1
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Zhang Q, Sjögren B. Palmitoylation of RGS20 affects Gα o-mediated signaling independent of its GAP activity. Cell Signal 2023; 107:110682. [PMID: 37075876 DOI: 10.1016/j.cellsig.2023.110682] [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: 09/13/2022] [Revised: 04/07/2023] [Accepted: 04/15/2023] [Indexed: 04/21/2023]
Abstract
Regulator of protein signaling (RGS20) is a member of the RGS protein superfamily, which serve as key negative regulators of G protein-mediated signal transduction. Through their GTPase accelerating protein (GAP) activity, RGS proteins deactivate α-subunits of heterotrimeric G proteins. In addition, the majority of RGS proteins also have the ability to act through other, non-GAP related, functions. RGS20 is one of three members of the RZ subfamily, which all show selective GAP activity towards Gαz, however emerging data suggest that RGS20 can also regulate Gi/o-mediated signaling. While increased RGS20 expression is associated with the progression of multiple cancers, a large gap still exists relating to the mechanisms of RGS20 regulation and function. RGS20 contains a poly-cysteine string motif and a conserved cysteine in RGS domain, which are assumed to be palmitoylated. Palmitoylation, an important post-translational modification, plays an important role in cells by changing cellular functions of proteins. Consequently, the aim of this study was to confirm that RGS20 is palmitoylated and determine how palmitoylation affects its inhibition of Gαo-mediated signaling. We found a significant positive correlation between RGS20 palmitoylation and its association with active Gαo. We also showed that a conserved cysteine residue in the RGS domain is a critical site for its palmitoylation, with large impact on its association with Gαo. Palmitoylation on this site did not affect its GAP activity, however, it increased the inhibition of Gαo-mediated cAMP signaling. Altogether these data suggest that palmitoylation is a regulatory mechanism controlling RGS20 function, and that RGS20 can inhibit Gαo signaling through both GAP activity and non-GAP mechanisms.
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Affiliation(s)
- Qian Zhang
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, United States of America
| | - Benita Sjögren
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, United States of America.
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2
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Abstract
DHHC3 is a DHHC-family palmitoyl acyltransferase that is responsible for many mammalian palmitoylation events. By regulating the posttranslational modification of its specific substrates, DHHC3 has shown a strong protumor effect in various cancers. In this review, the authors introduce the research progress of DHHC3 as a new antitumor target through the expression of DHHC3 in patients with tumors, substrate proteins and potential mechanisms. Recent advances in the search for protein structures and inhibitors are also reviewed. Several design strategies to facilitate the optimization of the process of drug design based on DHHC3 are also discussed.
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3
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Guns J, Vanherle S, Hendriks JJA, Bogie JFJ. Protein Lipidation by Palmitate Controls Macrophage Function. Cells 2022; 11:cells11030565. [PMID: 35159374 PMCID: PMC8834383 DOI: 10.3390/cells11030565] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 02/03/2022] [Accepted: 02/04/2022] [Indexed: 01/27/2023] Open
Abstract
Macrophages are present in all tissues within our body, where they promote tissue homeostasis by responding to microenvironmental triggers, not only through clearance of pathogens and apoptotic cells but also via trophic, regulatory, and repair functions. To accomplish these divergent functions, tremendous dynamic fine-tuning of their physiology is needed. Emerging evidence indicates that S-palmitoylation, a reversible post-translational modification that involves the linkage of the saturated fatty acid palmitate to protein cysteine residues, directs many aspects of macrophage physiology in health and disease. By controlling protein activity, stability, trafficking, and protein–protein interactions, studies identified a key role of S-palmitoylation in endocytosis, inflammatory signaling, chemotaxis, and lysosomal function. Here, we provide an in-depth overview of the impact of S-palmitoylation on these cellular processes in macrophages in health and disease. Findings discussed in this review highlight the therapeutic potential of modulators of S-palmitoylation in immunopathologies, ranging from infectious and chronic inflammatory disorders to metabolic conditions.
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Affiliation(s)
- Jeroen Guns
- Department of Immunology and Infection, Biomedical Research Institute, Hasselt University, 3590 Diepenbeek, Belgium; (J.G.); (S.V.); (J.J.A.H.)
- University MS Center, Hasselt University, 3500 Hasselt, Belgium
| | - Sam Vanherle
- Department of Immunology and Infection, Biomedical Research Institute, Hasselt University, 3590 Diepenbeek, Belgium; (J.G.); (S.V.); (J.J.A.H.)
- University MS Center, Hasselt University, 3500 Hasselt, Belgium
| | - Jerome J. A. Hendriks
- Department of Immunology and Infection, Biomedical Research Institute, Hasselt University, 3590 Diepenbeek, Belgium; (J.G.); (S.V.); (J.J.A.H.)
- University MS Center, Hasselt University, 3500 Hasselt, Belgium
| | - Jeroen F. J. Bogie
- Department of Immunology and Infection, Biomedical Research Institute, Hasselt University, 3590 Diepenbeek, Belgium; (J.G.); (S.V.); (J.J.A.H.)
