1
|
Ammonia induces amyloidogenesis in astrocytes by promoting amyloid precursor protein translocation into the endoplasmic reticulum. J Biol Chem 2022; 298:101933. [PMID: 35427648 PMCID: PMC9117890 DOI: 10.1016/j.jbc.2022.101933] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 03/26/2022] [Accepted: 03/26/2022] [Indexed: 11/25/2022] Open
Abstract
Hyperammonemia is known to cause various neurological dysfunctions such as seizures and cognitive impairment. Several studies have suggested that hyperammonemia may also be linked to the development of Alzheimer’s disease (AD). However, the direct evidence for a role of ammonia in the pathophysiology of AD remains to be discovered. Herein, we report that hyperammonemia increases the amount of mature amyloid precursor protein (mAPP) in astrocytes, the largest and most prevalent type of glial cells in the central nervous system that are capable of metabolizing glutamate and ammonia, and promotes amyloid beta (Aβ) production. We demonstrate the accumulation of mAPP in astrocytes was primarily due to enhanced endocytosis of mAPP from the plasma membrane. A large proportion of internalized mAPP was targeted not to the lysosome, but to the endoplasmic reticulum, where processing enzymes β-secretase BACE1 (beta-site APP cleaving enzyme 1) and γ-secretase presenilin-1 are expressed, and mAPP is cleaved to produce Aβ. Finally, we show the ammonia-induced production of Aβ in astrocytic endoplasmic reticulum was specific to Aβ42, a principal component of senile plaques in AD patients. Our studies uncover a novel mechanism of Aβ42 production in astrocytes and also provide the first evidence that ammonia induces the pathogenesis of AD by regulating astrocyte function.
Collapse
|
2
|
Ma CIJ, Burgess J, Brill JA. Maturing secretory granules: Where secretory and endocytic pathways converge. Adv Biol Regul 2021; 80:100807. [PMID: 33866198 DOI: 10.1016/j.jbior.2021.100807] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 03/10/2021] [Accepted: 03/18/2021] [Indexed: 10/21/2022]
Abstract
Secretory granules (SGs) are specialized organelles responsible for the storage and regulated release of various biologically active molecules from the endocrine and exocrine systems. Thus, proper SG biogenesis is critical to normal animal physiology. Biogenesis of SGs starts at the trans-Golgi network (TGN), where immature SGs (iSGs) bud off and undergo maturation before fusing with the plasma membrane (PM). How iSGs mature is unclear, but emerging studies have suggested an important role for the endocytic pathway. The requirement for endocytic machinery in SG maturation blurs the line between SGs and another class of secretory organelles called lysosome-related organelles (LROs). Therefore, it is important to re-evaluate the differences and similarities between SGs and LROs.
Collapse
Affiliation(s)
- Cheng-I Jonathan Ma
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, Room 15.9716, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada; Institute of Medical Science, University of Toronto, Medical Sciences Building, Room 2374, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada
| | - Jason Burgess
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, Room 15.9716, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada; Department of Molecular Genetics, University of Toronto, Medical Sciences Building, Room 4396, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada
| | - Julie A Brill
- Cell Biology Program, The Hospital for Sick Children, PGCRL Building, Room 15.9716, 686 Bay Street, Toronto, Ontario, M5G 0A4, Canada; Institute of Medical Science, University of Toronto, Medical Sciences Building, Room 2374, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada; Department of Molecular Genetics, University of Toronto, Medical Sciences Building, Room 4396, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada.
| |
Collapse
|
3
|
Wei Z, Zhang M, Li C, Huang W, Fan Y, Guo J, Khater M, Fukuda M, Dong Z, Hu G, Wu G. Specific TBC Domain-Containing Proteins Control the ER-Golgi-Plasma Membrane Trafficking of GPCRs. Cell Rep 2020; 28:554-566.e4. [PMID: 31291588 PMCID: PMC6639060 DOI: 10.1016/j.celrep.2019.05.033] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 11/14/2018] [Accepted: 05/09/2019] [Indexed: 12/13/2022] Open
Abstract
G-protein-coupled receptors (GPCRs) constitute the largest superfamily of cell surface signaling proteins. However, the molecular mechanisms underlying their cell surface delivery after synthesis remain poorly understood. Here, we screen the TBC domain-containing proteins, putative Rab GTPase-activating proteins (GAPs), in the intracellular trafficking of GPCRs and identify several TBC proteins that activity-dependently regulate the anterograde transport, en route from the endoplasmic reticulum to the Golgi or from the Golgi to the cell surface, of several prototypic GPCR members without affecting other plasma membrane proteins. We also show that TBC1D6 functions as a GAP for Rab26, physically associates with Rab26, and attenuates Rab26 interaction with GPCRs. Furthermore, both overexpression and depletion of TBC1D6 inhibit the post-Golgi traffic of GPCRs. These data demonstrate important roles of the TBC proteins in forward trafficking of nascent GPCRs and reveal regulatory mechanisms of GPCR targeting to the functional destination. Wei et al. report that several TBC proteins specifically and activity-dependently regulate ER-Golgi-plasma membrane transport of nascent GPCRs. They also show that TBC1D6 is a GAP for Rab26 and controls GPCR post-Golgi traffic. Their results reveal crucial roles of TBC proteins in and provide regulatory mechanisms of GPCR trafficking.
Collapse
Affiliation(s)
- Zhe Wei
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Maoxiang Zhang
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Chunman Li
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Wei Huang
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Yi Fan
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Jianhui Guo
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Mostafa Khater
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Mitsunori Fukuda
- Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Zheng Dong
- Department of Cell Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA; Charlie Norwood VA Medical Center, Augusta, GA 30904, USA
| | - Gang Hu
- Department of Pharmacology, Nanjing University of Chinese Medicine, Nanjing, China
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA.
| |
Collapse
|
4
|
Xu X, Wu G. Quantification of The Surface Expression of G Protein-coupled Receptors Using Intact Live-cell Radioligand Binding Assays. Bio Protoc 2020; 10:e3761. [PMID: 33628863 DOI: 10.21769/bioprotoc.3761] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
G protein-coupled receptors (GPCRs) are the most structurally diverse family of signaling proteins and regulate a variety of cell function. For most GPCRs, the cell surface is their functional destination where they are able to respond a wide range of extracellular stimuli, leading to the activation of intracellular signal transduction cascades. Thus, the quantity of receptor expression at the cell surface is a crucial factor regulating the functionality of the receptors. Over the past decades, many methods have been developed to measure the cell surface expression of GPCRs. Here, we describe an intact live-cell radioligand binding assay to quantify the surface expression of GPCRs at the endogenous levels or after overexpression. In this assay, cell cultures will be incubated with specific cell-nonpermeable radioligands which selectively and stoichiometrically bind to individual GPCRs and the receptor numbers at the cell surface are quantified by the radioactivity of receptor-bound ligands. This method is highly specific for measuring the functional GPCRs at the surface of intact live cells and is particularly useful for endogenous, low-abundant GPCRs.
Collapse
Affiliation(s)
- Xin Xu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| |
Collapse
|
5
|
Zhang M, Wu G. Mechanisms of the anterograde trafficking of GPCRs: Regulation of AT1R transport by interacting proteins and motifs. Traffic 2018; 20:110-120. [PMID: 30426616 DOI: 10.1111/tra.12624] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 10/29/2018] [Accepted: 11/08/2018] [Indexed: 12/11/2022]
Abstract
Anterograde cell surface transport of nascent G protein-coupled receptors (GPCRs) en route from the endoplasmic reticulum (ER) through the Golgi apparatus represents a crucial checkpoint to control the amount of the receptors at the functional destination and the strength of receptor activation-elicited cellular responses. However, as compared with extensively studied internalization and recycling processes, the molecular mechanisms of cell surface trafficking of GPCRs are relatively less defined. Here, we will review the current advances in understanding the ER-Golgi-cell surface transport of GPCRs and use angiotensin II type 1 receptor as a representative GPCR to discuss emerging roles of receptor-interacting proteins and specific motifs embedded within the receptors in controlling the forward traffic of GPCRs along the biosynthetic pathway.
Collapse
Affiliation(s)
- Maoxiang Zhang
- Guangzhou University of Chinese Medicine, Guangzhou, China.,Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia
| |
Collapse
|
6
|
Wang G, Wei Z, Wu G. Role of Rab GTPases in the export trafficking of G protein-coupled receptors. Small GTPases 2018; 9:130-135. [PMID: 28125329 PMCID: PMC5902197 DOI: 10.1080/21541248.2016.1277000] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 12/12/2016] [Accepted: 12/21/2016] [Indexed: 12/11/2022] Open
Abstract
G protein-coupled receptors (GPCRs) constitute a superfamily of cell surface receptors that regulate a variety of cell functions. As the cell surface is the functional destination for most GPCRs, the cell surface targeting process represents a crucial checkpoint in controlling the functionality of the receptors. However, the molecular mechanisms underlying the cell surface delivery of newly synthesized GPCRs remain poorly understood. In this review, we will highlight the role of Rab GTPases in GPCR cell surface transport, particularly post-Golgi traffic, and discuss the underlying molecular mechanisms.
