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Bo T, Gao L, Yao Z, Shao S, Wang X, Proud CG, Zhao J. Hepatic selective insulin resistance at the intersection of insulin signaling and metabolic dysfunction-associated steatotic liver disease. Cell Metab 2024; 36:947-968. [PMID: 38718757 DOI: 10.1016/j.cmet.2024.04.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 01/22/2024] [Accepted: 04/09/2024] [Indexed: 06/26/2024]
Abstract
Insulin resistance (IR) is a major pathogenic factor in the progression of MASLD. In the liver, insulin suppresses gluconeogenesis and enhances de novo lipogenesis (DNL). During IR, there is a defect in insulin-mediated suppression of gluconeogenesis, but an unrestrained increase in hepatic lipogenesis persists. The mechanism of increased hepatic steatosis in IR is unclear and remains controversial. The key discrepancy is whether insulin retains its ability to directly regulate hepatic lipogenesis. Blocking insulin/IRS/AKT signaling reduces liver lipid deposition in IR, suggesting insulin can still regulate lipid metabolism; hepatic glucose metabolism that bypasses insulin's action may contribute to lipogenesis; and due to peripheral IR, other tissues are likely to impact liver lipid deposition. We here review the current understanding of insulin's action in governing different aspects of hepatic lipid metabolism under normal and IR states, with the purpose of highlighting the essential issues that remain unsettled.
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Affiliation(s)
- Tao Bo
- Key Laboratory of Endocrine Glucose & Lipids Metabolism and Brain Aging, Ministry of Education, Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China; Central Laboratory, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China; Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, China
| | - Ling Gao
- Key Laboratory of Endocrine Glucose & Lipids Metabolism and Brain Aging, Ministry of Education, Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China; Central Laboratory, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China; Shandong Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, Shandong, China
| | - Zhenyu Yao
- Key Laboratory of Endocrine Glucose & Lipids Metabolism and Brain Aging, Ministry of Education, Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China; Shandong Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, Shandong, China
| | - Shanshan Shao
- Key Laboratory of Endocrine Glucose & Lipids Metabolism and Brain Aging, Ministry of Education, Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China; Shandong Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, Shandong, China
| | - Xuemin Wang
- Lifelong Health, South Australian Health & Medical Research Institute, North Terrace, Adelaide, SA, Australia
| | - Christopher G Proud
- Lifelong Health, South Australian Health & Medical Research Institute, North Terrace, Adelaide, SA, Australia.
| | - Jiajun Zhao
- Key Laboratory of Endocrine Glucose & Lipids Metabolism and Brain Aging, Ministry of Education, Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China; Shandong Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, Shandong, China.
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Abu-Toamih-Atamni HJ, Lone IM, Binenbaum I, Mott R, Pilalis E, Chatziioannou A, Iraqi FA. Mapping novel QTL and fine mapping of previously identified QTL associated with glucose tolerance using the collaborative cross mice. Mamm Genome 2024; 35:31-55. [PMID: 37978084 DOI: 10.1007/s00335-023-10025-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Accepted: 10/08/2023] [Indexed: 11/19/2023]
Abstract
A chronic metabolic illness, type 2 diabetes (T2D) is a polygenic and multifactorial complicated disease. With an estimated 463 million persons aged 20 to 79 having diabetes, the number is expected to rise to 700 million by 2045, creating a significant worldwide health burden. Polygenic variants of diabetes are influenced by environmental variables. T2D is regarded as a silent illness that can advance for years before being diagnosed. Finding genetic markers for T2D and metabolic syndrome in groups with similar environmental exposure is therefore essential to understanding the mechanism of such complex characteristic illnesses. So herein, we demonstrated the exclusive use of the collaborative cross (CC) mouse reference population to identify novel quantitative trait loci (QTL) and, subsequently, suggested genes associated with host glucose tolerance in response to a high-fat diet. In this study, we used 539 mice from 60 different CC lines. The diabetogenic effect in response to high-fat dietary challenge was measured by the three-hour intraperitoneal glucose tolerance test (IPGTT) test after 12 weeks of dietary challenge. Data analysis was performed using a statistical software package IBM SPSS Statistic 23. Afterward, blood glucose concentration at the specific and between different time points during the IPGTT assay and the total area under the curve (AUC0-180) of the glucose clearance was computed and utilized as a marker for the presence and severity of diabetes. The observed AUC0-180 averages for males and females were 51,267.5 and 36,537.5 mg/dL, respectively, representing a 1.4-fold difference in favor of females with lower AUC0-180 indicating adequate glucose clearance. The AUC0-180 mean differences between the sexes within each specific CC line varied widely within the CC population. A total of 46 QTL associated with the different studied phenotypes, designated as T2DSL and its number, for Type 2 Diabetes Specific Locus and its number, were identified during our study, among which 19 QTL were not previously mapped. The genomic interval of the remaining 27 QTL previously reported, were fine mapped in our study. The genomic positions of 40 of the mapped QTL overlapped (clustered) on 11 different peaks or close genomic positions, while the remaining 6 QTL were unique. Further, our study showed a complex pattern of haplotype effects of the founders, with the wild-derived strains (mainly PWK) playing a significant role in the increase of AUC values.