- University MS Center, Hasselt University, 3500 Hasselt, Belgium
- Correspondence: ; Tel.: +32-1126-9261
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4
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Cheng WX, Ren Y, Lu MM, Xu LL, Gao JG, Chen D, Kalyani FS, Lv ZY, Chen CX, Ji F, Lin HN, Jin X. Palmitoylation in Crohn’s disease: Current status and future directions. World J Gastroenterol 2021; 27:8201-8215. [PMID: 35068865 PMCID: PMC8717020 DOI: 10.3748/wjg.v27.i48.8201] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 05/08/2021] [Accepted: 12/10/2021] [Indexed: 02/06/2023] Open
Abstract
S-palmitoylation is one of the most common post-translational modifications in nature; however, its importance has been overlooked for decades. Crohn’s disease (CD), a subtype of inflammatory bowel disease (IBD), is an autoimmune disease characterized by chronic inflammation involving the entire gastrointestinal tract. Bowel damage and subsequent disabilities caused by CD are a growing global health issue. Well-acknowledged risk factors for CD include genetic susceptibility, environmental factors, such as a westernized lifestyle, and altered gut microbiota. However, the pathophysiological mechanisms of this disorder are not yet comprehensively understood. With the rapidly increasing global prevalence of CD and the evident role of S-palmitoylation in CD, as recently reported, there is a need to investigate the relationship between CD and S-palmitoylation. In this review, we summarize the concept, detection, and function of S-palmitoylation as well as its potential effects on CD, and provide novel insights into the pathogenesis and treatment of CD.
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Affiliation(s)
- Wei-Xin Cheng
- Department of Gastroenterology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, Zhejiang Province, China
| | - Yue Ren
- Department of Gastroenterology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, Zhejiang Province, China
| | - Miao-Miao Lu
- Department of Gastroenterology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, Zhejiang Province, China
| | - Ling-Ling Xu
- Department of Gastroenterology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, Zhejiang Province, China
| | - Jian-Guo Gao
- Department of Gastroenterology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, Zhejiang Province, China
| | - Dong Chen
- Department of Colorectal Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, Zhejiang Province, China
| | - Farhin Shaheed Kalyani
- Department of Gastroenterology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, Zhejiang Province, China
| | - Zi-Yan Lv
- Wenzhou Medical University Renji College, Wenzhou 325035, Zhejiang Province, China
| | - Chun-Xiao Chen
- Department of Gastroenterology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, Zhejiang Province, China
| | - Feng Ji
- Department of Gastroenterology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, Zhejiang Province, China
| | - He-Ning Lin
- Department of Chemistry and Chemical Biology, Howard Hughes Medical Institute, Cornell University, Ithaca, NY 14853, United States
| | - Xi Jin
- Department of Gastroenterology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, Zhejiang Province, China
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5
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Lin H. Protein cysteine palmitoylation in immunity and inflammation. FEBS J 2021; 288:7043-7059. [PMID: 33506611 PMCID: PMC8872633 DOI: 10.1111/febs.15728] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 12/24/2020] [Accepted: 01/25/2021] [Indexed: 07/24/2023]
Abstract
Protein cysteine palmitoylation, or S-palmitoylation, has been known for about 40 years, and thousands of proteins in humans are known to be modified. Because of the large number of proteins modified, the importance and physiological functions of S-palmitoylation are enormous. However, most of the known physiological functions of S-palmitoylation can be broadly classified into two categories, neurological or immunological. This review provides a summary on the function of S-palmitoylation from the immunological perspective. Several important immune signaling pathways are discussed, including STING, NOD1/2, JAK-STAT in cytokine signaling, T-cell receptor signaling, chemotactic GPCR signaling, apoptosis, phagocytosis, and endothelial and epithelial integrity. This review is not meant to be comprehensive, but rather focuses on specific examples to highlight the versatility of palmitoylation in regulating immune signaling, as well as the potential and challenges of targeting palmitoylation to treat immune diseases.
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Affiliation(s)
- Hening Lin
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
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6
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Sharma C, Yang W, Steen H, Freeman MR, Hemler ME. Antioxidant functions of DHHC3 suppress anti-cancer drug activities. Cell Mol Life Sci 2020; 78:2341-2353. [PMID: 32986127 DOI: 10.1007/s00018-020-03635-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 08/11/2020] [Accepted: 09/03/2020] [Indexed: 02/07/2023]
Abstract
Ablation of protein acyltransferase DHHC3 selectively enhanced the anti-cancer cell activities of several chemotherapeutic agents, but not kinase inhibitors. To understand why this occurs, we used comparative mass spectrometry-based palmitoyl-proteomic analysis of breast and prostate cancer cell lines, ± DHHC3 ablation, to obtain the first comprehensive lists of candidate protein substrates palmitoylated by DHHC3. Putative substrates included 22-28 antioxidant/redox-regulatory proteins, thus predicting that DHHC3 should have antioxidant functions. Consistent with this, DHHC3 ablation elevated oxidative stress. Furthermore, DHHC3 ablation, together with chemotherapeutic drug treatment, (a) elevated oxidative stress, with a greater than additive effect, and (b) enhanced the anti-growth effects of the chemotherapeutic agents. These results suggest that DHHC3 ablation enhances chemotherapeutic drug potency by disabling the antioxidant protections that contribute to drug resistance. Affirming this concept, DHHC3 ablation synergized with another anti-cancer drug, PARP inhibitor PJ-34, to decrease cell proliferation and increase oxidative stress. Hence, DHHC3 targeting can be a useful strategy for selectively enhancing potency of oxidative stress-inducing anti-cancer drugs. Also, comprehensive identification of DHHC3 substrates provides insight into other DHHC3 functions, relevant to in vivo tumor growth modulation.
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Affiliation(s)
- Chandan Sharma
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA.
- Dana-Farber Cancer Institute, Rm SM-520, 450 Brookline Ave, Boston, MA, 02215, USA.
| | - Wei Yang
- Division of Cancer Biology and Therapeutics, Departments of Surgery and Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, 90048, USA
| | - Hanno Steen
- Department of Pathology and Precision Vaccines Program, Boston Children's Hospital, Boston, MA, 02215, USA
| | - Michael R Freeman
- Division of Cancer Biology and Therapeutics, Departments of Surgery and Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, 90048, USA
| | - Martin E Hemler
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA.