Collapse
Affiliation(s)
- Guansong Wang
- Institute of Respiratory Diseases, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Zhe Wei
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| |
Collapse
|
7
|
Ueda N, Tomita T, Yanagisawa K, Kimura N. Retromer and Rab2-dependent trafficking mediate PS1 degradation by proteasomes in endocytic disturbance. J Neurochem 2016; 137:647-58. [PMID: 26896628 DOI: 10.1111/jnc.13586] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Revised: 01/21/2016] [Accepted: 02/09/2016] [Indexed: 12/21/2022]
Abstract
Accumulating evidence suggests that endocytic pathway deficits are involved in Alzheimer's disease pathogenesis. Several reports show that endocytic disturbance affects β-amyloid peptide (Aβ) cleavage from β-amyloid precursor protein (APP). Presenilin-1 (PS1) is the catalytic core of the γ-secretase complex required for Aβ generation. Previously, we showed that aging induces endocytic disturbance, resulting in the accumulation of Aβ and APP in enlarged endosomes. It remains unclear, however, whether PS1 localization and function are affected with endocytic disturbance. Here, we report that in endocytic disturbance, PS1 is transported from endosomes to ER/Golgi compartments via retromer trafficking, and that PS1 interacts with vacuolar protein sorting-associated protein 35 both in vitro and in vivo. Moreover, PS1 is degraded by proteasomes via a Rab2-dependent trafficking pathway, only during endocytic disturbance. These findings suggest that PS1 levels and localization in endosomes are regulated by retromer trafficking and ER-associated degradation system, even if endocytic disturbance significantly induces the endosomal accumulation of APP and β-site APP-cleaving enzyme 1. Results of this study also suggest that retromer deficiency can affect PS1 localization in endosomes, where Aβ cleavage mainly occurs, possibly leading to enhanced Aβ pathology. We proposed the following mechanism for intracellular transport of presenilin-1 (PS1). When endosome/lysosome trafficking is disturbed, PS1 is transported from endosome to endoplasmic reticulum (ER)/Golgi compartments via retromer and Rab2-mediated trafficking, and then degraded by endoplasmic reticulum-associated degradation (ERAD). Perturbations in this trafficking can cause abnormal endosomal accumulation of PS1, and then may lead to exacerbated Aβ pathology. Cover Image for this issue: doi: 10.1111/jnc.13318.
Collapse
Affiliation(s)
- Naoya Ueda
- Section of Cell Biology and Pathology, Department of Alzheimer's Disease Research, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology (NCGG), Aichi, Japan
| | - Taisuke Tomita
- Laboratory of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Katsuhiko Yanagisawa
- Section of Cell Biology and Pathology, Department of Alzheimer's Disease Research, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology (NCGG), Aichi, Japan
| | - Nobuyuki Kimura
- Section of Cell Biology and Pathology, Department of Alzheimer's Disease Research, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology (NCGG), Aichi, Japan
| |
Collapse
|
8
|
Lin Y, Xiang Z, He Y. Ontology-based representation and analysis of host-Brucella interactions. J Biomed Semantics 2015; 6:37. [PMID: 26445639 PMCID: PMC4594885 DOI: 10.1186/s13326-015-0036-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 09/23/2015] [Indexed: 11/26/2022] Open
Abstract
Background Biomedical ontologies are representations of classes of entities in the biomedical domain and how these classes are related in computer- and human-interpretable formats. Ontologies support data standardization and exchange and provide a basis for computer-assisted automated reasoning. IDOBRU is an ontology in the domain of Brucella and brucellosis. Brucella is a Gram-negative intracellular bacterium that causes brucellosis, the most common zoonotic disease in the world. In this study, IDOBRU is used as a platform to model and analyze how the hosts, especially host macrophages, interact with virulent Brucella strains or live attenuated Brucella vaccine strains. Such a study allows us to better integrate and understand intricate Brucella pathogenesis and host immunity mechanisms. Results Different levels of host-Brucella interactions based on different host cell types and Brucella strains were first defined ontologically. Three important processes of virulent Brucella interacting with host macrophages were represented: Brucella entry into macrophage, intracellular trafficking, and intracellular replication. Two Brucella pathogenesis mechanisms were ontologically represented: Brucella Type IV secretion system that supports intracellular trafficking and replication, and Brucella erythritol metabolism that participates in Brucella intracellular survival and pathogenesis. The host cell death pathway is critical to the outcome of host-Brucella interactions. For better survival and replication, virulent Brucella prevents macrophage cell death. However, live attenuated B. abortus vaccine strain RB51 induces caspase-2-mediated proinflammatory cell death. Brucella-associated cell death processes are represented in IDOBRU. The gene and protein information of 432 manually annotated Brucella virulence factors were represented using the Ontology of Genes and Genomes (OGG) and Protein Ontology (PRO), respectively. Seven inference rules were defined to capture the knowledge of host-Brucella interactions and implemented in IDOBRU. Current IDOBRU includes 3611 ontology terms. SPARQL queries identified many results that are critical to the host-Brucella interactions. For example, out of 269 protein virulence factors related to macrophage-Brucella interactions, 81 are critical to Brucella intracellular replication inside macrophages. A SPARQL query also identified 11 biological processes important for Brucella virulence. Conclusions To systematically represent and analyze fundamental host-pathogen interaction mechanisms, we provided for the first time comprehensive ontological modeling of host-pathogen interactions using Brucella as the pathogen model. The methods and ontology representations used in our study are generic and can be broadened to study the interactions between hosts and other pathogens. Electronic supplementary material The online version of this article (doi:10.1186/s13326-015-0036-y) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Yu Lin
- Unit of Laboratory Animal Medicine, Department of Microbiology and Immunology, Center for Computational Medicine and Bioinformatics, and Comprehensive Cancer Center, University of Michigan Medical School, 1150 W. Medical Center Dr, Ann Arbor, MI 48109 USA
| | - Zuoshuang Xiang
- Unit of Laboratory Animal Medicine, Department of Microbiology and Immunology, Center for Computational Medicine and Bioinformatics, and Comprehensive Cancer Center, University of Michigan Medical School, 1150 W. Medical Center Dr, Ann Arbor, MI 48109 USA
| | - Yongqun He
- Unit of Laboratory Animal Medicine, Department of Microbiology and Immunology, Center for Computational Medicine and Bioinformatics, and Comprehensive Cancer Center, University of Michigan Medical School, 1150 W. Medical Center Dr, Ann Arbor, MI 48109 USA
| |
Collapse
|
9
|
Zhu S, Zhang M, Davis JE, Wu WH, Surrao K, Wang H, Wu G. A single mutation in helix 8 enhances the angiotensin II type 1a receptor transport and signaling. Cell Signal 2015; 27:2371-9. [PMID: 26342563 DOI: 10.1016/j.cellsig.2015.08.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 08/30/2015] [Indexed: 01/01/2023]
Abstract
The amphipathic helix 8 in the membrane-proximal C-terminus is a structurally conserved feature of class A seven transmembrane-spanning G protein-coupled receptors (GPCRs). Mutations of this helical motif often cause receptor misfolding, defective cell surface transport and dysfunction. Surprisingly, we demonstrated here that a single point mutation at Lys308 in helix 8 markedly enhanced the steady-state surface density of the angiotensin II type 1a receptor (AT1aR). Consistent with the enhanced cell surface expression, Lys308 mutation significantly augmented AT1aR-mediated mitogen-activated protein kinase ERK1/2 activation, inositol phosphate production, and vascular smooth muscle cell migration. This mutation also increased the overall expression of AT1aR without altering receptor degradation. More interestingly, Lys308 mutation abolished AT1aR interaction with β-COP, a component of COPI transport vesicles, and impaired AT1aR responsiveness to the inhibition of Rab6 GTPase involved in the Golgi-to-ER retrograde pathway. Furthermore, these functions of Lys308 were largely dependent on its positively charged property. These data reveal previously unappreciated functions of helix 8 and novel mechanisms governing the cell surface transport and function of AT1aR.
Collapse
Affiliation(s)
- Shu Zhu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, 1459 Laney Walker Blvd., Augusta GA 30912, United States
| | - Maoxiang Zhang
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, 1459 Laney Walker Blvd., Augusta GA 30912, United States
| | - Jason E Davis
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, 1459 Laney Walker Blvd., Augusta GA 30912, United States
| | - William H Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, 1459 Laney Walker Blvd., Augusta GA 30912, United States
| | - Kristen Surrao
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, 1459 Laney Walker Blvd., Augusta GA 30912, United States
| | - Hong Wang
- School of Life Sciences and Technology, Tongji University, 1239 Siping Road, Shanghai, China
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, 1459 Laney Walker Blvd., Augusta GA 30912, United States.
| |
Collapse
|
10
|
Upadhyaya J, Singh N, Bhullar RP, Chelikani P. The structure–function role of C-terminus in human bitter taste receptor T2R4 signaling. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:1502-8. [DOI: 10.1016/j.bbamem.2015.03.035] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 03/10/2015] [Accepted: 03/31/2015] [Indexed: 11/15/2022]
|
11
|
Regulation of GPCR Anterograde Trafficking by Molecular Chaperones and Motifs. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 132:289-305. [PMID: 26055064 DOI: 10.1016/bs.pmbts.2015.02.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
G protein-coupled receptors (GPCRs) make up a superfamily of integral membrane proteins that respond to a wide variety of extracellular stimuli, giving them an important role in cell function and survival. They have also proven to be valuable targets in the fight against various diseases. As such, GPCR signal regulation has received considerable attention over the last few decades. With the amplitude of signaling being determined in large part by receptor density at the plasma membrane, several endogenous mechanisms for modulating GPCR expression at the cell surface have come to light. It has been shown that cell surface expression is determined by both exocytic and endocytic processes. However, the body of knowledge surrounding GPCR trafficking from the endoplasmic reticulum to the plasma membrane, commonly known as anterograde trafficking, has considerable room for growth. We focus here on the current paradigms of anterograde GPCR trafficking. We will discuss the regulatory role of both the general and "nonclassical private" chaperone systems in GPCR trafficking as well as conserved motifs that serve as modulators of GPCR export from the endoplasmic reticulum and Golgi apparatus. Together, these topics summarize some of the known mechanisms by which the cell regulates anterograde GPCR trafficking.