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Affiliation(s)
- Hanifa J Abu-Toamih-Atamni
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel-Aviv University, Ramat Aviv, 69978, Tel-Aviv, Israel
| | - Iqbal M Lone
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel-Aviv University, Ramat Aviv, 69978, Tel-Aviv, Israel
| | - Ilona Binenbaum
- Center of Systems Biology, Biomedical Research Foundation of the Academy of Athens, Soranou Ephessiou Str, 11527, Athens, Greece
- Division of Pediatric Hematology-Oncology, First Department of Pediatrics, National and Kapodistrian University of Athens, Athens, Greece
| | - Richard Mott
- Department of Genetics, University College of London, London, UK
| | | | - Aristotelis Chatziioannou
- Center of Systems Biology, Biomedical Research Foundation of the Academy of Athens, Soranou Ephessiou Str, 11527, Athens, Greece
- e-NIOS Applications PC, 196 Syggrou Ave., 17671, Kallithea, Greece
| | - Fuad A Iraqi
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel-Aviv University, Ramat Aviv, 69978, Tel-Aviv, Israel.
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Ran H, Li C, Zhang M, Zhong J, Wang H. Neglected PTM in Animal Adipogenesis: E3-mediated Ubiquitination. Gene 2023:147574. [PMID: 37336271 DOI: 10.1016/j.gene.2023.147574] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 06/11/2023] [Accepted: 06/14/2023] [Indexed: 06/21/2023]
Abstract
Ubiquitination is a widespread post-transcriptional modification (PTM) that occurs during protein degradation in eukaryotes and participates in almost all physiological and pathological processes, including animal adipogenesis. Ubiquitination is a cascade reaction regulated by the activating enzyme E1, conjugating enzyme E2, and ligase E3. Several recent studies have reported that E3 ligases play important regulatory roles in adipogenesis. However, as a key influencing factor for the recognition and connection between the substrate and ubiquitin during ubiquitination, its regulatory role in adipogenesis has not received adequate attention. In this review, we summarize the E3s' regulation and modification targets in animal adipogenesis, explain the regulatory mechanisms in lipogenic-related pathways, and further analyze the existing positive results to provide research directions of guiding significance for further studies on the regulatory mechanisms of E3s in animal adipogenesis.
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Affiliation(s)
- Hongbiao Ran
- Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization, Sichuan Province and Ministry of Education, Southwest Minzu University, Chengdu, Sichuan 610041, People's Republic of China
| | - Chunyan Li
- Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization, Sichuan Province and Ministry of Education, Southwest Minzu University, Chengdu, Sichuan 610041, People's Republic of China
| | - Ming Zhang
- Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization, Sichuan Province and Ministry of Education, Southwest Minzu University, Chengdu, Sichuan 610041, People's Republic of China
| | - Jincheng Zhong
- Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization, Sichuan Province and Ministry of Education, Southwest Minzu University, Chengdu, Sichuan 610041, People's Republic of China
| | - Hui Wang
- Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization, Sichuan Province and Ministry of Education, Southwest Minzu University, Chengdu, Sichuan 610041, People's Republic of China.
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Abstract
The molecular mechanisms of cellular insulin action have been the focus of much investigation since the discovery of the hormone 100 years ago. Insulin action is impaired in metabolic syndrome, a condition known as insulin resistance. The actions of the hormone are initiated by binding to its receptor on the surface of target cells. The receptor is an α2β2 heterodimer that binds to insulin with high affinity, resulting in the activation of its tyrosine kinase activity. Once activated, the receptor can phosphorylate a number of intracellular substrates that initiate discrete signaling pathways. The tyrosine phosphorylation of some substrates activates phosphatidylinositol-3-kinase (PI3K), which produces polyphosphoinositides that interact with protein kinases, leading to activation of the kinase Akt. Phosphorylation of Shc leads to activation of the Ras/MAP kinase pathway. Phosphorylation of SH2B2 and of Cbl initiates activation of G proteins such as TC10. Activation of Akt and other protein kinases produces phosphorylation of a variety of substrates, including transcription factors, GTPase-activating proteins, and other kinases that control key metabolic events. Among the cellular processes controlled by insulin are vesicle trafficking, activities of metabolic enzymes, transcriptional factors, and degradation of insulin itself. Together these complex processes are coordinated to ensure glucose homeostasis.
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Stöhr O, Tao R, Miao J, Copps KD, White MF. FoxO1 suppresses Fgf21 during hepatic insulin resistance to impair peripheral glucose utilization and acute cold tolerance. Cell Rep 2021; 34:108893. [PMID: 33761350 PMCID: PMC8529953 DOI: 10.1016/j.celrep.2021.108893] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/22/2020] [Accepted: 03/02/2021] [Indexed: 12/28/2022] Open
Abstract
Fgf21 (fibroblast growth factor 21) is a regulatory hepatokine that, in pharmacologic form, powerfully promotes weight loss and glucose homeostasis. Although "Fgf21 resistance" is inferred from higher plasma Fgf21 levels in insulin-resistant mice and humans, diminished Fgf21 function is understood primarily via Fgf21 knockout mice. By contrast, we show that modestly reduced Fgf21-owing to cell-autonomous suppression by hepatic FoxO1-contributes to dysregulated metabolism in LDKO mice (Irs1L/L⋅Irs2L/L⋅CreAlb), a model of severe hepatic insulin resistance caused by deletion of hepatic Irs1 (insulin receptor substrate 1) and Irs2. Knockout of hepatic Foxo1 in LDKO mice or direct restoration of Fgf21 by adenoviral infection restored glucose utilization by BAT (brown adipose tissue) and skeletal muscle, normalized thermogenic gene expression in LDKO BAT, and corrected acute cold intolerance of LDKO mice. These studies highlight the Fgf21-dependent plasticity and importance of BAT function to metabolic health during hepatic insulin resistance.
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Affiliation(s)
- Oliver Stöhr
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02215, USA
| | - Rongya Tao
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02215, USA
| | - Ji Miao
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02215, USA
| | - Kyle D Copps
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02215, USA
| | - Morris F White
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02215, USA.