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7
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Bastin G, Dissanayake K, Langburt D, Tam ALC, Lee SH, Lachhar K, Heximer SP. RGS4 controls Gαi3-mediated regulation of Bcl-2 phosphorylation on TGN38-containing intracellular membranes. J Cell Sci 2020; 133:jcs241034. [PMID: 32501280 DOI: 10.1242/jcs.241034] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 05/05/2020] [Indexed: 08/31/2023] Open
Abstract
Intracellular pools of the heterotrimeric G-protein α-subunit Gαi3 (encoded by GNAI3) have been shown to promote growth factor signaling, while at the same time inhibiting the activation of JNK and autophagic signaling following nutrient starvation. The precise molecular mechanisms linking Gαi3 to both stress and growth factor signaling remain poorly understood. Importantly, JNK-mediated phosphorylation of Bcl-2 was previously found to activate autophagic signaling following nutrient deprivation. Our data shows that activated Gαi3 decreases Bcl-2 phosphorylation, whereas inhibitors of Gαi3, such as RGS4 and AGS3 (also known as GPSM1), markedly increase the levels of phosphorylated Bcl-2. Manipulation of the palmitoylation status and intracellular localization of RGS4 suggests that Gαi3 modulates phosphorylated Bcl-2 levels and autophagic signaling from discreet TGN38 (also known as TGOLN2)-labeled vesicle pools. Consistent with an important role for these molecules in normal tissue responses to nutrient deprivation, increased Gαi signaling within nutrient-starved adrenal glands from RGS4-knockout mice resulted in a dramatic abrogation of autophagic flux, compared to wild-type tissues. Together, these data suggest that the activity of Gαi3 and RGS4 from discreet TGN38-labeled vesicle pools are critical regulators of autophagic signaling that act via their ability to modulate phosphorylation of Bcl-2.
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Affiliation(s)
- Guillaume Bastin
- Ted Rogers Centre for Heart Research, Translational Biology and Engineering Program, 661 University Ave. 14th Floor, Toronto, ON, M5G 1M1, Canada
- Heart and Stroke/Richard Lewar Centre of Excellence in Cardiovascular Research, Room 303, C. David Naylor Building, 6 Queen's Park Crescent West, Toronto, ON, M5S 3H2, Canada
- Department of Physiology, University of Toronto, 1 King's College Circle, Toronto, ON, M5S1A8, Canada
| | - Kaveesh Dissanayake
- Department of Physiology, University of Toronto, 1 King's College Circle, Toronto, ON, M5S1A8, Canada
| | - Dylan Langburt
- Ted Rogers Centre for Heart Research, Translational Biology and Engineering Program, 661 University Ave. 14th Floor, Toronto, ON, M5G 1M1, Canada
- Department of Physiology, University of Toronto, 1 King's College Circle, Toronto, ON, M5S1A8, Canada
| | - Alex L C Tam
- Department of Physiology, University of Toronto, 1 King's College Circle, Toronto, ON, M5S1A8, Canada
| | - Shin-Haw Lee
- Ted Rogers Centre for Heart Research, Translational Biology and Engineering Program, 661 University Ave. 14th Floor, Toronto, ON, M5G 1M1, Canada
- Department of Physiology, University of Toronto, 1 King's College Circle, Toronto, ON, M5S1A8, Canada
| | - Karanjit Lachhar
- Department of Physiology, University of Toronto, 1 King's College Circle, Toronto, ON, M5S1A8, Canada
| | - Scott P Heximer
- Ted Rogers Centre for Heart Research, Translational Biology and Engineering Program, 661 University Ave. 14th Floor, Toronto, ON, M5G 1M1, Canada
- Heart and Stroke/Richard Lewar Centre of Excellence in Cardiovascular Research, Room 303, C. David Naylor Building, 6 Queen's Park Crescent West, Toronto, ON, M5S 3H2, Canada
- Department of Physiology, University of Toronto, 1 King's College Circle, Toronto, ON, M5S1A8, Canada
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8
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De I, Sadhukhan S. Emerging Roles of DHHC-mediated Protein S-palmitoylation in Physiological and Pathophysiological Context. Eur J Cell Biol 2018; 97:319-338. [DOI: 10.1016/j.ejcb.2018.03.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 03/14/2018] [Accepted: 03/16/2018] [Indexed: 02/08/2023] Open
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9
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Madigan LA, Wong GS, Gordon EM, Chen WS, Balenga N, Koziol-White CJ, Panettieri RA, Levine SJ, Druey KM. RGS4 Overexpression in Lung Attenuates Airway Hyperresponsiveness in Mice. Am J Respir Cell Mol Biol 2018; 58:89-98. [PMID: 28853915 DOI: 10.1165/rcmb.2017-0109oc] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A cardinal feature of asthma is airway hyperresponsiveness (AHR) to spasmogens, many of which activate G protein-coupled receptors (GPCRs) on airway smooth muscle (ASM) cells. Asthma subtypes associated with allergy are characterized by eosinophilic inflammation in the lung due to the type 2 immune response to allergens and proinflammatory mediators that promote AHR. The degree to which intrinsic abnormalities of ASM contribute to this phenotype remains unknown. The regulators of G protein signaling (RGS) proteins are a large group of intracellular proteins that inhibit GPCR signaling pathways. RGS2- and RGS5-deficient mice develop AHR spontaneously. Although RGS4 is upregulated in ASM from patients with severe asthma, the effects of increased RGS4 expression on AHR in vivo are unknown. Here, we examined the impact of forced RGS4 overexpression in lung on AHR using transgenic (Tg) mice. Tg RGS4 was expressed in bronchial epithelium and ASM in vivo, and protein expression in lung was increased at least 4-fold in Tg mice compared with wild-type (WT) mice. Lung slices from Tg mice contracted less in response to the m3 muscarinic receptor agonist methacholine compared with the WT, although airway resistance in live, unchallenged mice of both strains was similar. Tg mice were partially protected against AHR induced by fungal allergen challenge due to weakened contraction signaling in ASM and reduced type 2 cytokine (IL-5 and IL-13) levels in Tg mice compared with the WT. These results provide support for the hypothesis that increasing RGS4 expression and/or function could be a viable therapeutic strategy for asthma.