Collapse
|
12
|
Wu G, Davis JE, Zhang M. Regulation of α2B-Adrenerigc Receptor Export Trafficking by Specific Motifs. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 132:227-44. [PMID: 26055061 PMCID: PMC4827153 DOI: 10.1016/bs.pmbts.2015.03.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Intracellular trafficking and precise targeting to specific locations of G protein-coupled receptors (GPCRs) control the physiological functions of the receptors. Compared to the extensive efforts dedicated to understanding the events involved in the endocytic and recycling pathways, the molecular mechanisms underlying the transport of the GPCR superfamily from the endoplasmic reticulum (ER) through the Golgi to the plasma membrane are relatively less well defined. Over the past years, we have used α(2B)-adrenergic receptor (α(2B)-AR) as a model to define the factors that control GPCR export trafficking. In this chapter, we will review specific motifs identified to mediate the export of nascent α(2B)-AR from the ER and the Golgi and discuss the possible underlying mechanisms. As these motifs are highly conserved among GPCRs, they may provide common mechanisms for export trafficking of these receptors.
Collapse
Affiliation(s)
- Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, USA.
| | - Jason E Davis
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, USA
| | - Maoxiang Zhang
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, USA
| |
Collapse
|
13
|
Calcium-Sensing Receptor. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 132:127-50. [DOI: 10.1016/bs.pmbts.2015.02.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
14
|
Lachance V, Angers S, Parent JL. New insights in the regulation of Rab GTPases by G protein-coupled receptors. Small GTPases 2014; 5:e29039. [PMID: 24950538 DOI: 10.4161/sgtp.29039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Cargo-mediated regulation of vesicular transport has received great attention lately. Rab GTPases, forming the largest branch of the Ras GTPase superfamily, regulate almost every step of vesicle-mediated trafficking. Growing evidence suggests that mutations, aberrant expression, and altered post-translational modifications of Rab GTPases are associated with human diseases. However, their regulatory mechanisms and how they are connected to cargo proteins are still poorly understood. Accumulating data indicate that G protein-coupled receptors (GPCRs) directly associate with Rab GTPases and that these interactions dictate receptor trafficking. Yet, it remained unclear whether the receptors could regulate the targeting and activity of Rab GTPases in various cell compartments. It is only in recent years that experimental studies showed that GPCR signaling and interaction with Rab-associated regulatory proteins modulate the localization and activity of Rab GTPases. This research is revealing novel regulatory mechanisms of these small GTPases and should contribute to the progress in effective drug development. Recently published in the Journal of Cell Science, Lachance et al. present a novel role for ubiquitylation of Rab11a by a β2AR/HACE1 complex in regulating Rab11a activity and β2AR trafficking.
Collapse
Affiliation(s)
- Véronik Lachance
- Service de Rhumatologie; Département de Médecine; Faculté de Médecine et des Sciences de la Santé; and the Institut de Pharmacologie de Sherbrooke; Université de Sherbrooke; and the Centre de Recherche du Centre Hospitalier de l'Université de Sherbrooke, Sherbrooke, QC Canada
| | - Stéphane Angers
- Department of Pharmaceutical Sciences; Leslie Dan Faculty of Pharmacy; and the Department of Biochemistry; Faculty of Medicine; University of Toronto; Toronto, ON Canada
| | - Jean-Luc Parent
- Service de Rhumatologie; Département de Médecine; Faculté de Médecine et des Sciences de la Santé; and the Institut de Pharmacologie de Sherbrooke; Université de Sherbrooke; and the Centre de Recherche du Centre Hospitalier de l'Université de Sherbrooke, Sherbrooke, QC Canada
| |
Collapse
|
15
|
Bertuccio CA, Lee SL, Wu G, Butterworth MB, Hamilton KL, Devor DC. Anterograde trafficking of KCa3.1 in polarized epithelia is Rab1- and Rab8-dependent and recycling endosome-independent. PLoS One 2014; 9:e92013. [PMID: 24632741 PMCID: PMC3954861 DOI: 10.1371/journal.pone.0092013] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 02/16/2014] [Indexed: 02/01/2023] Open
Abstract
The intermediate conductance, Ca2+-activated K+ channel (KCa3.1) targets to the basolateral (BL) membrane in polarized epithelia where it plays a key role in transepithelial ion transport. However, there are no studies defining the anterograde and retrograde trafficking of KCa3.1 in polarized epithelia. Herein, we utilize Biotin Ligase Acceptor Peptide (BLAP)-tagged KCa3.1 to address these trafficking steps in polarized epithelia, using MDCK, Caco-2 and FRT cells. We demonstrate that KCa3.1 is exclusively targeted to the BL membrane in these cells when grown on filter supports. Following endocytosis, KCa3.1 degradation is prevented by inhibition of lysosomal/proteosomal pathways. Further, the ubiquitylation of KCa3.1 is increased following endocytosis from the BL membrane and PR-619, a deubiquitylase inhibitor, prevents degradation, indicating KCa3.1 is targeted for degradation by ubiquitylation. We demonstrate that KCa3.1 is targeted to the BL membrane in polarized LLC-PK1 cells which lack the μ1B subunit of the AP-1 complex, indicating BL targeting of KCa3.1 is independent of μ1B. As Rabs 1, 2, 6 and 8 play roles in ER/Golgi exit and trafficking of proteins to the BL membrane, we evaluated the role of these Rabs in the trafficking of KCa3.1. In the presence of dominant negative Rab1 or Rab8, KCa3.1 cell surface expression was significantly reduced, whereas Rabs 2 and 6 had no effect. We also co-immunoprecipitated KCa3.1 with both Rab1 and Rab8. These results suggest these Rabs are necessary for the anterograde trafficking of KCa3.1. Finally, we determined whether KCa3.1 traffics directly to the BL membrane or through recycling endosomes in MDCK cells. For these studies, we used either recycling endosome ablation or dominant negative RME-1 constructs and determined that KCa3.1 is trafficked directly to the BL membrane rather than via recycling endosomes. These results are the first to describe the anterograde and retrograde trafficking of KCa3.1 in polarized epithelia cells.
Collapse
Affiliation(s)
- Claudia A. Bertuccio
- Department of Cell Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Shih-Liang Lee
- Department of Physiology, Otago School of Medical Sciences, University of Otago, Dunedin, Otago, New Zealand
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, United States of America
| | - Michael B. Butterworth
- Department of Cell Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Kirk L. Hamilton
- Department of Physiology, Otago School of Medical Sciences, University of Otago, Dunedin, Otago, New Zealand
- * E-mail: (DCD); (KLH)
| | - Daniel C. Devor
- Department of Cell Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- * E-mail: (DCD); (KLH)
| |
Collapse
|
16
|
Pinto S, Martínez-Romero A, O'Connor JE, Gil-Benso R, San-Miguel T, Terrádez L, Monteagudo C, Callaghan RC. Intracellular coexpression of CXC- and CC- chemokine receptors and their ligands in human melanoma cell lines and dynamic variations after xenotransplantation. BMC Cancer 2014; 14:118. [PMID: 24559071 PMCID: PMC3943502 DOI: 10.1186/1471-2407-14-118] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 02/14/2014] [Indexed: 12/05/2022] Open
Abstract
Background Chemokines have been implicated in tumor progression and metastasis. In melanoma, chemokine receptors have been implicated in organ selective metastasis by regulating processes such as chemoattraction, adhesion and survival. Methods In this study we have analyzed, using flow cytometry, the systems formed by the chemokine receptors CXCR3, CXCR4, CXCR7, CCR7 and CCR10 and their ligands in thirteen human melanoma cell lines (five established from primary tumors and eight established from metastasis from different tissues). WM-115 and WM-266.4 melanoma cell lines (obtained from a primary and a metastatic melanoma respectively) were xenografted in nude mice and the tumors and cell lines derived from them were also analyzed. Results Our results show that the melanoma cell lines do not express or express in a low degree the chemokine receptors on their cell surface. However, melanoma cell lines show intracellular expression of all the aforementioned receptors and most of their respective ligands. When analyzing the xenografts and the cell lines obtained from them we found variations in the intracellular expression of chemokines and chemokine receptors that differed between the primary and metastatic cell lines. However, as well as in the original cell lines, minute or no expression of the chemokine receptors was observed at the cell surface. Conclusions Coexpression of chemokine receptors and their ligands was found in human melanoma cell lines. However, this expression is intracellular and receptors are not found at the cell membrane nor chemokines are secreted to the cell medium. The levels of expressed chemokine receptors and their ligands show dynamic variations after xenotransplantation that differ depending on the origin of the cell line (from primary tumor or from metastasis).
