing. FLAG-tagged chimeric LH receptors were constructed by substituting the extracellular domain of the human receptor in rat LHR (hrr) and the extracellular domain of the rat receptor in human LHR (rhh). The intracellular processing, ligand binding and recycling of the chimeric receptors were compared with that of the wild type receptors in 293T cells. The results showed that the human and rat LHR were expressed predominantly as 90 and 70kDa species, respectively, as expected. The introduction of the rat extracellular domain into the human LHR (rhh) decreased the abundance of the mature form with an increase in the precursor form. Conversely, substitution of the extracellular domain of the rat LHR by the extracellular domain of the human LHR (hrr) led to an increase in the mature form with a corresponding decrease in the precursor form. Changes were also observed in the ligand binding and recycling of the wild type and chimeric receptors. These results suggest that the extracellular domain of the LHR is one of the determinants that confer its ability for proper maturation and cell surface expression.
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Affiliation(s)
- Cindy Chan Juan Lin
- Departments of Biological Chemistry and Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI 48109-0617, USA
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18
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Hanyaloglu AC, von Zastrow M. Regulation of GPCRs by endocytic membrane trafficking and its potential implications. Annu Rev Pharmacol Toxicol 2008; 48:537-68. [PMID: 18184106 DOI: 10.1146/annurev.pharmtox.48.113006.094830] [Citation(s) in RCA: 447] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The endocytic pathway tightly controls the activity of G protein-coupled receptors (GPCRs). Ligand-induced endocytosis can drive receptors into divergent lysosomal and recycling pathways, producing essentially opposite effects on the strength and duration of cellular signaling via heterotrimeric G proteins, and may also promote distinct signaling events from intracellular membranes. This chapter reviews recent developments toward understanding the molecular machinery and functional implications of GPCR sorting in the endocytic pathway, focusing on mammalian GPCRs whose ligand-induced endocytosis is mediated primarily by clathrin-coated pits. Lysosomal sorting of a number of GPCRs occurs via a highly conserved mechanism requiring covalent tagging of receptors with ubiquitin. There is increasing evidence that additional, noncovalent mechanisms control the sorting of endocytosed GPCRs to lysosomes in mammalian cells. Recycling of several GPCRs to the plasma membrane is also specifically sorted, via a mechanism requiring both receptor-specific and shared sorting proteins. The current data reveal an unprecedented degree of specificity and plasticity in the cellular regulation of mammalian GPCRs by endocytic membrane trafficking. These developments have fundamental implications for GPCR pharmacology, and suggest new mechanisms that could be exploited in GPCR-directed pharmacotherapy.
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Affiliation(s)
- Aylin C Hanyaloglu
- Institute of Reproductive Biology and Development, Imperial College London, Hammersmith Campus, London, United Kingdom
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19
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Galet C, Ascoli M. A constitutively active mutant of the human lutropin receptor (hLHR-L457R) escapes lysosomal targeting and degradation. Mol Endocrinol 2006; 20:2931-45. [PMID: 16803865 PMCID: PMC1626098 DOI: 10.1210/me.2006-0138] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Using biochemical and imaging approaches, we examined the postendocytotic fate of the complex formed by human choriogonadotropin (hCG) and a constitutively active mutant of the human lutropin receptor (hLHR-L457R) found in a boy with precocious puberty and Leydig cell hyperplasia. After internalization, some of the complex formed by the hLHR-wild type (hLHR-wt) and hCG recycles to the cell surface, and some is found in lysosomes where the hormone is degraded. In contrast, the complex formed by the hLHR-L457R and hCG is not routed to the lysosomes, most of it is recycled to the cell surface and hormone degradation is barely detectable. For both, hLHR-wt and -L457R, there is an hCG-induced loss of cell surface receptors that accompanies internalization but this loss cannot be prevented by leupeptin. The removal of recycling motifs of the hLHR by truncation of the C-terminal tail at residue 682 greatly enhances the lysosomal accumulation of the hormone-receptor complexes formed by the hLHR-wt or the L457R mutant, the degradation of the internalized hormone, and the loss of cell surface receptors. The degradation of the hormone internalized by these mutants as well as the loss of cell surface receptors is largely prevented by leupeptin. These results highlight a previously unrecognized complexity in the postendocytotic trafficking of the hLHR and document a clear difference between the properties of the constitutively active mutant and the agonist-activated hLHR-wt. This lack of lysosomal degradation of the L457R mutant could contribute to its constitutive activity by prolonging the duration of signaling.