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Affiliation(s)
- Laura A Madigan
- 1 Molecular Signal Transduction Section, Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, and
| | - Gordon S Wong
- 1 Molecular Signal Transduction Section, Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, and
| | - Elizabeth M Gordon
- 2 Laboratory of Asthma and Lung Inflammation, Cardiovascular and Pulmonary Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland; and
| | - Wei-Sheng Chen
- 1 Molecular Signal Transduction Section, Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, and
| | - Nariman Balenga
- 1 Molecular Signal Transduction Section, Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, and
| | - Cynthia J Koziol-White
- 3 Rutgers Institute for Translational Medicine and Science, Child Health Institute, Rutgers University, New Brunswick, New Jersey
| | - Reynold A Panettieri
- 3 Rutgers Institute for Translational Medicine and Science, Child Health Institute, Rutgers University, New Brunswick, New Jersey
| | - Stewart J Levine
- 2 Laboratory of Asthma and Lung Inflammation, Cardiovascular and Pulmonary Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland; and
| | - Kirk M Druey
- 1 Molecular Signal Transduction Section, Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, and
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10
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Jiang H, Zhang X, Chen X, Aramsangtienchai P, Tong Z, Lin H. Protein Lipidation: Occurrence, Mechanisms, Biological Functions, and Enabling Technologies. Chem Rev 2018; 118:919-988. [PMID: 29292991 DOI: 10.1021/acs.chemrev.6b00750] [Citation(s) in RCA: 283] [Impact Index Per Article: 47.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Protein lipidation, including cysteine prenylation, N-terminal glycine myristoylation, cysteine palmitoylation, and serine and lysine fatty acylation, occurs in many proteins in eukaryotic cells and regulates numerous biological pathways, such as membrane trafficking, protein secretion, signal transduction, and apoptosis. We provide a comprehensive review of protein lipidation, including descriptions of proteins known to be modified and the functions of the modifications, the enzymes that control them, and the tools and technologies developed to study them. We also highlight key questions about protein lipidation that remain to be answered, the challenges associated with answering such questions, and possible solutions to overcome these challenges.
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Affiliation(s)
- Hong Jiang
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Xiaoyu Zhang
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Xiao Chen
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Pornpun Aramsangtienchai
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Zhen Tong
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Hening Lin
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
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11
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Sharma C, Wang HX, Li Q, Knoblich K, Reisenbichler ES, Richardson AL, Hemler ME. Protein Acyltransferase DHHC3 Regulates Breast Tumor Growth, Oxidative Stress, and Senescence. Cancer Res 2017; 77:6880-6890. [PMID: 29055014 DOI: 10.1158/0008-5472.can-17-1536] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 08/29/2017] [Accepted: 10/17/2017] [Indexed: 01/03/2023]
Abstract
DHHC-type protein acyltransferases may regulate the localization, stability, and/or activity of their substrates. In this study, we show that the protein palmitoyltransferase DHHC3 is upregulated in malignant and metastatic human breast cancer. Elevated expression of DHHC3 correlated with diminished patient survival in breast cancer and six other human cancer types. ZDHHC3 ablation in human MDA-MB-231 mammary tumor cell xenografts reduced the sizes of both the primary tumor and metastatic lung colonies. Gene array data and fluorescence dye assays documented increased oxidative stress and senescence in ZDHHC3-ablated cells. ZDHHC3-ablated tumors also showed enhanced recruitment of innate immune cells (antitumor macrophages, natural killer cells) associated with clearance of senescent tumors. These antitumor effects were reversed upon reconstitution with wild-type, but not enzyme-active site-deficient DHHC3. Concomitant ablation of the upregulated oxidative stress protein TXNIP substantially negated the effects of ZDHHC3 depletion on oxidative stress and senescence. Diminished DHHC3-dependent palmitoylation of ERGIC3 protein likely played a key role in TXNIP upregulation. In conclusion, DHHC3-mediated protein palmitoylation supports breast tumor growth by modulating cellular oxidative stress and senescence. Cancer Res; 77(24); 6880-90. ©2017 AACR.
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Affiliation(s)
- Chandan Sharma
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute and Department of Pathology, Harvard Medical School, Boston, Massachusetts
| | - Hong-Xing Wang
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute and Department of Pathology, Harvard Medical School, Boston, Massachusetts
| | - Qinglin Li
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute and Department of Pathology, Harvard Medical School, Boston, Massachusetts
| | - Konstantin Knoblich
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute and Department of Pathology, Harvard Medical School, Boston, Massachusetts
| | - Emily S Reisenbichler
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute and Department of Pathology, Harvard Medical School, Boston, Massachusetts
| | - Andrea L Richardson
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute and Department of Pathology, Harvard Medical School, Boston, Massachusetts
| | - Martin E Hemler
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute and Department of Pathology, Harvard Medical School, Boston, Massachusetts.