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Robert C Callaghan
- Cytomics Laboratory, Mixed Unit CIPF-UVEG, Príncipe Felipe Research Centre, Valencia, Avda Autopista del Saler, 16, 46012 Valencia, Spain.
| |
Collapse
|
17
|
Babilon S, Mörl K, Beck-Sickinger AG. Towards improved receptor targeting: anterograde transport, internalization and postendocytic trafficking of neuropeptide Y receptors. Biol Chem 2013; 394:921-36. [DOI: 10.1515/hsz-2013-0123] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2013] [Accepted: 02/22/2013] [Indexed: 01/10/2023]
Abstract
Abstract
The neuropeptide Y system is known to be involved in the regulation of many central physiological and pathophysiological processes, such as energy homeostasis, obesity, cancer, mood disorders and epilepsy. Four Y receptor subtypes have been cloned from human tissue (hY1, hY2, hY4 and hY5) that form a multiligand/multireceptor system together with their three peptidic agonists (NPY, PYY and PP). Addressing this system for medical application requires on the one hand detailed information about the receptor-ligand interaction to design subtype-selective compounds. On the other hand comprehensive knowledge about alternative receptor signaling, as well as desensitization, localization and downregulation is crucial to circumvent the development of undesired side-effects and drug resistance. By bringing such knowledge together, highly potent and long-lasting drugs with minimized side-effects can be engineered. Here, current knowledge about Y receptor export, internalization, recycling, and degradation is summarized, with a focus on the human Y receptor subtypes, and is discussed in terms of its impact on therapeutic application.
Collapse
|
18
|
Zhang X, Wang H, Duvernay MT, Zhu S, Wu G. The angiotensin II type 1 receptor C-terminal Lys residues interact with tubulin and modulate receptor export trafficking. PLoS One 2013; 8:e57805. [PMID: 23451270 PMCID: PMC3581488 DOI: 10.1371/journal.pone.0057805] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 01/25/2013] [Indexed: 12/15/2022] Open
Abstract
The physiological and pathological functions of angiotensin II are largely mediated through activating the cell surface angiotensin II type 1 receptor (AT1R). However, the molecular mechanisms underlying the transport of newly synthesized AT1R from the endoplasmic reticulum (ER) to the cell surface remain poorly defined. Here we demonstrated that the C-terminus (CT) of AT1R directly and strongly bound to tubulin and the binding domains were mapped to two consecutive Lys residues at positions 310 and 311 in the CT membrane-proximal region of AT1R and the acidic CT of tubulin, suggestive of essentially ionic interactions between AT1R and tubulin. Furthermore, mutation to disrupt tubulin binding dramatically inhibited the cell surface expression of AT1R, arrested AT1R in the ER, and attenuated AT1R-mediated signaling measured as ERK1/2 activation. These data demonstrate for the first time that specific Lys residues in the CT juxtamembrane region regulate the processing of AT1R through interacting with tubulin. These data also suggest an important role of the microtubule network in the cell surface transport of AT1R.
Collapse
Affiliation(s)
- Xiaoping Zhang
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Hong Wang
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
- School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Matthew T. Duvernay
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Shu Zhu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, United States of America
| | - Guangyu Wu
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, United States of America
- * E-mail:
| |
Collapse
|
19
|
Gronemeyer T, Wiese S, Grinhagens S, Schollenberger L, Satyagraha A, Huber LA, Meyer HE, Warscheid B, Just WW. Localization of Rab proteins to peroxisomes: a proteomics and immunofluorescence study. FEBS Lett 2013; 587:328-38. [PMID: 23333653 DOI: 10.1016/j.febslet.2012.12.025] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 12/19/2012] [Accepted: 12/19/2012] [Indexed: 11/18/2022]
Abstract
A proteomics screen was initiated to identify Rab proteins regulating transport to and away from peroxisomes. Mass spectrometry-based protein correlation profiling of rat liver organelles and immunofluorescence analysis of the peroxisome candidate Rab proteins revealed Rab6, Rab10, Rab14 and Rab18 to associate with the peroxisomal membrane. While Rab14 localized to peroxisomes predominantly in its dominant-active form, other Rab proteins associated with peroxisomes in both their GTP- and GDP-bound state. In summary, our data suggest that Rab6, Rab10, Rab14 and Rab18 associate with the peroxisomal compartment and similar as previously shown for Rab8, Rab18 in its GDP-bound state favors peroxisome proliferation.
Collapse
Affiliation(s)
- Thomas Gronemeyer
- Department of Molecular Genetics and Cell Biology, Ulm University, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
20
|
A new vesicular scaffolding complex mediates the G-protein-coupled 5-HT1A receptor targeting to neuronal dendrites. J Neurosci 2013; 32:14227-41. [PMID: 23055492 DOI: 10.1523/jneurosci.6329-11.2012] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Although essential for their neuronal function, the molecular mechanisms underlying the dendritic targeting of serotonin G-protein-coupled receptors are poorly understood. Here, we characterized a Yif1B-dependent vesicular scaffolding complex mediating the intracellular traffic of the rat 5-HT(1A) receptor (5-HT(1A)R) toward dendrites. By combining directed mutagenesis, GST-pull down, and surface plasmon resonance, we identified a tribasic motif in the C-tail of the 5-HT(1A)R on which Yif1B binds directly with high affinity (K(D) ≈ 37 nM). Moreover, we identified Yip1A, Rab6, and Kif5B as new partners of the 5-HT(1A)R/Yif1B complex, and showed that their expression in neurons is also crucial for the dendritic targeting of the 5-HT(1A)R. Live videomicroscopy revealed that 5-HT(1A)R, Yif1B, Yip1A, and Rab6 traffic in vesicles exiting the soma toward the dendritic tree, and also exhibit bidirectional motions, sustaining their role in 5-HT(1A)R dendritic targeting. Hence, we propose a new trafficking pathway model in which Yif1B is the scaffold protein recruiting the 5-HT(1A)R in a complex including Yip1A and Rab6, with Kif5B and dynein as two opposite molecular motors coordinating the traffic of vesicles along dendritic microtubules. This targeting pathway opens new insights for G-protein-coupled receptors trafficking in neurons.
Collapse
|
21
|
Abstract
In addition to heterotrimeric G-proteins, Ras-like small GTPases are also involved in regulating physiological functions of the G-protein-coupled receptor (GPCR) superfamily. In particular, Rab and ARF GTPases function either as "traffic cops" to coordinate receptor targeting to specific locations or as "signal transducers" to directly mediate receptor signal propagation. As revealed in protein-protein interaction assays, GPCRs may use specific motifs to physically interact with small GTPases, providing important insights into the underlying molecular mechanisms. In this chapter, we describe coimmunoprecipitation and GST fusion protein pull-down approaches to study the GPCR-small GTPase interaction, by focusing on the interaction of α(2B)- and β(2)-adrenegic receptors with the small GTPases Rab8 and ARF1.
Collapse
Affiliation(s)
- Chunmin Dong
- Department of Pharmacology and Toxicology, Georgia Health Sciences University, Augusta, Georgia, USA
| | | |
Collapse
|
22
|
Lachance V, Degrandmaison J, Marois S, Robitaille M, Génier S, Nadeau S, Angers S, Parent JL. Ubiquitination and activation of a Rab GTPase promoted by a β2-Adrenergic Receptor/HACE1 complex. J Cell Sci 2013; 127:111-23. [DOI: 10.1242/jcs.132944] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
We and others have shown that trafficking of G protein-coupled receptors is regulated by Rab GTPases. Cargo-mediated regulation of vesicular transport has received great attention lately. Rab GTPases, forming the largest branch of the Ras GTPase superfamily, regulate almost every step of vesicle-mediated trafficking. Rab GTPases are well-recognized targets of human diseases but their regulation and the mechanisms connecting them to cargo proteins are still poorly understood. Herein, we show by overexpression/depletion studies that HACE1, a HECT domain-containing ubiquitin ligase, promotes the recycling of the β2-adrenergic receptor (β2AR), a prototypical G protein-coupled receptor, through a Rab11a-dependent mechanism. Interestingly, the β2AR in conjunction with HACE1 triggered ubiquitination of Rab11a, as observed by Western blot analysis. LC-MS/MS experiments determined that Rab11a is ubiquitnatied on Lys145. A Rab11a-K145R mutant failed to undergo β2AR/HACE1-induced ubiquitination and inhibited the HACE1-mediated recycling of the β2AR. Rab11a, but not Rab11a-K145R, was activated by β2AR/HACE1 indicating that ubiquitination of Lys145 is involved in Rab11a activation. β2AR/HACE1 co-expression also potentiated ubiquitination of Rab6a and Rab8a, but not of other Rab GTPases that were tested. We report a novel regulatory mechanism of Rab GTPases by their ubiquitination with associated functional effects demonstrated on Rab11a. This partakes into a new pathway whereby a cargo protein, like a G protein-coupled receptor, can regulate its own trafficking by inducing the ubiquitination and activation of a Rab GTPase.