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Peroxisome Proliferator-Activated Receptors and Caloric Restriction-Common Pathways Affecting Metabolism, Health, and Longevity. Cells 2020; 9:cells9071708. [PMID: 32708786 PMCID: PMC7407644 DOI: 10.3390/cells9071708] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 07/14/2020] [Accepted: 07/14/2020] [Indexed: 02/06/2023] Open
Abstract
Caloric restriction (CR) is a traditional but scientifically verified approach to promoting health and increasing lifespan. CR exerts its effects through multiple molecular pathways that trigger major metabolic adaptations. It influences key nutrient and energy-sensing pathways including mammalian target of rapamycin, Sirtuin 1, AMP-activated protein kinase, and insulin signaling, ultimately resulting in reductions in basic metabolic rate, inflammation, and oxidative stress, as well as increased autophagy and mitochondrial efficiency. CR shares multiple overlapping pathways with peroxisome proliferator-activated receptors (PPARs), particularly in energy metabolism and inflammation. Consequently, several lines of evidence suggest that PPARs might be indispensable for beneficial outcomes related to CR. In this review, we present the available evidence for the interconnection between CR and PPARs, highlighting their shared pathways and analyzing their interaction. We also discuss the possible contributions of PPARs to the effects of CR on whole organism outcomes.
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Chen K, Wan X, Zhao L, Zhao S, Peng L, Yang W, Yuan J, Zhu L, Mo Z. Cbl Proto-Oncogene B (CBLB) c.197A>T Mutation Induces Mild Metabolic Dysfunction in Partial Type I Multiple Symmetric Lipomatosis (MSL). Diabetes Metab Syndr Obes 2020; 13:3535-3549. [PMID: 33116705 PMCID: PMC7547790 DOI: 10.2147/dmso.s273780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 09/11/2020] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Multiple symmetric lipomatosis (MSL) is a rare disease showing chronic progression of multiple, symmetrical, and non-encapsulated subcutaneous lipoma. The cause of the disease remains unknown. PATIENTS AND METHODS This study reported and summarized 13 sporadic cases of Type I MSL patients in terms of histopathology and cellular and molecular biology and assessed the CBLB c.197A>T mutation in the IRS1-PI3K-Akt pathway. RESULTS The clinical data showed that these 13 Type I patients were all male with a mean age of 57.0 ± 6.6 years old and consumed alcohol heavily. The laboratory tests revealed that most of the patients had hyperuricemia, diabetes, hyperinsulinemia, or insulin resistance; however, their blood lipid levels were close to a normal range. The imaging data exhibited lipomas that only occurred subcutaneously but not viscerally, ie, Types Ia (15.4%), Ib (30.8%), and Ic (53.8%). The molecular analyses of adipocytes of isoprenaline stimulated human adipose tissue-derived mesenchymal stromal cells (hADSCs) isolated from the adipose tissue lipoma-like masses (ATLLM) demonstrated that these adipocytes did not express UCP-1. The Cbl proto-oncogene B (CBLB), an E3 ubiquitin-protein ligase, was associated with insulin resistance and obesity and was mutated (ie, CBLB c.197A>T) in four MSL patients after the whole genome and Sanger sequencing of the blood samples. Furthermore, the CBLB c.197A>T mutation induced hADSC resistance to insulin by inactivation of the IRS-1-PI3K-AKT pathway. CONCLUSION This study analyzed clinical, histopathological, and cellular and molecular biological characterizations of 13 Type I MSL patients and identified the CBLB c.197A>T heterozygous mutation that could be responsible for MSL metabolic dysfunction or even MSL development.
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Affiliation(s)
- Ke Chen
- Department of Endocrinology, The Third Xiangya Hospital of Central South University, Changsha, Hunan410013, People’s Republic of China
| | - Xinxing Wan
- Department of Endocrinology, The Third Xiangya Hospital of Central South University, Changsha, Hunan410013, People’s Republic of China
| | - Liling Zhao
- Department of Endocrinology, The Third Xiangya Hospital of Central South University, Changsha, Hunan410013, People’s Republic of China
| | - Shaoli Zhao
- Department of Endocrinology, The Third Xiangya Hospital of Central South University, Changsha, Hunan410013, People’s Republic of China
| | - Lin Peng
- Department of Nephrology, The First Hospital of Changsha, Changsha, Hunan410005, People’s Republic of China
| | - Wenjun Yang
- Department of Endocrinology, The Third Xiangya Hospital of Central South University, Changsha, Hunan410013, People’s Republic of China
| | - Jingjing Yuan
- Department of Endocrinology, The Third Xiangya Hospital of Central South University, Changsha, Hunan410013, People’s Republic of China
| | - Liyong Zhu
- Department of General Surgery, The Third Xiangya Hospital of Central South University, Changsha, Hunan410013, People’s Republic of China
| | - Zhaohui Mo
- Department of Endocrinology, The Third Xiangya Hospital of Central South University, Changsha, Hunan410013, People’s Republic of China
- Correspondence: Zhaohui Mo Tel/Fax +86 731 88618006 Email
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8
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The DCBLD receptor family: emerging signaling roles in development, homeostasis and disease. Biochem J 2019; 476:931-950. [PMID: 30902898 DOI: 10.1042/bcj20190022] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 02/20/2019] [Accepted: 03/04/2019] [Indexed: 02/08/2023]
Abstract
The discoidin, CUB, and LCCL domain-containing (DCBLD) receptor family are composed of the type-I transmembrane proteins DCBLD1 and DCBLD2 (also ESDN and CLCP1). These proteins are highly conserved across vertebrates and possess similar domain structure to that of neuropilins, which act as critical co-receptors in developmental processes. Although DCBLD1 remains largely uncharacterized, the functional and mechanistic roles of DCBLD2 are emerging. This review provides a comprehensive discussion of this presumed receptor family, ranging from structural and signaling aspects to their associations with cancer, physiology, and development.