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12
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Alqinyah M, Hooks SB. Regulating the regulators: Epigenetic, transcriptional, and post-translational regulation of RGS proteins. Cell Signal 2017; 42:77-87. [PMID: 29042285 DOI: 10.1016/j.cellsig.2017.10.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 10/06/2017] [Accepted: 10/13/2017] [Indexed: 12/11/2022]
Abstract
Regulators of G protein signaling (RGS) are a family of proteins classically known to accelerate the intrinsic GTPase activity of G proteins, which results in accelerated inactivation of heterotrimeric G proteins and inhibition of G protein coupled receptor signaling. RGS proteins play major roles in essential cellular processes, and dysregulation of RGS protein expression is implicated in multiple diseases, including cancer, cardiovascular and neurodegenerative diseases. The expression of RGS proteins is highly dynamic and is regulated by epigenetic, transcriptional and post-translational mechanisms. This review summarizes studies that report dysregulation of RGS protein expression in disease states, and presents examples of drugs that regulate RGS protein expression. Additionally, this review discusses, in detail, the transcriptional and post-transcriptional mechanisms regulating RGS protein expression, and further assesses the therapeutic potential of targeting these mechanisms. Understanding the molecular mechanisms controlling the expression of RGS proteins is essential for the development of therapeutics that indirectly modulate G protein signaling by regulating expression of RGS proteins.
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Affiliation(s)
- Mohammed Alqinyah
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA, USA
| | - Shelley B Hooks
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA, USA.
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13
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Protein S-palmitoylation and cancer. Biochim Biophys Acta Rev Cancer 2015; 1856:107-20. [PMID: 26112306 DOI: 10.1016/j.bbcan.2015.06.004] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 06/16/2015] [Accepted: 06/21/2015] [Indexed: 12/16/2022]
Abstract
Protein S-palmitoylation is a reversible posttranslational modification of proteins with fatty acids, an enzymatic process driven by a recently discovered family of protein acyltransferases (PATs) that are defined by a conserved catalytic domain characterized by a DHHC sequence motif. Protein S-palmitoylation has a prominent role in regulating protein location, trafficking and function. Recent studies of DHHC PATs and their functional effects have demonstrated that their dysregulation is associated with human diseases, including schizophrenia, X-linked mental retardation, and Huntington's Disease. A growing number of reports indicate an important role for DHHC proteins and their substrates in tumorigenesis. Whereas DHHC PATs comprise a family of 23 enzymes in humans, a smaller number of enzymes that remove palmitate have been identified and characterized as potential therapeutic targets. Here we review current knowledge of the enzymes that mediate reversible palmitoylation and their cancer-associated substrates and discuss potential therapeutic applications.
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14
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Ganss R. Keeping the Balance Right. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 133:93-121. [DOI: 10.1016/bs.pmbts.2015.02.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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15
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Stable expression and function of the inositol 1,4,5-triphosphate receptor requires palmitoylation by a DHHC6/selenoprotein K complex. Proc Natl Acad Sci U S A 2014; 111:16478-83. [PMID: 25368151 DOI: 10.1073/pnas.1417176111] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Calcium (Ca(2+)) is a secondary messenger in cells and Ca(2+) flux initiated from endoplasmic reticulum (ER) stores via inositol 1,4,5-triphosphate (IP3) binding to the IP3 receptor (IP3R) is particularly important for the activation and function of immune cells. Previous studies demonstrated that genetic deletion of selenoprotein K (Selk) led to decreased Ca(2+) flux in a variety of immune cells and impaired immunity, but the mechanism was unclear. Here we show that Selk deficiency does not affect receptor-induced IP3 production, but Selk deficiency through genetic deletion or low selenium in culture media leads to low expression of the IP3R due to a defect in IP3R palmitoylation. Bioinformatic analysis of the DHHC (letters represent the amino acids aspartic acid, histidine, histidine, and cysteine in the catalytic domain) family of enzymes that catalyze protein palmitoylation revealed that one member, DHHC6, contains a predicted Src-homology 3 (SH3) domain and DHHC6 is localized to the ER membrane. Because Selk is also an ER membrane protein and contains an SH3 binding domain, immunofluorescence and coimmunoprecipitation experiments were conducted and revealed DHHC6/Selk interactions in the ER membrane that depended on SH3/SH3 binding domain interactions. DHHC6 knockdown using shRNA in stably transfected cell lines led to decreased expression of the IP3R and impaired IP3R-dependent Ca(2+) flux. Mass spectrophotometric and bioinformatic analyses of the IP3R protein identified two palmitoylated cysteine residues and another potentially palmitoylated cysteine, and mutation of these three cysteines to alanines resulted in decreased IP3R palmitoylation and function. These findings reveal IP3R palmitoylation as a critical regulator of Ca(2+) flux in immune cells and define a previously unidentified DHHC/Selk complex responsible for this process.