Collapse
|
23
|
Fan Y, Li C, Guo J, Hu G, Wu G. A single lys residue on the first intracellular loop modulates the endoplasmic reticulum export and cell-surface expression of α2A-adrenergic receptor. PLoS One 2012; 7:e50416. [PMID: 23227171 PMCID: PMC3515576 DOI: 10.1371/journal.pone.0050416] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 10/19/2012] [Indexed: 12/03/2022] Open
Abstract
Export from the endoplasmic reticulum (ER) represents an initial step in intracellular trafficking of G protein-coupled receptors (GPCRs). However, the underlying molecular mechanisms remain poorly understood. We have previously demonstrated that a highly conserved Leu residue on the first intracellular loop (ICL1) is required for exit of several GPCRs from the ER. Here we found that, in addition to Leu64 residue in the ICL1, the neighboring positively charged residue Lys65also modulates the cell-surface transport of α2A-adrenergic receptor (α2A-AR). Mutation of Lys65 to Ala, Glu and Gln significantly attenuated, whereas mutation of Lys65 to Arg strongly augmented α2A-AR expression at the cell surface. Consistent with the effects on the cell-surface expression of α2A-AR, mutation of Lys65 to Ala and Arg produced opposing effects on α2A-AR-mediated ERK1/2 activation. Furthermore, confocal microscopy revealed that the α2A-AR mutant K65A displayed a strong intracellular expression pattern and was extensively co-localized with the ER marker DsRed2-ER, suggestive of ER accumulation. These data provide the first evidence indicating an important function for a single Lys residue on the ICL1 in the ER export and cell-surface expression of α2A-AR. These data also suggest that the ICL1 may possess multiple signals that control the cell-surface targeting of GPCRs via distinct mechanisms.
Collapse
Affiliation(s)
- Yi Fan
- Department of Pharmacology and Toxicology, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Chunman Li
- Department of Pharmacology and Toxicology, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Jianhui Guo
- Department of Pharmacology and Toxicology, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Gang Hu
- Department of Pharmacology, Nanjing Medical University, Nanjing, China
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Georgia Health Sciences University, Augusta, Georgia, United States of America
- * E-mail:
| |
Collapse
|
24
|
Li C, Fan Y, Lan TH, Lambert NA, Wu G. Rab26 modulates the cell surface transport of α2-adrenergic receptors from the Golgi. J Biol Chem 2012; 287:42784-94. [PMID: 23105096 DOI: 10.1074/jbc.m112.410936] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The molecular mechanisms underlying the transport from the Golgi to the cell surface of G protein-coupled receptors remain poorly elucidated. Here we determined the role of Rab26, a Ras-like small GTPase involved in vesicle-mediated secretion, in the cell surface export of α(2)-adrenergic receptors. We found that transient expression of Rab26 mutants and siRNA-mediated depletion of Rab26 significantly attenuated the cell surface numbers of α(2A)-AR and α(2B)-AR, as well as ERK1/2 activation by α(2B)-AR. Furthermore, the receptors were extensively arrested in the Golgi by Rab26 mutants and siRNA. Moreover, Rab26 directly and activation-dependently interacted with α(2B)-AR, specifically the third intracellular loop. These data demonstrate that the small GTPase Rab26 regulates the Golgi to cell surface traffic of α(2)-adrenergic receptors, likely through a physical interaction. These data also provide the first evidence implicating an important function of Rab26 in coordinating plasma membrane protein transport.
Collapse
Affiliation(s)
- Chunman Li
- Department of Pharmacology and Toxicology, Georgia Health Sciences University, Augusta, Georgia 30912, USA
| | | | | | | | | |
Collapse
|
25
|
Cottam NP, Ungar D. Retrograde vesicle transport in the Golgi. PROTOPLASMA 2012; 249:943-55. [PMID: 22160157 DOI: 10.1007/s00709-011-0361-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Accepted: 11/29/2011] [Indexed: 05/23/2023]
Abstract
The Golgi apparatus is the central sorting and biosynthesis hub of the secretory pathway, and uses vesicle transport for the recycling of its resident enzymes. This system must operate with high fidelity and efficiency for the correct modification of secretory glycoconjugates. In this review, we discuss recent advances on how coats, tethers, Rabs and SNAREs cooperate at the Golgi to achieve vesicle transport. We cover the well understood vesicle formation process orchestrated by the COPI coat, and the comprehensively documented fusion process governed by a set of Golgi localised SNAREs. Much less clear are the steps in-between formation and fusion of vesicles, and we therefore provide a much needed update of the latest findings about vesicle tethering. The interplay between Rab GTPases, golgin family coiled-coil tethers and the conserved oligomeric Golgi (COG) complex at the Golgi are thoroughly evaluated.
Collapse
Affiliation(s)
- Nathanael P Cottam
- Department of Biology (Area 9), University of York, Heslington, York, YO10 5DD, UK
| | | |
Collapse
|
26
|
Deeba F, Pandey AK, Ranjan S, Mishra A, Singh R, Sharma YK, Shirke PA, Pandey V. Physiological and proteomic responses of cotton (Gossypium herbaceum L.) to drought stress. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2012; 53:6-18. [PMID: 22285410 DOI: 10.1016/j.plaphy.2012.01.002] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Accepted: 01/03/2012] [Indexed: 05/18/2023]
Abstract
Cotton genotype RAHS 187 was analyzed for changes in physiology, biochemistry and proteome due to drought stress. The deleterious effect of drought in cotton plants was mainly targeted towards photosynthesis. The gas-exchange parameters of net photosynthesis (A), stomatal conductance (g(s)) and transpiration (E) showed a decreasing trend as the drought intensity increased. The fluorescence parameters of, effective quantum yield of PSII (Φ(PSII)), and electron transport rates (ETR), also showed a declining trend. As the intensity of drought increased, both H(2)O(2) and MDA levels increased indicating oxidative stress. Anthocyanin levels were increased by more than four folds in the droughted plants. Two-dimensional gel electrophoresis detected more than 550 protein spots. Significantly expressed proteins were analyzed by peptide mass fingerprinting (PMF) using MALDI-TOF-TOF. The number of up-regulated spots was found to be 16 while 6 spots were down-regulated. The reasonable implications in drought response of the identified proteins vis-à-vis physiological changes are discussed. Results provide some additional information that can lead to a better understanding of the molecular basis of drought-sensitivity in cotton plants.
Collapse
Affiliation(s)
- Farah Deeba
- Plant Physiology Lab, Council of Scientific and Industrial Research - National Botanical Research Institute, Rana Pratap Marg, Lucknow 226 001, U.P., India
| | | | | | | | | | | | | | | |
Collapse
|
27
|
Sugawara T, Nakatsu D, Kii H, Maiya N, Adachi A, Yamamoto A, Kano F, Murata M. PKCδ and ε regulate the morphological integrity of the ER–Golgi intermediate compartment (ERGIC) but not the anterograde and retrograde transports via the Golgi apparatus. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1823:861-75. [DOI: 10.1016/j.bbamcr.2012.01.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 01/13/2012] [Accepted: 01/17/2012] [Indexed: 02/03/2023]
|
28
|
Anterograde trafficking of nascent α(2B)-adrenergic receptor: structural basis, roles of small GTPases. CURRENT TOPICS IN MEMBRANES 2012; 67:79-100. [PMID: 21771486 DOI: 10.1016/b978-0-12-384921-2.00004-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
|
29
|
Abstract
Anterograde trafficking of newly synthesized G protein-coupled -receptors (GPCRs) from the endoplasmic reticulum to the cell surface represents a crucial checkpoint in controlling the amount of the functional receptors at the cell surface and the strength of signaling initiated by the receptors. In contrast to the extensively studied, well-understood endocytic and recycling pathways, the molecular mechanisms underlying the cell-surface targeting of the receptors remain poorly defined. In this chapter, I will discuss current advances in understanding post-Golgi transport of GPCRs by focusing on specific motifs or sequences that may function as sorting signals regulating export from the Golgi and subsequent transport to the plasma membrane of GPCRs.
Collapse
|
30
|
Dong C, Li C, Wu G. Regulation of α(2B)-adrenergic receptor-mediated extracellular signal-regulated kinase 1/2 (ERK1/2) activation by ADP-ribosylation factor 1. J Biol Chem 2011; 286:43361-9. [PMID: 22025613 DOI: 10.1074/jbc.m111.267286] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
A number of signaling molecules are involved in the activation of the mitogen-activated protein kinase (MAPK) pathway by G protein-coupled receptors. In this study, we have demonstrated that α(2B)-adrenergic receptor (α(2B)-AR) interacts with ADP-ribosylation factor 1 (ARF1), a small GTPase involved in vesicle-mediated trafficking, in an agonist activation-dependent manner and that the interaction is mediated through a unique double Trp motif in the third intracellular loop of the receptor. Interestingly, mutation of the double Trp motif and siRNA-mediated depletion of ARF1 attenuate α(2B)-AR-mediated activation of extracellular signal-regulated kinases 1/2 (ERK1/2) without altering receptor intracellular trafficking, whereas expression of the constitutively active mutant ARF1Q71L and ARNO, a GDP-GTP exchange factor of ARF1, markedly enhances the activation of Raf1, MEK1, and ERK1/2. These data strongly demonstrate that the small GTPase ARF1 modulates ERK1/2 activation by α(2B)-AR and provide the first evidence indicating a novel function for ARF1 in regulating the MAPK signaling pathway.