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Ameen GI, Mora S. Cbl downregulation increases RBP4 expression in adipocytes of female mice. J Endocrinol 2018; 236:29-41. [PMID: 29114012 PMCID: PMC5744582 DOI: 10.1530/joe-17-0359] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2017] [Accepted: 11/07/2017] [Indexed: 11/30/2022]
Abstract
Obesity leads to adipose tissue dysfunction, insulin resistance and diabetes. Adipose tissue produces adipokines that contribute to regulate insulin sensitivity. In turn, insulin stimulates the production and release of some adipokines. Casitas-b-lymphoma proteins (c-Cbl, Cbl-b and Cbl3) are intracellular adaptor signalling proteins that are rapidly phosphorylated by activation of tyrosine kinase receptors. c-Cbl is rapidly phosphorylated by insulin in adipocytes. Here, we tested the hypothesis that Cbl signalling regulates adipokine expression in adipose tissue. We determined the adipokine profile of WAT of Cbl-/- and Cbl+/+ mice in the C57BL6 background. Female Cbl-/- mice exhibited altered expression of adiponectin, leptin and RBP4 in visceral adipose tissue, while no significant changes were seen in male mice. TNFα and IL6 levels were unaffected by Cbl depletion. RBP4 expression was unchanged in liver. Adipose tissue of Cbl-/- animals showed increased basal activation of extracellular regulated kinases (ERK1/2) compared to Cbl+/+. c-Cbl knockdown in 3T3L1 adipocytes also increased basal ERK phosphorylation and RBP4 expression. Inhibition of ERK1/2 phosphorylation in Cbl-depleted 3T3L1 adipocytes or in adipose tissue explants of Cbl-/- mice reduced RBP4 mRNA. 17β-Estradiol increased RBP4 mRNA in adipocytes. Cbl depletion did not change ER expression but increased phosphorylation of ERα at S118, a target site for ERK1/2. ERK1/2 inhibition reduced phosphoER and RBP4 levels. These findings suggest that Cbl contributes to regulate RBP4 expression in adipose of female mice through ERK1/2-mediated activation of ERα. Since Cbl signalling is compromised in diabetes, these data highlight a novel mechanism that upregulates RBP4 locally.
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Affiliation(s)
- Gulizar Issa Ameen
- Department of Cellular and Molecular PhysiologyInstitute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Silvia Mora
- Department of Cellular and Molecular PhysiologyInstitute of Translational Medicine, University of Liverpool, Liverpool, UK
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10
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Lima-Cabello E, Morales-Santana S, León J, Alché V, Clemente A, Alché JD, Jimenez-Lopez JC. Narrow-leafed lupin (Lupinus angustifoliusL.) seed β-conglutins reverse the induced insulin resistance in pancreatic cells. Food Funct 2018; 9:5176-5188. [DOI: 10.1039/c8fo01164h] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Narrow-leafed lupin β-conglutin proteins may help to prevent and treat insulin resistance through pleiotropic effects.
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Affiliation(s)
- Elena Lima-Cabello
- Department of Biochemistry
- Cell & Molecular Biology of Plants; Estacion Experimental del Zaidín
- Spanish National Research Council (CSIC)
- Granada E-18008
- Spain
| | - Sonia Morales-Santana
- CIBER of Fragility and Healthy Aging (CIBERFES)
- Endocrinology Unit
- Endocrinology Division
- Biomedical Research Institute of Granada – “IBS.Granada”
- University Hospital San Cecilio
| | - Josefa León
- Clinical Management Unit of Digestive System
- San Cecilio University Hospital
- Biomedical Research Institute of Granada – “IBS.Granada”
- University Hospital San Cecilio
- Granada E-18012
| | - Victor Alché
- Andalusian Health System
- Health Center “Villanueva de las Torres”
- Granada E-18539
- Spain
| | - Alfonso Clemente
- Department of Physiology and Biochemistry of Animal Nutrition; Estacion Experimental del Zaidin
- Spanish National Research Council (CSIC)
- Granada E-18100
- Spain
| | - Juan D. Alché
- Department of Biochemistry
- Cell & Molecular Biology of Plants; Estacion Experimental del Zaidín
- Spanish National Research Council (CSIC)
- Granada E-18008
- Spain
| | - Jose C. Jimenez-Lopez
- Department of Biochemistry
- Cell & Molecular Biology of Plants; Estacion Experimental del Zaidín
- Spanish National Research Council (CSIC)
- Granada E-18008
- Spain
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Schmid FM, Schou KB, Vilhelm MJ, Holm MS, Breslin L, Farinelli P, Larsen LA, Andersen JS, Pedersen LB, Christensen ST. IFT20 modulates ciliary PDGFRα signaling by regulating the stability of Cbl E3 ubiquitin ligases. J Cell Biol 2017; 217:151-161. [PMID: 29237719 PMCID: PMC5748969 DOI: 10.1083/jcb.201611050] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 01/20/2017] [Accepted: 08/24/2017] [Indexed: 12/28/2022] Open
Abstract
PDGFRα signals from cilia to control development and tumorigenesis. Schmid et al. now show that intraflagellar transport protein 20 (IFT20) interacts with and stabilizes the E3 ubiquitin ligases c-Cbl and Cbl-b to promote feedback inhibition of PDGFRα signaling at the primary cilium. Primary cilia have pivotal roles as organizers of many different signaling pathways, including platelet-derived growth factor receptor α (PDGFRα) signaling, which, when aberrantly regulated, is associated with developmental disorders, tumorigenesis, and cancer. PDGFRα is up-regulated during ciliogenesis, and ciliary localization of the receptor is required for its appropriate ligand-mediated activation by PDGF-AA. However, the mechanisms regulating sorting of PDGFRα and feedback inhibition of PDGFRα signaling at the cilium are unknown. Here, we provide evidence that intraflagellar transport protein 20 (IFT20) interacts with E3 ubiquitin ligases c-Cbl and Cbl-b and is required for Cbl-mediated ubiquitination and internalization of PDGFRα for feedback inhibition of receptor signaling. In wild-type cells treated with PDGF-AA, c-Cbl becomes enriched in the cilium, and the receptor is subsequently ubiquitinated and internalized. In contrast, in IFT20-depleted cells, PDGFRα localizes aberrantly to the plasma membrane and is overactivated after ligand stimulation because of destabilization and degradation of c-Cbl and Cbl-b.