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Affiliation(s)
- Colette Galet
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, 2-319B Bowen Science Building, 51 Newton Road, Iowa City, Iowa 52242-1109, USA
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20
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Hamelin E, Thériault C, Laroche G, Parent JL. The Intracellular Trafficking of the G Protein-coupled Receptor TPβ Depends on a Direct Interaction with Rab11. J Biol Chem 2005; 280:36195-205. [PMID: 16126723 DOI: 10.1074/jbc.m503438200] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Intracellular trafficking pathways of cell surface receptors following their internalization are the subject of intense research efforts. However, the mechanisms by which they recycle back to the cell surface are still poorly defined. We have recently demonstrated that the small Rab11 GTPase protein is a determinant factor in controlling the recycling to the cell surface of the beta-isoform of the thromboxane A2 receptor (TPbeta) following its internalization. Here, we demonstrate with co-immunoprecipitation studies in HEK293 cells that there is a Rab11-TPbeta association occurring in the absence of agonist, which is not modulated by stimulation of TPbeta. We show with purified TPbeta intracellular domains fused to GST and HIS-Rab11 proteins that Rab11 interacts directly with the first intracellular loop and the C-tail of TPbeta. Amino acids 335-344 of the TPbeta C-tail were determined to be essential for the interaction of Rab11 with this receptor domain. This identified sequence appears to be important in directing the intracellular trafficking of the receptor from the Rab5-positive intracellular compartment to the perinuclear recycling endosome. Interestingly, our data indicate that TPbeta interacts with the GDP-bound form, and not the GTP-bound form, of Rab11 which is necessary for recycling of the receptor back to the cell surface. To our knowledge, this is the first demonstration of a direct interaction between Rab11 and a transmembrane receptor.
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Affiliation(s)
- Emilie Hamelin
- Service de Rhumatologie, Faculté de Médecine and Centre de Recherche Clinique-CHUS, Université de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
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21
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Hanyaloglu AC, McCullagh E, von Zastrow M. Essential role of Hrs in a recycling mechanism mediating functional resensitization of cell signaling. EMBO J 2005; 24:2265-83. [PMID: 15944737 PMCID: PMC1173141 DOI: 10.1038/sj.emboj.7600688] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2004] [Accepted: 04/28/2005] [Indexed: 12/13/2022] Open
Abstract
Hepatocyte growth factor-regulated tyrosine kinase substrate (Hrs) is well known to terminate cell signaling by sorting activated receptors to the MVB/lysosomal pathway. Here we identify a distinct role of Hrs in promoting rapid recycling of endocytosed signaling receptors to the plasma membrane. This function of Hrs is specific for receptors that recycle in a sequence-directed manner, in contrast to default recycling by bulk membrane flow, and is distinguishable in several ways from previously identified membrane-trafficking functions of Hrs/Vps27p. In particular, Hrs function in sequence-directed recycling does not require other mammalian Class E gene products involved in MVB/lysosomal sorting, nor is receptor ubiquitination required. Mutational studies suggest that the VHS domain of Hrs plays an important role in sequence-directed recycling. Disrupting Hrs-dependent recycling prevented functional resensitization of the beta(2)-adrenergic receptor, converting the temporal profile of cell signaling by this prototypic G protein-coupled receptor from sustained to transient. These studies identify a novel function of Hrs in a cargo-specific recycling mechanism, which is critical to controlling functional activity of the largest known family of signaling receptors.