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Chen IS, Furutani K, Inanobe A, Kurachi Y. RGS4 regulates partial agonism of the M2 muscarinic receptor-activated K+ currents. J Physiol 2014; 592:1237-48. [PMID: 24421355 PMCID: PMC3961084 DOI: 10.1113/jphysiol.2013.269803] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 01/07/2014] [Indexed: 12/20/2022] Open
Abstract
Partial agonists are used clinically to avoid overstimulation of receptor-mediated signalling, as they produce a submaximal response even at 100% receptor occupancy. The submaximal efficacy of partial agonists is due to conformational change of the agonist-receptor complex, which reduces effector activation. In addition to signalling activators, several regulators help control intracellular signal transductions. However, it remains unclear whether these signalling regulators contribute to partial agonism. Here we show that regulator of G-protein signalling (RGS) 4 is a determinant for partial agonism of the M2 muscarinic receptor (M2R). In rat atrial myocytes, pilocarpine evoked smaller G-protein-gated K(+) inwardly rectifying (KG) currents than those evoked by ACh. In a Xenopus oocyte expression system, pilocarpine acted as a partial agonist in the presence of RGS4 as it did in atrial myocytes, while it acted like a full agonist in the absence of RGS4. Functional couplings within the agonist-receptor complex/G-protein/RGS4 system controlled the efficacy of pilocarpine relative to ACh. The pilocarpine-M2R complex suppressed G-protein-mediated activation of KG currents via RGS4. Our results demonstrate that partial agonism of M2R is regulated by the RGS4-mediated inhibition of G-protein signalling. This finding helps us to understand the molecular components and mechanism underlying the partial agonism of M2R-mediated physiological responses.
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Affiliation(s)
- I-Shan Chen
- Department of Pharmacology, Graduate School of MedicineJapan
| | - Kazuharu Furutani
- Department of Pharmacology, Graduate School of MedicineJapan
- Center for Advanced Medical Engineering and Informatics, Osaka UniversityJapan
| | - Atsushi Inanobe
- Department of Pharmacology, Graduate School of MedicineJapan
- Center for Advanced Medical Engineering and Informatics, Osaka UniversityJapan
| | - Yoshihisa Kurachi
- Department of Pharmacology, Graduate School of MedicineJapan
- Center for Advanced Medical Engineering and Informatics, Osaka UniversityJapan
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Sharma C, Rabinovitz I, Hemler ME. Palmitoylation by DHHC3 is critical for the function, expression, and stability of integrin α6β4. Cell Mol Life Sci 2012; 69:2233-44. [PMID: 22314500 DOI: 10.1007/s00018-012-0924-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Revised: 01/05/2012] [Accepted: 01/19/2012] [Indexed: 12/14/2022]
Abstract
The laminin-binding integrin α6β4 plays key roles in both normal epithelial and endothelial cells and during tumor cell progression, metastasis, and angiogenesis. Previous cysteine mutagenesis studies have suggested that palmitoylation of α6β4 protein supports a few integrin-dependent functions and molecular associations. Here we took another approach and obtained strikingly different results. We used overexpression and RNAi knockdown in multiple cell types to identify protein acyl transferase DHHC3 as the enzyme responsible for integrin β4 and α6 palmitoylation. Ablation of DHHC3 markedly diminished integrin-dependent cellular cable formation on Matrigel, integrin signaling through Src, and β4 phosphorylation on key diagnostic amino acids (S1356 and 1424). However, unexpectedly, and in sharp contrast to prior α6β4 mutagenesis results, knockdown of DHHC3 accelerated the degradation of α6β4, likely due to an increase in endosomal exposure to cathepsin D. When proteolytic degradation was inhibited (by Pepstatin A), rescued α6β4 accumulated intracellularly, but was unable to reach the cell surface. DHHC3 ablation effects were strongly selective for α6β4. Cell-surface levels of ~10 other proteins (including α3β1) were not diminished, and the appearance of hundreds of other palmitoylated proteins was not altered. Results obtained here demonstrate a new substrate for the DHHC3 enzyme and provide novel opportunities for modulating α6β4 expression, distribution, and function.
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Affiliation(s)
- Chandan Sharma
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Boston, MA 02215, USA
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Bastin G, Singh K, Dissanayake K, Mighiu AS, Nurmohamed A, Heximer SP. Amino-terminal cysteine residues differentially influence RGS4 protein plasma membrane targeting, intracellular trafficking, and function. J Biol Chem 2012; 287:28966-74. [PMID: 22753418 DOI: 10.1074/jbc.m112.345629] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Regulator of G-protein signaling (RGS) proteins are potent inhibitors of heterotrimeric G-protein signaling. RGS4 attenuates G-protein activity in several tissues. Previous work demonstrated that cysteine palmitoylation on residues in the amino-terminal (Cys-2 and Cys-12) and core domains (Cys-95) of RGS4 is important for protein stability, plasma membrane targeting, and GTPase activating function. To date Cys-2 has been the priority target for RGS4 regulation by palmitoylation based on its putative role in stabilizing the RGS4 protein. Here, we investigate differences in the contribution of Cys-2 and Cys-12 to the intracellular localization and function of RGS4. Inhibition of RGS4 palmitoylation with 2-bromopalmitate dramatically reduced its localization to the plasma membrane. Similarly, mutation of the RGS4 amphipathic helix (L23D) prevented membrane localization and its G(q) inhibitory function. Together, these data suggest that both RGS4 palmitoylation and the amphipathic helix domain are required for optimal plasma membrane targeting and function of RGS4. Mutation of Cys-12 decreased RGS4 membrane targeting to a similar extent as 2-bromopalmitate, resulting in complete loss of its G(q) inhibitory function. Mutation of Cys-2 did not impair plasma membrane targeting but did partially impair its function as a G(q) inhibitor. Comparison of the endosomal distribution pattern of wild type and mutant RGS4 proteins with TGN38 indicated that palmitoylation of these two cysteines contributes differentially to the intracellular trafficking of RGS4. These data show for the first time that Cys-2 and Cys-12 play markedly different roles in the regulation of RGS4 membrane localization, intracellular trafficking, and G(q) inhibitory function via mechanisms that are unrelated to RGS4 protein stabilization.