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Affiliation(s)
- Fabian Marc Schmid
- Department of Biology, Section of Cell Biology and Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Kenneth Bødtker Schou
- Department of Biology, Section of Cell Biology and Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Martin Juel Vilhelm
- Department of Biology, Section of Cell Biology and Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Maria Schrøder Holm
- Department of Biology, Section of Cell Biology and Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Loretta Breslin
- Department of Biology, Section of Cell Biology and Physiology, University of Copenhagen, Copenhagen, Denmark.,Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Pietro Farinelli
- Department of Biology, Section of Cell Biology and Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Lars Allan Larsen
- Wilhelm Johannsen Centre for Functional Genome Research, Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | | | - Lotte Bang Pedersen
- Department of Biology, Section of Cell Biology and Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Søren Tvorup Christensen
- Department of Biology, Section of Cell Biology and Physiology, University of Copenhagen, Copenhagen, Denmark
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12
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Dahlman I, Belarbi Y, Laurencikiene J, Pettersson AM, Arner P, Kulyté A. Comprehensive functional screening of miRNAs involved in fat cell insulin sensitivity among women. Am J Physiol Endocrinol Metab 2017; 312:E482-E494. [PMID: 28270439 DOI: 10.1152/ajpendo.00251.2016] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 01/18/2017] [Accepted: 02/22/2017] [Indexed: 01/12/2023]
Abstract
The key pathological link between obesity and type 2 diabetes is insulin resistance, but the molecular mechanisms are not entirely identified. micro-RNAs (miRNA) are dysregulated in obesity and may contribute to insulin resistance. Our objective was to detect and functionally investigate miRNAs linked to insulin sensitivity in human subcutaneous white adipose tissue (scWAT). Subjects were selected based on the insulin-stimulated lipogenesis response of subcutaneous adipocytes. Global miRNA profiling was performed in abdominal scWAT of 18 obese insulin-resistance (OIR), 21 obese insulin-sensitive (OIS), and 9 lean women. miRNAs demonstrating differential expression between OIR and OIS women were overexpressed in human in vitro-differentiated adipocytes followed by assessment of lipogenesis and identification of miRNA targets by measuring mRNA/protein expression and 3'-untranslated region analysis. Eleven miRNAs displayed differential expression between OIR and OIS states. Overexpression of miR-143-3p and miR-652-3p increased insulin-stimulated lipogenesis in human in vitro differentiated adipocytes and directly or indirectly affected several genes/proteins involved in insulin signaling at transcriptional or posttranscriptional levels. Adipose expression of miR-143-3p and miR-652-3p was positively associated with insulin-stimulated lipogenesis in scWAT independent of body mass index. In conclusion, miR-143-3p and miR-652-3p are linked to scWAT insulin resistance independent of obesity and influence insulin-stimulated lipogenesis by interacting at different steps with insulin-signaling pathways.
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Affiliation(s)
- Ingrid Dahlman
- Lipid Laboratory, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, Sweden
| | - Yasmina Belarbi
- Lipid Laboratory, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, Sweden
| | - Jurga Laurencikiene
- Lipid Laboratory, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, Sweden
| | - Annie M Pettersson
- Lipid Laboratory, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, Sweden
| | - Peter Arner
- Lipid Laboratory, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, Sweden
| | - Agné Kulyté
- Lipid Laboratory, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, Sweden
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13
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Chen Z. Adapter proteins regulate insulin resistance and lipid metabolism in obesity. Sci Bull (Beijing) 2016. [DOI: 10.1007/s11434-016-1058-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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14
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Acupuncture Alters Expression of Insulin Signaling Related Molecules and Improves Insulin Resistance in OLETF Rats. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2016; 2016:9651592. [PMID: 27738449 PMCID: PMC5055976 DOI: 10.1155/2016/9651592] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 06/27/2016] [Indexed: 11/17/2022]
Abstract
To determine effect of acupuncture on insulin resistance in Otsuka Long-Evans Tokushima Fatty (OLETF) rats and to evaluate expression of insulin signaling components. Rats were divided into three groups: Sprague-Dawley (SD) rats, OLETF rats, and acupuncture+OLETF rats. Acupuncture was subcutaneously applied to Neiguan (PC6), Zusanli (ST36), and Sanyinjiao (SP6); in contrast, acupuncture to Shenshu (BL23) was administered perpendicularly. For Neiguan (PC6) and Zusanli (ST36), needles were connected to an electroacupuncture (EA) apparatus. Fasting blood glucose (FPG) was measured by glucose oxidase method. Plasma fasting insulin (FINS) and serum C peptide (C-P) were determined by ELISA. Protein and mRNA expressions of insulin signaling molecules were determined by Western blot and real-time RT-PCR, respectively. OLETF rats exhibit increased levels of FPG, FINS, C-P, and homeostasis model assessment-estimated insulin resistance (HOMA-IR), which were effectively decreased by acupuncture treatment. mRNA expressions of several insulin signaling related molecules IRS1, IRS2, Akt2, aPKCζ, and GLUT4 were decreased in OLETF rats compared to SD controls. Expression of these molecules was restored back to normal levels upon acupuncture administration. PI3K-p85α was increased in OLETF rats; this increase was also reversed by acupuncture treatment. Acupuncture improves insulin resistance in OLETF rats, possibly via regulating expression of key insulin signaling related molecules.