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MESH Headings
- ATPases Associated with Diverse Cellular Activities
- Adenosine Triphosphatases/metabolism
- Adrenergic beta-2 Receptor Agonists
- Adrenergic beta-2 Receptor Antagonists
- Cell Membrane/metabolism
- DNA-Binding Proteins/metabolism
- Endocytosis/physiology
- Endosomal Sorting Complexes Required for Transport
- HeLa Cells
- Humans
- Membrane Proteins/metabolism
- Mutation
- Phosphoproteins/genetics
- Phosphoproteins/metabolism
- Protein Sorting Signals
- Protein Structure, Tertiary
- Receptors, Adrenergic, beta-2/metabolism
- Receptors, G-Protein-Coupled/metabolism
- Receptors, Opioid, mu/agonists
- Receptors, Opioid, mu/antagonists & inhibitors
- Receptors, Opioid, mu/metabolism
- Repressor Proteins/metabolism
- Signal Transduction/physiology
- Transcription Factors/metabolism
- Vacuolar Proton-Translocating ATPases
- Vesicular Transport Proteins
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Affiliation(s)
| | | | - Mark von Zastrow
- University of California, San Francisco, CA, USA
- Department of Psychiatry and Department of Cellular and Molecular Pharmacology, UCSF, N212 Genentech Hall, San Francisco, CA 94143-2140, USA. Tel.: +1 415 476 7855; Fax: +1 415 514 0169; E-mail:
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22
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Menon KMJ, Clouser CL, Nair AK. Gonadotropin receptors: role of post-translational modifications and post-transcriptional regulation. Endocrine 2005; 26:249-57. [PMID: 16034179 DOI: 10.1385/endo:26:3:249] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2005] [Accepted: 05/02/2005] [Indexed: 11/11/2022]
Abstract
This review focuses on the post-translational modifications of LH and FSH receptors and recent studies on the regulation of LH receptor expression mediated by an RNA binding protein. Both LH and FSH receptors undergo extensive post-translational modifications. N-linked glycosylation occurs co-translationally and plays a role in the maturation and processing of the receptor, while palmitoylation is involved in receptor endocytosis and post-endocytic trafficking. A third type of post-translational modification is phosphorylation and its function has been reviewed. Finally, the regulation of LH receptor at the mRNA level by an RNA binding protein is discussed in the context of ovarian function.
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Affiliation(s)
- K M J Menon
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, 48109-0617, USA.
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23
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Munshi UM, Clouser CL, Peegel H, Menon KMJ. Evidence that palmitoylation of carboxyl terminus cysteine residues of the human luteinizing hormone receptor regulates postendocytic processing. Mol Endocrinol 2005; 19:749-58. [PMID: 15539429 DOI: 10.1210/me.2004-0335] [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
Palmitoylation is a well-conserved posttranslational modification among members of the G protein-coupled receptor superfamily. The present study examined the role of palmitoylation in endocytosis and postendocytic trafficking of the human LH receptor (LHR). Palmitoylation of the LHR was determined by incorporation of [3H]palmitic acid into wild-type (WT) or mutant receptor in which the potential palmitoylation sites, C643 and C644, were mutated to glycine residues. The WT receptor showed incorporation of [3H]palmitic acid into the mature 90-kDa form of the receptor whereas mutation of the two Cys residues abrogated this incorporation, indicating that Cys 643 and C644 are the sites of palmitoylation. The role of palmitoylation on endocytosis and postendocytic processing was examined by testing the ability of the WT and mutant receptor to undergo internalization, recycling, and lysosomal degradation. Compared with the WT receptor, the mutant receptor showed increased internalization and decreased recycling, suggesting that retention of palmitic acid residues at Cys 643 and 644 promotes LHR recycling. The role of palmitoylation on receptor recycling was substantiated by demonstrating that a different mutant, D578H LHR, which is deficient in palmitoylation, also recycled less efficiently. Furthermore, the data show that palmitoylation, not the rate of internalization, determines the efficiency of recycling. The present study shows that palmitoylation of cysteine residues 643 and 644 of the human LHR is a determinant of recycling.