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Affiliation(s)
- Guillaume Bastin
- Department of Physiology, Heart and Stroke/Richard Lewar Centre of Excellence in Cardiovascular Research, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
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Kach J, Sethakorn N, Dulin NO. A finer tuning of G-protein signaling through regulated control of RGS proteins. Am J Physiol Heart Circ Physiol 2012; 303:H19-35. [PMID: 22542620 DOI: 10.1152/ajpheart.00764.2011] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Regulators of G-protein signaling (RGS) proteins are GTPase-activating proteins (GAP) for various Gα subunits of heterotrimeric G proteins. Through this mechanism, RGS proteins regulate the magnitude and duration of G-protein-coupled receptor signaling and are often referred to as fine tuners of G-protein signaling. Increasing evidence suggests that RGS proteins themselves are regulated through multiple mechanisms, which may provide an even finer tuning of G-protein signaling and crosstalk between G-protein-coupled receptors and other signaling pathways. This review summarizes the current data on the control of RGS function through regulated expression, intracellular localization, and covalent modification of RGS proteins, as related to cell function and the pathogenesis of diseases.
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Affiliation(s)
- Jacob Kach
- Department of Medicine, University of Chicago, Illinois, 60637, USA
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MEKK1-MKK4-JNK-AP1 pathway negatively regulates Rgs4 expression in colonic smooth muscle cells. PLoS One 2012; 7:e35646. [PMID: 22545125 PMCID: PMC3335800 DOI: 10.1371/journal.pone.0035646] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Accepted: 03/19/2012] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Regulator of G-protein Signaling 4 (RGS4) plays an important role in regulating smooth muscle contraction, cardiac development, neural plasticity and psychiatric disorder. However, the underlying regulatory mechanisms remain elusive. Our recent studies have shown that upregulation of Rgs4 by interleukin (IL)-1β is mediated by the activation of NFκB signaling and modulated by extracellular signal-regulated kinases, p38 mitogen-activated protein kinase, and phosphoinositide-3 kinase. Here we investigate the effect of the c-Jun N-terminal kinase (JNK) pathway on Rgs4 expression in rabbit colonic smooth muscle cells. METHODOLOGY/PRINCIPAL FINDINGS Cultured cells at first passage were treated with or without IL-1β (10 ng/ml) in the presence or absence of the selective JNK inhibitor (SP600125) or JNK small hairpin RNA (shRNA). The expression levels of Rgs4 mRNA and protein were determined by real-time RT-PCR and Western blot respectively. SP600125 or JNK shRNA increased Rgs4 expression in the absence or presence of IL-1β stimulation. Overexpression of MEKK1, the key upstream kinase of JNK, inhibited Rgs4 expression, which was reversed by co-expression of JNK shRNA or dominant-negative mutants for MKK4 or JNK. Both constitutive and inducible upregulation of Rgs4 expression by SP600125 was significantly inhibited by pretreatment with the transcription inhibitor, actinomycin D. Dual reporter assay showed that pretreatment with SP600125 sensitized the promoter activity of Rgs4 in response to IL-1β. Mutation of the AP1-binding site within Rgs4 promoter increased the promoter activity. Western blot analysis confirmed that IL-1β treatment increased the phosphorylation of JNK, ATF-2 and c-Jun. Gel shift and chromatin immunoprecipitation assays validated that IL-1β increased the in vitro and ex vivo binding activities of AP1 within rabbit Rgs4 promoter. CONCLUSION/SIGNIFICANCE Activation of MEKK1-MKK4-JNK-AP1 signal pathway plays a tonic inhibitory role in regulating Rgs4 transcription in rabbit colonic smooth muscle cells. This negative regulation may aid in maintaining the transient level of RGS4 expression.
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Stewart A, Huang J, Fisher RA. RGS Proteins in Heart: Brakes on the Vagus. Front Physiol 2012; 3:95. [PMID: 22685433 PMCID: PMC3368389 DOI: 10.3389/fphys.2012.00095] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Accepted: 03/27/2012] [Indexed: 12/14/2022] Open
Abstract
It has been nearly a century since Otto Loewi discovered that acetylcholine (ACh) release from the vagus produces bradycardia and reduced cardiac contractility. It is now known that parasympathetic control of the heart is mediated by ACh stimulation of G(i/o)-coupled muscarinic M2 receptors, which directly activate G protein-coupled inwardly rectifying potassium (GIRK) channels via Gβγ resulting in membrane hyperpolarization and inhibition of action potential (AP) firing. However, expression of M2R-GIRK signaling components in heterologous systems failed to recapitulate native channel gating kinetics. The missing link was identified with the discovery of regulator of G protein signaling (RGS) proteins, which act as GTPase-activating proteins to accelerate the intrinsic GTPase activity of Gα resulting in termination of Gα- and Gβγ-mediated signaling to downstream effectors. Studies in mice expressing an RGS-insensitive Gα(i2) mutant (G184S) implicated endogenous RGS proteins as key regulators of parasympathetic signaling in heart. Recently, two RGS proteins have been identified as critical regulators of M2R signaling in heart. RGS6 exhibits a uniquely robust expression in heart, especially in sinoatrial (SAN) and atrioventricular nodal regions. Mice lacking RGS6 exhibit increased bradycardia and inhibition of SAN AP firing in response to CCh as well as a loss of rapid activation and deactivation kinetics and current desensitization for ACh-induced GIRK current (I(KACh)). Similar findings were observed in mice lacking RGS4. Thus, dysregulation in RGS protein expression or function may contribute to pathologies involving aberrant electrical activity in cardiac pacemaker cells. Moreover, RGS6 expression was found to be up-regulated in heart under certain pathological conditions, including doxorubicin treatment, which is known to cause life-threatening cardiotoxicity and atrial fibrillation in cancer patients. On the other hand, increased vagal tone may be cardioprotective in heart failure where acetylcholinesterase inhibitors and vagal stimulation have been proposed as potential therapeutics. Together, these studies identify RGS proteins, especially RGS6, as new therapeutic targets for diseases such as sick sinus syndrome or other maladies involving abnormal autonomic control of the heart.