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15
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Voisinne G, García-Blesa A, Chaoui K, Fiore F, Bergot E, Girard L, Malissen M, Burlet-Schiltz O, Gonzalez de Peredo A, Malissen B, Roncagalli R. Co-recruitment analysis of the CBL and CBLB signalosomes in primary T cells identifies CD5 as a key regulator of TCR-induced ubiquitylation. Mol Syst Biol 2016; 12:876. [PMID: 27474268 PMCID: PMC4965873 DOI: 10.15252/msb.20166837] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
T-cell receptor (TCR) signaling is essential for the function of T cells and negatively regulated by the E3 ubiquitin-protein ligases CBL and CBLB Here, we combined mouse genetics and affinity purification coupled to quantitative mass spectrometry to monitor the dynamics of the CBL and CBLB signaling complexes that assemble in normal T cells over 600 seconds of TCR stimulation. We identify most previously known CBL and CBLB interacting partners, as well as a majority of proteins that have not yet been implicated in those signaling complexes. We exploit correlations in protein association with CBL and CBLB as a function of time of TCR stimulation for predicting the occurrence of direct physical association between them. By combining co-recruitment analysis with biochemical analysis, we demonstrated that the CD5 transmembrane receptor constitutes a key scaffold for CBL- and CBLB-mediated ubiquitylation following TCR engagement. Our results offer an integrated view of the CBL and CBLB signaling complexes induced by TCR stimulation and provide a molecular basis for their negative regulatory function in normal T cells.
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Affiliation(s)
- Guillaume Voisinne
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Inserm, CNRS, Marseille, France
| | - Antonio García-Blesa
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Inserm, CNRS, Marseille, France
| | - Karima Chaoui
- Institut de Pharmacologie et de Biologie Structurale, Département Biologie Structural Biophysique, Protéomique Génopole Toulouse Midi Pyrénées, CNRS UMR 5089, Toulouse Cedex, France
| | - Frédéric Fiore
- Centre d'Immunophénomique, Aix Marseille Université UM2, Inserm US012, CNRS UMS3367, Marseille, France
| | - Elise Bergot
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Inserm, CNRS, Marseille, France
| | - Laura Girard
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Inserm, CNRS, Marseille, France Centre d'Immunophénomique, Aix Marseille Université UM2, Inserm US012, CNRS UMS3367, Marseille, France
| | - Marie Malissen
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Inserm, CNRS, Marseille, France Centre d'Immunophénomique, Aix Marseille Université UM2, Inserm US012, CNRS UMS3367, Marseille, France
| | - Odile Burlet-Schiltz
- Institut de Pharmacologie et de Biologie Structurale, Département Biologie Structural Biophysique, Protéomique Génopole Toulouse Midi Pyrénées, CNRS UMR 5089, Toulouse Cedex, France
| | - Anne Gonzalez de Peredo
- Institut de Pharmacologie et de Biologie Structurale, Département Biologie Structural Biophysique, Protéomique Génopole Toulouse Midi Pyrénées, CNRS UMR 5089, Toulouse Cedex, France
| | - Bernard Malissen
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Inserm, CNRS, Marseille, France Centre d'Immunophénomique, Aix Marseille Université UM2, Inserm US012, CNRS UMS3367, Marseille, France
| | - Romain Roncagalli
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Inserm, CNRS, Marseille, France
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16
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Emdal KB, Pedersen AK, Bekker-Jensen DB, Tsafou KP, Horn H, Lindner S, Schulte JH, Eggert A, Jensen LJ, Francavilla C, Olsen JV. Temporal proteomics of NGF-TrkA signaling identifies an inhibitory role for the E3 ligase Cbl-b in neuroblastoma cell differentiation. Sci Signal 2015; 8:ra40. [PMID: 25921289 DOI: 10.1126/scisignal.2005769] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
SH-SY5Y neuroblastoma cells respond to nerve growth factor (NGF)-mediated activation of the tropomyosin-related kinase A (TrkA) with neurite outgrowth, thereby providing a model to study neuronal differentiation. We performed a time-resolved analysis of NGF-TrkA signaling in neuroblastoma cells using mass spectrometry-based quantitative proteomics. The combination of interactome, phosphoproteome, and proteome data provided temporal insights into the molecular events downstream of NGF binding to TrkA. We showed that upon NGF stimulation, TrkA recruits the E3 ubiquitin ligase Cbl-b, which then becomes phosphorylated and ubiquitylated and decreases in abundance. We also found that recruitment of Cbl-b promotes TrkA ubiquitylation and degradation. Furthermore, the amount of phosphorylation of the kinase ERK and neurite outgrowth increased upon Cbl-b depletion in several neuroblastoma cell lines. Our findings suggest that Cbl-b limits NGF-TrkA signaling to control the length of neurites.