Collapse
Affiliation(s)
- Chunmin Dong
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, USA
| | | | | |
Collapse
|
31
|
Wang G, Wu G. Small GTPase regulation of GPCR anterograde trafficking. Trends Pharmacol Sci 2011; 33:28-34. [PMID: 22015208 DOI: 10.1016/j.tips.2011.09.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Revised: 09/15/2011] [Accepted: 09/19/2011] [Indexed: 01/14/2023]
Abstract
The physiological functions of heterotrimeric G protein-coupled receptors (GPCRs) are dictated by their intracellular trafficking and precise targeting to the functional destinations. Over the past decades, most studies on the trafficking of GPCRs have focused on the events involved in endocytosis and recycling. By contrast, the molecular mechanisms underlying anterograde transport of newly synthesized GPCRs from the endoplasmic reticulum (ER) to the cell surface have only now begun to be revealed. In this review we discuss current advances in understanding the role of Ras-like GTPases, specifically the Rab and Sar1/ARF subfamilies, in regulating cell-surface transport of GPCRs en route from the ER and the Golgi.
Collapse
Affiliation(s)
- Guansong Wang
- Institute of Respiratory Diseases, Second Affiliated Hospital of the Third Military Medical University, Chongqing 400037, China
| | | |
Collapse
|
32
|
Zhang X, Dong C, Wu QJ, Balch WE, Wu G. Di-acidic motifs in the membrane-distal C termini modulate the transport of angiotensin II receptors from the endoplasmic reticulum to the cell surface. J Biol Chem 2011; 286:20525-35. [PMID: 21507945 DOI: 10.1074/jbc.m111.222034] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The molecular mechanisms underlying the endoplasmic reticulum (ER) export and cell surface transport of nascent G protein-coupled receptors (GPCRs) have just begun to be revealed and previous studies have shown that hydrophobic motifs in the putative amphipathic 8(th) α-helical region within the membrane-proximal C termini play an important role. In this study, we demonstrate that di-acidic motifs in the membrane-distal, nonstructural C-terminal portions are required for the exit from the ER and transport to the plasma membrane of angiotensin II receptors, but not adrenergic receptors. More interestingly, distinct di-acidic motifs dictate optimal export trafficking of different angiotensin II receptors and export ability of each acidic residue in the di-acidic motifs cannot be fully substituted by other acidic residue. Moreover, the function of the di-acidic motifs is likely mediated through facilitating the recruitment of the receptors onto the ER-derived COPII transport vesicles. Therefore, the di-acidic motifs located in the membrane-distal C termini may represent the first linear motifs which recruit selective GPCRs onto the COPII vesicles to control their export from the ER.
Collapse
Affiliation(s)
- Xiaoping Zhang
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, USA
| | | | | | | | | |
Collapse
|
33
|
Duvernay MT, Wang H, Dong C, Guidry JJ, Sackett DL, Wu G. Alpha2B-adrenergic receptor interaction with tubulin controls its transport from the endoplasmic reticulum to the cell surface. J Biol Chem 2011; 286:14080-9. [PMID: 21357695 DOI: 10.1074/jbc.m111.222323] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
It is well recognized that the C terminus (CT) plays a crucial role in modulating G protein-coupled receptor (GPCR) transport from the endoplasmic reticulum (ER) to the cell surface. However the molecular mechanisms that govern CT-dependent ER export remain elusive. To address this issue, we used α(2B)-adrenergic receptor (α(2B)-AR) as a model GPCR to search for proteins interacting with the CT. By using peptide-conjugated affinity matrix combined with proteomics and glutathione S-transferase fusion protein pull-down assays, we identified tubulin directly interacting with the α(2B)-AR CT. The interaction domains were mapped to the acidic CT of tubulin and the basic Arg residues in the α(2B)-AR CT, particularly Arg-437, Arg-441, and Arg-446. More importantly, mutation of these Arg residues to disrupt tubulin interaction markedly inhibited α(2B)-AR transport to the cell surface and strongly arrested the receptor in the ER. These data provide the first evidence indicating that the α(2B)-AR C-terminal Arg cluster mediates its association with tubulin to coordinate its ER-to-cell surface traffic and suggest a novel mechanism of GPCR export through physical contact with microtubules.
Collapse
Affiliation(s)
- Matthew T Duvernay
- From the Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112
| | | | | | | | | | | |
Collapse
|
34
|
Huang TH, Ka SM, Hsu YJ, Shui HA, Tang BL, Hu KY, Chang JL, Chen A. Rab23 plays a role in the pathophysiology of mesangial cells--a proteomic analysis. Proteomics 2011; 11:380-94. [PMID: 21268268 DOI: 10.1002/pmic.201000165] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Revised: 10/13/2010] [Accepted: 11/02/2010] [Indexed: 12/23/2022]
Abstract
Rab23, a novel member of the Rab family of small GTPases, has recently been identified in mesangial cells (MCs). Although Rab23 levels in MCs are associated with glomerular nephropathies, the exact physiological and pathological roles of Rab23 in MCs are unknown. In the present study, its roles in MCs were explored by performing proteomics and systems biology analyses in MCs after knockdown or overexpression of Rab23. Knockdown of Rab23 was achieved by transfecting MCs with a plasmid expressing short hairpin RNA against Rab23, while overexpression of Rab23 was accomplished by transfection with the wild-type, dominant negative, and constitutively active Rab23 gene constructs. The effects of different levels of Rab23 activity on proteome of various biological pathways were investigated. Gel-based proteomic approaches and systems biology tools, respectively, were used to identify the Rab23-regulated proteins and the functional pathways. Proteomic analysis revealed the potential roles for Rab23 in multiple processes, including G-protein signal transduction, transcription modulation, RNA stabilization, protein synthesis and degradation, cytoskeleton reorganization, anti-oxidation and detoxification, circadian rhythm regulation and phagocytosis. Bioinformatics analyses showed that Rab23 impacts on multiple biological networks in MCs. These data may shed light on the roles of Rab23 in mesangiopathy or MC damage.
Collapse
Affiliation(s)
- Tzu-Hao Huang
- Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan
| | | | | | | | | | | | | | | |
Collapse
|
35
|
Zhuang X, Adipietro KA, Datta S, Northup JK, Ray K. Rab1 small GTP-binding protein regulates cell surface trafficking of the human calcium-sensing receptor. Endocrinology 2010; 151:5114-23. [PMID: 20861236 PMCID: PMC2954715 DOI: 10.1210/en.2010-0422] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The human calcium-sensing receptor (hCaR) is a family-3/C G-protein-coupled receptor that regulates Ca(2+) homeostasis by controlling parathyroid hormone secretion. Here we investigated the role of Rab1, a small GTP-binding protein that specifically regulates protein transport from the endoplasmic reticulum to the Golgi, in cell surface transport of the hCaR. Cell surface expression of hCaR transiently expressed in human embryonic kidney 293 cells was strongly augmented by coexpression of Rab1 and attenuated by disruption of endogenous Rab1 function by expression of the dominant-negative Rab1N124I mutant or depletion of Rab1 with small interfering RNA. Rab1N124I expression also partially attenuated cell surface expression and signaling response to gain-of-function mutants of hCaR with truncated carboxyl-terminal sequences at positions 895 and 903. These carboxyl-tail truncations are similar to a deletion between residues S895 and V1075 found in a patient family causing autosomal dominant hypocalcemia. In addition, coexpression with wild-type Rab1 increased cell surface expression of the loss-of-function missense mutation R185Q, located on the hCaR amino-terminal extracellular ligand-binding domain (ECD), which causes familial hypocalciuric hypercalcemia. Truncated hCaR variants containing either the ECD with the first transmembrane helix or only the ECD also display Rab1-dependent cell surface expression or secretion into the culture medium, respectively. These data reveal a role for Rab1 in hCaR trafficking from the endoplasmic reticulum to the Golgi that regulates receptor cell surface expression and thereby cell signaling responsiveness to extracellular calcium.
Collapse
Affiliation(s)
- Xiaolei Zhuang
- Laboratory of Cellular Biology, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland 20892, USA
| | | | | | | | | |
Collapse
|
36
|
Dong C, Yang L, Zhang X, Gu H, Lam ML, Claycomb WC, Xia H, Wu G. Rab8 interacts with distinct motifs in alpha2B- and beta2-adrenergic receptors and differentially modulates their transport. J Biol Chem 2010; 285:20369-80. [PMID: 20424170 DOI: 10.1074/jbc.m109.081521] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The molecular mechanism underlying the post-Golgi transport of G protein-coupled receptors (GPCRs) remains poorly understood. Here we determine the role of Rab8 GTPase, which modulates vesicular protein transport between the trans-Golgi network (TGN) and the plasma membrane, in the cell surface targeting of alpha(2B)- and beta(2)-adrenergic receptors (AR). Transient expression of GDP- and GTP-bound Rab8 mutants and short hairpin RNA-mediated knockdown of Rab8 more potently inhibited the cell surface expression of alpha(2B)-AR than beta(2)-AR. The GDP-bound Rab8(T22N) mutant attenuated ERK1/2 activation by alpha(2B)-AR, but not beta(2)-AR, and arrested alpha(2B)-AR in the TGN compartment. Co-immunoprecipitation revealed that both alpha(2B)-AR and beta(2)-AR physically interacted with Rab8 and glutathione S-transferase fusion protein pulldown assays demonstrated that Rab8 interacted with the C termini of both receptors. Interestingly, mutation of the highly conserved membrane-proximal C terminus dileucine motif selectively blocked beta(2)-AR interaction with Rab8, whereas mutation of residues Val(431)-Phe(432)-Asn(433)-Gln(434), Pro(447)-Trp(448), Gln(450)-Thr(451), and Trp(453) in the C terminus impaired alpha(2B)-AR interaction with Rab8. Furthermore, transport inhibition by Rab8(T22N) of a chimeric beta(2)-AR carrying the alpha(2B)-AR C terminus was similar to alpha(2B)-AR. These data provide strong evidence indicating that Rab8 GTPase interacts with distinct motifs in the C termini of alpha(2B)-AR and beta(2)-AR and differentially modulates their traffic from the TGN to the cell surface.