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Affiliation(s)
- Utpal M Munshi
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109-0617, USA
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24
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Horio S, Kato T, Ogawa M, Fujimoto K, Fukui H. Two threonine residues and two serine residues in the second and third intracellular loops are both involved in histamine H1receptor downregulation. FEBS Lett 2004; 573:226-30. [PMID: 15328002 DOI: 10.1016/j.febslet.2004.07.072] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2004] [Revised: 07/04/2004] [Accepted: 07/05/2004] [Indexed: 11/24/2022]
Abstract
Human histamine H1 receptor (H1R) contains five possible phosphorylation residues (Thr140, Thr142, Ser396, Ser398 and Thr478) and the substitution of all these five residues to alanine completely impairs agonist-induced receptor downregulation. In the present study, to determine which residue(s) are responsible for receptor downregulation, we used mutant H1Rs in which single or multiple residues were substituted with alanine. The results suggested that two groups, i.e., residues Thr140 and Thr142, and residues Ser396 and Ser398, independently contributed to H1R downregulation. Thr140 and Ser398 mainly contributed to downregulation, and Thr142 or Ser396 had a slight inhibitory effect on Thr140- or Ser398-mediated process, respectively.
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Affiliation(s)
- Shuhei Horio
- Department of Molecular Pharmacology, Division of Pharmaceutical Sciences, Graduate School of Health and Bioscience, the University of Tokushima, 1-78-1 Shomachi, Tokushima 770-8505, Japan
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25
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Vargas GA, Von Zastrow M. Identification of a novel endocytic recycling signal in the D1 dopamine receptor. J Biol Chem 2004; 279:37461-9. [PMID: 15192107 DOI: 10.1074/jbc.m401034200] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A critical event determining the functional consequences of G protein-coupled receptor (GPCR) endocytosis is the molecular sorting of internalized receptors between divergent recycling and degradative membrane pathways. The D1 dopamine receptor recycles rapidly and efficiently to the plasma membrane after agonist-induced endocytosis and is remarkably resistant to proteolytic down-regulation. Whereas the mechanism mediating agonist-induced endocytosis of D1 receptors has been investigated in some detail, little is known about how receptors are sorted after endocytosis. We have identified a sequence present in the carboxyl-terminal cytoplasmic domain of the human D1 dopamine receptor that is specifically required for the efficient recycling of endocytosed receptors back to the plasma membrane. This sequence is distinct from previously identified membrane trafficking signals and is located in a proximal portion of the carboxyl-terminal cytoplasmic domain, in contrast to previously identified GPCR recycling signals present at the distal tip. Nevertheless, fusion of this sequence to the carboxyl terminus of a chimeric mutant delta opioid neuropeptide receptor is sufficient to re-route internalized receptors from lysosomal to recycling membrane pathways, defining this sequence as a bona fide endocytic recycling signal that can function in both proximal and distal locations. These results identify a novel sorting signal controlling the endocytic trafficking itinerary of a physiologically important dopamine receptor, provide the first example of such a sorting signal functioning in a proximal portion of the carboxyl-terminal cytoplasmic domain, and suggest the existence of a diverse array of sorting signals in the GPCR superfamily that mediate subtype-specific regulation of receptors via endocytic membrane trafficking.
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Affiliation(s)
- Gabriel A Vargas
- Departments of Psychiatry and Cellular and Molecular Pharmacology, University of California, San Francisco, California 94143-2140, USA.