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Affiliation(s)
- Kristina B Emdal
- Proteomics Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen, Denmark
| | - Anna-Kathrine Pedersen
- Proteomics Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen, Denmark
| | - Dorte B Bekker-Jensen
- Proteomics Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen, Denmark
| | - Kalliopi P Tsafou
- Disease Systems Biology Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Heiko Horn
- Disease Systems Biology Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Sven Lindner
- Department of Pediatric Oncology and Hematology, University Children's Hospital Essen, Hufelandstrasse 55, 45122 Essen, Germany
| | - Johannes H Schulte
- Department of Pediatric Oncology and Hematology, University Children's Hospital Essen, Hufelandstrasse 55, 45122 Essen, Germany. Department of Pediatric Oncology and Hematology, Charité Berlin, Charitéplatz 1, 10117 Berlin, Germany. German Cancer Consortium (DKTK), 13353 Berlin, Germany
| | - Angelika Eggert
- Department of Pediatric Oncology and Hematology, University Children's Hospital Essen, Hufelandstrasse 55, 45122 Essen, Germany. Department of Pediatric Oncology and Hematology, Charité Berlin, Charitéplatz 1, 10117 Berlin, Germany. German Cancer Consortium (DKTK), 13353 Berlin, Germany
| | - Lars J Jensen
- Disease Systems Biology Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Chiara Francavilla
- Proteomics Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen, Denmark.
| | - Jesper V Olsen
- Proteomics Program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen, Denmark.
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17
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Lutz-Nicoladoni C, Wolf D, Sopper S. Modulation of Immune Cell Functions by the E3 Ligase Cbl-b. Front Oncol 2015; 5:58. [PMID: 25815272 PMCID: PMC4356231 DOI: 10.3389/fonc.2015.00058] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 02/24/2015] [Indexed: 01/10/2023] Open
Abstract
Maintenance of immunological tolerance is a critical hallmark of the immune system. Several signaling checkpoints necessary to balance activating and inhibitory input to immune cells have been described so far, among which the E3 ligase Cbl-b appears to be a central player. Cbl-b is expressed in all leukocyte subsets and regulates several signaling pathways in T cells, NK cells, B cells, and different types of myeloid cells. In most cases, Cbl-b negatively regulates activation signals through antigen or pattern recognition receptors and co-stimulatory molecules. In line with this function, cblb-deficient immune cells display lower activation thresholds and cblb knockout mice spontaneously develop autoimmunity and are highly susceptible to experimental autoimmunity. Interestingly, genetic association studies link CBLB-polymorphisms with autoimmunity also in humans. Vice versa, the increased activation potential of cblb-deficient cells renders them more potent to fight against malignancies or infections. Accordingly, several reports have shown that cblb knockout mice reject tumors, which mainly depends on cytotoxic T and NK cells. Thus, targeting Cbl-b may be an interesting strategy to enhance anti-cancer immunity. In this review, we summarize the findings on the molecular function of Cbl-b in different cell types and illustrate the potential of Cbl-b as target for immunomodulatory therapies.
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Affiliation(s)
- Christina Lutz-Nicoladoni
- Department of Hematology and Oncology, Medical University Innsbruck , Innsbruck , Austria ; Tumor Immunology Laboratory, Tyrolean Cancer Research Institute , Innsbruck , Austria
| | - Dominik Wolf
- Medical Clinic III for Oncology, Haematology and Rheumatology, University Clinic Bonn (UKB) , Bonn , Germany
| | - Sieghart Sopper
- Department of Hematology and Oncology, Medical University Innsbruck , Innsbruck , Austria ; Tumor Immunology Laboratory, Tyrolean Cancer Research Institute , Innsbruck , Austria
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18
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Liu Q, Zhou H, Langdon WY, Zhang J. E3 ubiquitin ligase Cbl-b in innate and adaptive immunity. Cell Cycle 2014; 13:1875-84. [PMID: 24875217 DOI: 10.4161/cc.29213] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Casitas B-lineage lymphoma proto-oncogene-b (Cbl-b), a RING finger E3 ubiquitin-protein ligase, has been demonstrated to play a crucial role in establishing the threshold for T-cell activation and controlling peripheral T-cell tolerance via multiple mechanisms. Accumulating evidence suggests that Cbl-b also regulates innate immune responses and plays an important role in host defense to pathogens. Understanding the signaling pathways regulated by Cbl-b in innate and adaptive immune cells is therefore essential for efficient manipulation of Cbl-b in emerging immunotherapies for human disorders such as autoimmune diseases, allergic inflammation, infections, and cancer. In this article, we review the latest developments in the molecular structural basis of Cbl-b function, the regulation of Cbl-b expression, the signaling mechanisms of Cbl-b in immune cells, as well as the biological function of Cbl-b in physiological and pathological immune responses in animal models and human diseases.