Collapse
Affiliation(s)
- Chunmin Dong
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, USA
| | | | | | | | | | | | | | | |
Collapse
|
37
|
Dong C, Zhang X, Zhou F, Dou H, Duvernay MT, Zhang P, Wu G. ADP-ribosylation factors modulate the cell surface transport of G protein-coupled receptors. J Pharmacol Exp Ther 2010; 333:174-83. [PMID: 20093398 DOI: 10.1124/jpet.109.161489] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
ADP-ribosylation factors (ARFs) regulate vesicular traffic through recruiting coat proteins. However, their functions in the anterograde transport of nascent G protein-coupled receptors (GPCRs) from the endoplasmic reticulum to the plasma membrane remain poorly explored. Here we show that treatment with brefeldin A, an inhibitor of guanine nucleotide exchange on ARFs, markedly attenuated the cell surface numbers of alpha(2B)-adrenergic receptor (AR), beta(2)-AR, angiotensin II type 1 receptor, and chemokine (CXC motif) receptor 4. Functional inhibition of individual ARF GTPases by transient expression of the GDP-bound, GTP-bound, and guanine nucleotide-deficient mutants showed that the five human ARFs differentially modulated receptor cell surface expression and that the ARF1 mutants produced the most profound inhibitory effect. Furthermore, expression of the ARF1 GTPase-activating protein (GAP) ARFGAP1 significantly blocked receptor transport. Interestingly, the GDP- and GTP-bound ARF1 mutants arrested the receptors in distinct intracellular compartments. Consistent with the reduced receptor cell surface expression, extracellular signal-regulated kinase 1 and 2 activation by receptor agonists was significantly attenuated by the GDP-bound mutant ARF1T31N. Moreover, coimmunoprecipitation showed that alpha(2B)-AR associated with ARF1 and glutathione transferase pull-down assay indicated that the alpha(2B)-AR C terminus directly interacted with ARF1. These data show that ARF1 GTPase is involved in the regulation of cell surface expression of GPCRs at multiple transport steps.
Collapse
Affiliation(s)
- Chunmin Dong
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, LA 70112, USA
| | | | | | | | | | | | | |
Collapse
|
38
|
Williams D, Devi LA. Escorts take the lead molecular chaperones as therapeutic targets. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2010; 91:121-49. [PMID: 20691961 DOI: 10.1016/s1877-1173(10)91005-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The functional and physiological diversity of transmembrane receptors results from factors that influence the pharmacology, signaling, and trafficking of these receptors. Receptor mutations and other modifications may lead to misfolding, intracellular retention, and ineffective signaling of transmembrane receptors. The importance of such mutations is highlighted by the fact that various diseases have been linked to mutations that lead to ineffective signaling of these receptors, resulting from the retention of receptors in intracellular compartments. Studies focused on understanding the regulation of trafficking and cell surface expression of newly synthesized receptors have highlighted molecular chaperones as key regulators of receptor maturation and sorting. In this chapter, we discuss the functions of molecular chaperones in the regulation of seven-transmembrane-containing G-protein-coupled receptor function and trafficking and explore ways in which chaperones can serve as novel therapeutic targets.
Collapse
Affiliation(s)
- Dumaine Williams
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, USA
| | | |
Collapse
|
39
|
Heidecker B, Lamirault G, Kasper EK, Wittstein IS, Champion HC, Breton E, Russell SD, Hall J, Kittleson MM, Baughman KL, Hare JM. The gene expression profile of patients with new-onset heart failure reveals important gender-specific differences. Eur Heart J 2009; 31:1188-96. [PMID: 20031959 DOI: 10.1093/eurheartj/ehp549] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
AIMS We sought to test the hypothesis that inherent biological factors contribute to gender differences in disease pathophysiology of new-onset heart failure (HF), which can be detected from the transcriptome of a single endomyocardial biopsy (EMB). METHODS AND RESULTS We analysed samples from male (n = 29) and female patients (n = 14) with idiopathic dilated cardiomyopathy (IDCM) and new-onset HF with U133 Plus 2.0 microarrays (Affymetrix) and significance analysis of microarrays (SAM). There were 35 overexpressed and 16 downregulated transcripts in men vs. women [q < 5%, fold change (FC) > 1.2]. In addition to overexpression of Y-chromosome-related transcripts (n = 18), such as USP9Y (FC > 13.1), DDX3Y (FC > 11.3), RPS4Y1 (FC > 9.9), and EIF1AY (FC > 11.8) in males, there was overexpression of CD24 (FC > 5.6) and KCNK1 (FC > 1.5). In females, XIST was highly overexpressed (FC > 28.9), together with X-linked zinc finger proteins (FC > 1.9) and autosomal genes GATAD1 (FC > 1.6), SLC2A12 (FC > 2.9), and PDE6B (FC > 1.5). Analysis of a public data set of end-stage IDCM (n = 15) resulted in approximately 85% overlap with our findings. CONCLUSION This is the first study that identified gender-specific transcriptomic differences in new-onset HF. Our findings may offer novel insights into fundamental biological differences in the pathophysiology of HF between sexes and provide a platform for personalized medicine.
Collapse
Affiliation(s)
- Bettina Heidecker
- Interdisciplinary Stem Cell Institute, University of Miami, Miller School of Medicine, Biomedical Research, Miami, FL 33101, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Cell type-specific and light-dependent expression of Rab1 and Rab6 GTPases in mammalian retinas. Vis Neurosci 2009; 26:443-52. [PMID: 20003598 DOI: 10.1017/s0952523809990277] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The Ras-like Rab1 and Rab6 GTPases modulate protein traffic along the early secretory pathway and are involved in the regulation of maturation of rhodopsin in the outer retina. However, Rab GTPases have not been studied in the inner retinas. Here, we analyzed the anatomatic distribution and expression of Rab1 and Rab6 in the mouse and rat retinas by immunohistochemistry and immunoblotting. We found that Rab1 was specifically expressed in the rod bipolar cells, while Rab6 was expressed in a different cell type(s) from rod bipolar cells in the inner retina. We also demonstrated that expression of Rab1 and Rab6 was increased with light. These data provided the first evidence implicating that Rab1 and Rab6 may be involved in the regulation of the retinal adaptation.
Collapse
|
41
|
Sumakovic M, Hegermann J, Luo L, Husson SJ, Schwarze K, Olendrowitz C, Schoofs L, Richmond J, Eimer S. UNC-108/RAB-2 and its effector RIC-19 are involved in dense core vesicle maturation in Caenorhabditis elegans. ACTA ACUST UNITED AC 2009; 186:897-914. [PMID: 19797081 PMCID: PMC2753160 DOI: 10.1083/jcb.200902096] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Uncoordinated movement in Rab2 mutants is caused by impaired retention of cargo on dense core vesicles, not by defective synaptic vesicle release. (Also see the companion article by Edwards et al. in this issue.) Small guanosine triphosphatases of the Rab family regulate intracellular vesicular trafficking. Rab2 is highly expressed in the nervous system, yet its function in neurons is unknown. In Caenorhabditis elegans, unc-108/rab-2 mutants have been isolated based on their locomotory defects. We show that the locomotion defects of rab-2 mutants are not caused by defects in synaptic vesicle release but by defects in dense core vesicle (DCV) signaling. DCVs in rab-2 mutants are often enlarged and heterogeneous in size; however, their number and distribution are not affected. This implicates Rab2 in the biogenesis of DCVs at the Golgi complex. We demonstrate that Rab2 is required to prevent DCV cargo from inappropriately entering late endosomal compartments during DCV maturation. Finally, we show that RIC-19, the C. elegans orthologue of the human diabetes autoantigen ICA69, is also involved in DCV maturation and is recruited to Golgi membranes by activated RAB-2. Thus, we propose that RAB-2 and its effector RIC-19 are required for neuronal DCV maturation.