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Affiliation(s)
- Adele Stewart
- Department of Pharmacology, Carver College of Medicine, University of Iowa Iowa City, IA, USA
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Oh Y, Jeon YJ, Hong GS, Kim I, Woo HN, Jung YK. Regulation in the targeting of TRAIL receptor 1 to cell surface via GODZ for TRAIL sensitivity in tumor cells. Cell Death Differ 2012; 19:1196-207. [PMID: 22240897 DOI: 10.1038/cdd.2011.209] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and its receptors, TRAIL-R1 (DR4) and TRAIL-R2 (DR5), promote the selective clearing of various malignancies by inducing apoptosis, holding the promise as a potent therapeutic agent for anticancer. Though DR4 and DR5 have high sequence similarity, differential regulation of both receptors in human tumor cells remains largely unexplored. Here, we repot that golgi-specific Asp-His-His-Cys (DHHC) zinc finger protein (GODZ) regulates TRAIL/DR4-mediated apoptosis. Using the SOS protein recruitment-yeast two-hybrid screening, we isolated GODZ that interacted with the death domain of DR4. GODZ binds to DR4, but not to DR5, through the DHHC and the C-terminal transmembrane domain. Expression level of GODZ affects apoptosis of tumor cells triggered by TRAIL, but not that induced by TNF-α/cycloheximide (CHX) or DNA-damaging drugs. In parallel, GODZ functions to localize DR4 to the plasma membrane (PM) via DHHC motif. Also, introduction of mutation into the cysteine-rich motif of DR4 results in its mistargeting and attenuates TRAIL- or GODZ-mediated apoptosis. Interestingly, GODZ expression is highly downregulated in Hep-3B tumor cells, which show resistance to TRAIL. However, reconstitution of GODZ expression enhances the targeting of DR4 to cell surface and sensitizes Hep-3B cells to TRAIL. Taken together, these data establish that GODZ is a novel DR4-selective regulator responsible for targeting of DR4 to the PM, and thereby for TRAIL-induced apoptosis.
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Affiliation(s)
- Y Oh
- Global Research Laboratory, School of Biological Science/Bio-Max Institute, Seoul National University, Korea
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Guan X, Fierke CA. Understanding Protein Palmitoylation: Biological Significance and Enzymology. Sci China Chem 2011; 54:1888-1897. [PMID: 25419213 DOI: 10.1007/s11426-011-4428-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Protein palmitoylation is a widespread lipid modification in which one or more cysteine thiols on a substrate protein are modified to form a thioester with a palmitoyl group. This lipid modification is readily reversible; a feature of protein palmitoylation that allows for rapid regulation of the function of many cellular proteins. Mutations in palmitoyltransferases (PATs), the enzymes that catalyze the formation of this modification, are associated with a number of neurological diseases and cancer progression. This review summarizes the crucial role of palmitoylation in biological systems, the discovery of the DHHC protein family that catalyzes protein palmitoylation, and the development of methods for investigating the catalytic mechanism of PATs.
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Affiliation(s)
- Xiaomu Guan
- Departments of Chemistry and Biological Chemistry, University of Michigan, 930 N University, Ann Arbor, MI 48109-1055, USA
| | - Carol A Fierke
- Departments of Chemistry and Biological Chemistry, University of Michigan, 930 N University, Ann Arbor, MI 48109-1055, USA
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Abstract
Signal transduction through G-protein-coupled receptors (GPCRs) is central for the regulation of virtually all cellular functions and has been widely implicated in human disease. Regulators of G-protein signaling (RGS proteins) belong to a diverse protein family that was originally discovered for their ability to accelerate signal termination in response to GPCR stimulation, thereby reducing the amplitude and duration of GPCR effects. All RGS proteins share a common RGS domain that interacts with G protein α subunits and mediates their biological regulation of GPCR signaling. However, RGS proteins differ widely in size and the organization of their sequences flanking the RGS domain, which contain several additional functional domains that facilitate protein-protein (or protein-lipid) interactions. RGS proteins are subject to posttranslational modifications, and, in addition, their expression, activity, and subcellular localization can be dynamically regulated. Thus, there exists a wide array of mechanisms that facilitate their proper function as modulators and integrators of G-protein signaling. Several RGS proteins have been implicated in the cardiac remodeling response and heart rate regulation, and changes in RGS protein expression and/or function are believed to participate in the pathophysiology of cardiac hypertrophy, failure and arrhythmias as well as hypertension. This review is based on recent advances in our understanding of the expression pattern, regulation, and functional role of canonical RGS proteins, with a special focus on the healthy heart and the diseased heart. In addition, we discuss their potential and promise as therapeutic targets as well as strategies to modulate their expression and function.
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Affiliation(s)
- Peng Zhang
- Cardiovascular Research Center, Rhode Island Hospital and Alpert Medical School of Brown University, 1 Hoppin St, Providence, RI 02903, USA
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