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26
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Tanowitz M, von Zastrow M. A novel endocytic recycling signal that distinguishes the membrane trafficking of naturally occurring opioid receptors. J Biol Chem 2003; 278:45978-86. [PMID: 12939277 DOI: 10.1074/jbc.m304504200] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
delta and micro opioid receptors are homologous G protein-coupled receptors that are differentially sorted between divergent degradative and recycling membrane pathways following agonist-induced endocytosis. Whereas delta opioid receptors are selectively sorted to lysosomes, micro opioid receptors recycle rapidly to the plasma membrane by a process that has been proposed to occur via bulk membrane flow. We have observed that micro opioid receptors do not recycle by default and have defined a specific sequence present in the cytoplasmic tail of the cloned micro opioid receptor that is both necessary and sufficient for rapid recycling of internalized receptors. This sequence is completely distinct from a sequence shown previously to be required for recycling of the beta2 adrenergic receptor yet is functionally interchangeable when tested in chimeric mutant receptors. These results indicate that signal-dependent recycling is a more common property of G protein-coupled receptors than previously appreciated and demonstrate that such a modular recycling signal distinguishes the regulation of homologous receptors that are naturally co-expressed.
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Affiliation(s)
- Michael Tanowitz
- Departments of Psychiatry and Cellular & Molecular Pharmacology, University of California, San Francisco, California 94143-2140, USA.
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27
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Krishnamurthy H, Kishi H, Shi M, Galet C, Bhaskaran RS, Hirakawa T, Ascoli M. Postendocytotic trafficking of the follicle-stimulating hormone (FSH)-FSH receptor complex. Mol Endocrinol 2003; 17:2162-76. [PMID: 12907758 DOI: 10.1210/me.2003-0118] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Although the fates of the internalized hormone-receptor complexes formed by the lutropin/choriogonadotropin and the TSH receptors have been examined in some detail, much less is known about the fate of the internalized FSH-FSH receptor (FSHR) complex. Using biochemical and imaging approaches we show here that the majority of the internalized FSH-FSHR complex accumulates in endosomes and subsequently recycles back to the cell surface where the bound, intact hormone dissociates back into the medium. Only small amounts of FSH and the FSHR are routed to a lysosomal degradation pathway, and the extent of FSH-induced down-regulation of the cell surface and total FSHR is minimal. This pathway was detected in heterologous (human kidney 293T) cells transfected with the rat (r) or human (h) FSHR as well as in a mouse Sertoli cell line (MSC-1) or a mouse granulosa cell line (KK-1) transfected with the rFSHR.Additional experiments using a series of C-terminal deletions of the rFSHR and the hFSHR showed that the recycling of the internalized FSH-FSHR complex and the extent of hFSH-induced down-regulation is dictated by a short stretch of amino acids present at the extreme C-terminal end of the receptor.We conclude that most of the internalized FSH-FSHR complex is recycled back to the cell surface, that this recycling pathway is highly dependent on amino acid residues present near the C terminus of the FSHR, and that it is an important determinant of the extent of down-regulation of the FSHR.
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28
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Hirakawa T, Galet C, Kishi M, Ascoli M. GIPC binds to the human lutropin receptor (hLHR) through an unusual PDZ domain binding motif, and it regulates the sorting of the internalized human choriogonadotropin and the density of cell surface hLHR. J Biol Chem 2003; 278:49348-57. [PMID: 14507927 DOI: 10.1074/jbc.m306557200] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
By using a yeast two-hybrid screen we identified GIPC (GAIP-interacting protein C terminus), a protein with a type I PDZ domain as a novel human lutropin receptor (hLHR) binding partner. Pull-down and immunoprecipitation assays confirmed this interaction and showed that it is dependent on the PDZ domain of GIPC and the C-terminal tetrapeptide of the hLHR. To characterize the functional consequences of the GIPC-hLHR interaction, we used a small interfering RNA against GIPC to generate a clonal cell line that is deficient in GIPC. Studies with this cell line reveal that GIPC is partially responsible for the recycling of the hormone that is internalized by the hLHR and also for maintaining a relatively constant level of hLHR at the cell surface during hormone internalization.
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Affiliation(s)
- Takashi Hirakawa
- Department of Pharmacology, the University of Iowa, Iowa City, Iowa 52242, USA
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