Collapse
Affiliation(s)
- Marija Sumakovic
- European Neuroscience Institute Goettingen, German Research Foundation Research Center for Molecular Physiology of the Brain, 37077 Goettingen, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Zhang X, Wang G, Dupré DJ, Feng Y, Robitaille M, Lazartigues E, Feng YH, Hébert TE, Wu G. Rab1 GTPase and dimerization in the cell surface expression of angiotensin II type 2 receptor. J Pharmacol Exp Ther 2009; 330:109-17. [PMID: 19357319 DOI: 10.1124/jpet.109.153460] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The physiological function of angiotensin II (Ang II) is mediated through the Ang II type 1 (AT1R) and type 2 (AT2R) receptors. Our previous studies have demonstrated that cell surface targeting of AT1R is regulated by Rab and Sar1 GTPases and the F(x)(6)LL motif in the membrane-proximal C terminus. However, the molecular mechanisms underlying the export of nascent AT2R remain poorly defined. In this report, we determined the role of Rab1 GTPase, which specifically controls protein transport from the endoplasmic reticulum (ER) to the Golgi, and receptor dimerization in the biosynthesis of AT2R. Cell surface expression of AT2R was augmented by transient expression of Rab1 and attenuated by dominant-negative Rab1 mutants and small interfering RNA-mediated knockdown of Rab1. Consistently, AT2R inhibition of epidermal growth factor-activated extracellular signal-regulated kinase 1/2 was significantly reduced by the Rab1 mutants, indicating that endogenous Rab1 modulates the cell surface targeting and signaling of AT2R. It is of interest to note that Rab1 augmented the overall expression of AT2R and its mRNA, whereas the Rab1 mutants attenuated the total AT2R expression and enhanced ubiquitin-dependent AT2R degradation. Furthermore, our previously characterized ER export-deficient AT1R mutant in which the F(x)(6)LL motif was mutated formed both homodimers and heterodimers with AT2R. Dimerization of the AT1R mutant with AT2R blocked AT2R trafficking to the cell surface, suggesting constitutive dimerization of both receptors in the ER and an important role of dimerization in ER export of the receptors. These data demonstrate for the first time that Rab1 GTPase and dimerization modulate export traffic from the ER to the cell surface of newly synthesized AT2R.
Collapse
Affiliation(s)
- Xiaoping Zhang
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, 1901 Perdido St., New Orleans, LA 70112, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Zhang H, Lian C, Shen Z. Proteomic identification of small, copper-responsive proteins in germinating embryos of Oryza sativa. ANNALS OF BOTANY 2009; 103:923-30. [PMID: 19201764 PMCID: PMC2707895 DOI: 10.1093/aob/mcp012] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
BACKGROUND AND AIMS Although copper (Cu) is an essential micronutrient for plants and algae, excess Cu is toxic to most plants and can cause a wide range of deleterious effects. To investigate the response of rice (Oryza sativa) to Cu stress, a proteomic approach was used to analyse Cu stress-induced changes in the expression of low molecular-weight proteins in germinating rice seed embryos. METHODS Rice seeds were germinated in the presence or absence of 200 microm Cu for 6 d, and embryos, including newly formed shoots and radicles, were isolated. After proteins were extracted from the germinating embryos and separated by two-dimensional PAGE, 16 proteins in the 6- to 25-kDa range were identified using MALDI-TOF mass spectrometry. KEY RESULTS AND CONCLUSIONS Thirteen of the proteins identified, including metallothionein-like protein, membrane-associated protein-like protein, putative wall-associated protein kinase, pathogenesis-related proteins and the putative small GTP-binding protein Rab2, were up-regulated by Cu stress. Three proteins, a putative small cytochrome P450 (CYP90D2), a putative thioredoxin and a putative GTPase, were down-regulated by Cu stress. As far as is known, this study provides the first proteomic evidence that metallothionein and CYP90D2 are Cu-responsive proteins in plants. These findings may lead to a better understanding of plant molecular responses to toxic metal exposure.
Collapse
Affiliation(s)
- Hongxiao Zhang
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Chunlan Lian
- Asian Natural Environmental Science Center, The University of Tokyo, 1-1-8 Midori-cho, Nishitokyo, Tokyo 188-0002, Japan
| | - Zhenguo Shen
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
- For correspondence. E-mail
| |
Collapse
|
44
|
Duvernay MT, Dong C, Zhang X, Robitaille M, Hébert TE, Wu G. A single conserved leucine residue on the first intracellular loop regulates ER export of G protein-coupled receptors. Traffic 2009; 10:552-66. [PMID: 19220814 DOI: 10.1111/j.1600-0854.2009.00890.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The intrinsic structural determinants for export trafficking of G protein-coupled receptors (GPCRs) have been mainly identified in the termini of the receptors. In this report, we determined the role of the first intracellular loop (ICL1) in the transport from the endoplasmic reticulum (ER) to the cell surface of GPCRs. The alpha(2B)-adrenergic receptor (AR) mutant lacking the ICL1 is unable to traffic to the cell surface and to initiate signaling measured as ERK1/2 activation. Mutagenesis studies identify a single Leu48 residue in the ICL1 modulates alpha(2B)-AR export from the ER. The ER export function of the Leu48 residue can be substituted by Phe, but not Ile, Val, Tyr and Trp, and is unlikely involved in correct folding or dimerization of alpha(2B)-AR in the ER. Importantly, the isolated Leu residue is remarkably conserved in the center of the ICL1s among the family A GPCRs and is also required for the export to the cell surface of beta(2)-AR, alpha(1B)-AR and angiotensin II type 1 receptor. These data indicate a crucial role for a single Leu residue within the ICL1 in ER export of GPCRs.
Collapse
Affiliation(s)
- Matthew T Duvernay
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, 1901 Perdido St, New Orleans, LA 70112, USA
| | | | | | | | | | | |
Collapse
|
45
|
Current World Literature. Curr Opin Nephrol Hypertens 2009; 18:91-3. [DOI: 10.1097/mnh.0b013e32831fd875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
46
|
Duvernay MT, Dong C, Zhang X, Zhou F, Nichols CD, Wu G. Anterograde trafficking of G protein-coupled receptors: function of the C-terminal F(X)6LL motif in export from the endoplasmic reticulum. Mol Pharmacol 2008; 75:751-61. [PMID: 19118123 DOI: 10.1124/mol.108.051623] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
We have reported previously that the F(X)(6)LL motif in the C termini is essential for export of alpha(2B)-adrenergic (alpha(2B)-AR) and angiotensin II type 1 receptors (AT1Rs) from the endoplasmic reticulum (ER). Here, we further demonstrate that mutation of the F(X)(6)LL motif similarly abolished the cell-surface expression of alpha(2B)-AR, AT1R, alpha(1B)-AR, and beta(2)-AR, suggesting that the F(X)(6)LL motif plays a general role in ER export of G protein-coupled receptors (GPCRs). Mutation of Phe to Val, Leu, Trp, and Tyr, and mutation of LL to FF and VV, markedly inhibited alpha(2B)-AR transport, indicating that the F(X)(6)LL function cannot be fully substituted by other hydrophobic residues. The structural analysis revealed that the Phe residue in the F(X)(6)LL motif is buried in the transmembrane domains and possibly interacts with Ile58 in beta(2)-AR and Val42 in alpha(2B)-AR, whereas the LL motif is exposed to the cytosolic space. Indeed, mutation of Ile58 in beta(2)-AR and Val42 in alpha(2B)-AR markedly disrupted cell surface transport of the receptors. It is noteworthy that the Val and Ile residues are highly conserved among the GPCRs carrying the F(X)(6)LL motif. Furthermore, the Phe mutant exhibited a stronger interaction with ER chaperones and was more potently rescued by physical and chemical treatments than the LL mutant. These data suggest that the Phe residue is probably involved in folding of alpha(2B)-AR and beta(2)-AR, possibly through interaction with other hydrophobic residues in neighboring domains. These data also provide the first evidence implying crucial roles of the C termini possibly through modulating multiple events in anterograde trafficking of GPCRs.
Collapse
Affiliation(s)
- Matthew T Duvernay
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | | | | | | | | | | |
Collapse
|
47
|
An escort for GPCRs: implications for regulation of receptor density at the cell surface. Trends Pharmacol Sci 2008; 29:528-35. [DOI: 10.1016/j.tips.2008.07.009] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Revised: 07/21/2008] [Accepted: 07/22/2008] [Indexed: 12/23/2022]
|
48
|
Dong C, Zhou F, Fugetta EK, Filipeanu CM, Wu G. Endoplasmic reticulum export of adrenergic and angiotensin II receptors is differentially regulated by Sar1 GTPase. Cell Signal 2008; 20:1035-43. [PMID: 18378118 DOI: 10.1016/j.cellsig.2008.01.014] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2007] [Revised: 01/03/2008] [Accepted: 01/04/2008] [Indexed: 10/22/2022]
Abstract
The molecular mechanism underlying the export of G protein-coupled receptors (GPCRs) from the endoplasmic reticulum (ER) remains largely unknown. In this manuscript, we investigated the role of Sar1 GTPase, which coordinates the assembly and budding of COPII-coated vesicles, in the cell-surface targeting, signaling and ER export of alpha(2B)-adrenergic (alpha(2B)-AR), beta(2)-AR and angiotensin II type 1 receptors (AT1R). The cell-surface expression of alpha(2B)-AR, beta(2)-AR and AT1R, and receptor-mediated ERK1/2 activation were significantly attenuated by the GTP-bound mutant Sar1H79G, suggesting that export from the ER of these receptors is mediated through the Sar1-dependent COPII-coated vesicles. Interestingly, subcellular distribution analyses showed that alpha(2B)-AR and AT1R were highly concentrated at discrete locations near the nucleus in cells expressing Sar1H79G, whereas beta(2)-AR exhibited an ER distribution. These data indicate that Sar1-catalyzed efficient GTP hydrolysis differentially regulates ER export of adrenergic and angiotensin II receptors. These data provide the first evidence indicating distinct mechanisms for the recruitment of different GPCRs into the COPII vesicles on the ER membrane.
Collapse
Affiliation(s)
- Chunmin Dong
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, 1901 Perdido St., New Orleans, LA 70112, United States
| | | | | | | | | |
Collapse
|