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Affiliation(s)
- Qingjun Liu
- Laboratory of Immunohematology; Beijing Institute of Transfusion Medicine; Beijing, PR China; Department of Microbial Infection and Immunity; The Ohio State University; Columbus, OH USA
| | - Hong Zhou
- Laboratory of Immunohematology; Beijing Institute of Transfusion Medicine; Beijing, PR China
| | - Wallace Y Langdon
- School of Pathology and Laboratory Medicine; University of Western Australia; Crawley, Western Australia, Australia
| | - Jian Zhang
- Department of Microbial Infection and Immunity; The Ohio State University; Columbus, OH USA
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19
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Lee H, Tsygankov AY. Cbl-family proteins as regulators of cytoskeleton-dependent phenomena. J Cell Physiol 2013; 228:2285-93. [DOI: 10.1002/jcp.24412] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 05/29/2013] [Indexed: 12/21/2022]
Affiliation(s)
- Hojin Lee
- Department of Microbiology and Immunology; Sol Sherry Thrombosis Research Center and Fels Institute for Cancer Research; Temple University School of Medicine; Philadelphia Pennsylvania
| | - Alexander Y. Tsygankov
- Department of Microbiology and Immunology; Sol Sherry Thrombosis Research Center and Fels Institute for Cancer Research; Temple University School of Medicine; Philadelphia Pennsylvania
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20
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Löffler MG, Birkenfeld AL, Philbrick KM, Belman JP, Habtemichael EN, Booth CJ, Castorena CM, Choi CS, Jornayvaz FR, Gassaway BM, Lee HY, Cartee GD, Philbrick W, Shulman GI, Samuel VT, Bogan JS. Enhanced fasting glucose turnover in mice with disrupted action of TUG protein in skeletal muscle. J Biol Chem 2013; 288:20135-50. [PMID: 23744065 DOI: 10.1074/jbc.m113.458075] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Insulin stimulates glucose uptake in 3T3-L1 adipocytes in part by causing endoproteolytic cleavage of TUG (tether containing a ubiquitin regulatory X (UBX) domain for glucose transporter 4 (GLUT4)). Cleavage liberates intracellularly sequestered GLUT4 glucose transporters for translocation to the cell surface. To test the role of this regulation in muscle, we used mice with muscle-specific transgenic expression of a truncated TUG fragment, UBX-Cter. This fragment causes GLUT4 translocation in unstimulated 3T3-L1 adipocytes. We predicted that transgenic mice would have GLUT4 translocation in muscle during fasting. UBX-Cter expression caused depletion of PIST (PDZ domain protein interacting specifically with TC10), which transmits an insulin signal to TUG. Whereas insulin stimulated TUG proteolysis in control muscles, proteolysis was constitutive in transgenic muscles. Fasting transgenic mice had decreased plasma glucose and insulin concentrations compared with controls. Whole-body glucose turnover was increased during fasting but not during hyperinsulinemic clamp studies. In muscles with the greatest UBX-Cter expression, 2-deoxyglucose uptake during fasting was similar to that in control muscles during hyperinsulinemic clamp studies. Fasting transgenic mice had increased muscle glycogen, and GLUT4 targeting to T-tubule fractions was increased 5.7-fold. Whole-body oxygen consumption (VO2), carbon dioxide production (VCO2), and energy expenditure were increased by 12-13%. After 3 weeks on a high fat diet, the decreased fasting plasma glucose in transgenic mice compared with controls was more marked, and increased glucose turnover was not observed; the transgenic mice continued to have an increased metabolic rate. We conclude that insulin stimulates TUG proteolysis to translocate GLUT4 in muscle, that this pathway impacts systemic glucose homeostasis and energy metabolism, and that the effects of activating this pathway are maintained during high fat diet-induced insulin resistance in mice.
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Affiliation(s)
- Michael G Löffler
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06520-8020, USA
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21
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Nadeau S, An W, Palermo N, Feng D, Ahmad G, Dong L, Borgstahl GEO, Natarajan A, Naramura M, Band V, Band H. Oncogenic Signaling by Leukemia-Associated Mutant Cbl Proteins. ACTA ACUST UNITED AC 2013; Suppl 6. [PMID: 23997989 DOI: 10.4172/2161-1009.s6-001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Members of the Cbl protein family (Cbl, Cbl-b, and Cbl-c) are E3 ubiquitin ligases that have emerged as critical negative regulators of protein tyrosine kinase (PTK) signaling. This function reflects their ability to directly interact with activated PTKs and to target them as well as their associated signaling components for ubiquitination. Given the critical roles of PTK signaling in driving oncogenesis, recent studies in animal models and genetic analyses in human cancer have firmly established that Cbl proteins function as tumor suppressors. Missense mutations or small in-frame deletions within the regions of Cbl protein that are essential for its E3 activity have been identified in nearly 5% of leukemia patients with myelodysplastic/myeloproliferative disorders. Based on evidence from cell culture studies, in vivo models and clinical data, we discuss the potential signaling mechanisms of mutant Cbl-driven oncogenesis. Mechanistic insights into oncogenic Cbl mutants and associated animal models are likely to enhance our understanding of normal hematopoietic stem cell homeostasis and provide avenues for targeted therapy of mutant Cbl-driven cancers.
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Affiliation(s)
- Scott Nadeau
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 985950 Nebraska Medical Center Omaha, NE 68198-5950, USA ; Departments of Genetics, Cell Biology & Anatomy, University of Nebraska Medical Center, 985950 Nebraska Medical Center Omaha, NE 68198-5950, USA
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22
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Lee JO, Lee SK, Kim JH, Kim N, You GY, Moon JW, Kim SJ, Park SH, Kim HS. Metformin regulates glucose transporter 4 (GLUT4) translocation through AMP-activated protein kinase (AMPK)-mediated Cbl/CAP signaling in 3T3-L1 preadipocyte cells. J Biol Chem 2012; 287:44121-9. [PMID: 23135276 DOI: 10.1074/jbc.m112.361386] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Metformin is a leading oral anti-diabetes mellitus medication and is known to stimulate GLUT4 translocation. However, the mechanism by which metformin acts is still largely unknown. Here, we showed that short time treatment with metformin rapidly increased phosphorylation of Cbl in an AMP-activated protein kinase (AMPK)-dependent fashion in 3T3-L1 preadipocytes. Metformin also increased phosphorylation of Src in an AMPK-dependent manner. Src inhibition blocked metformin-mediated Cbl phosphorylation, suggesting that metformin stimulates AMPK-Src-Cbl axis pathway. In addition, long term treatment with metformin stimulated the expression of Cbl-associated protein (CAP) mRNA and protein. Long term treatment with metformin stimulated phosphorylation of c-Jun N-terminal kinase (JNK) and its downstream molecule c-Jun, which is a critical molecule for CAP transcription. Knockdown of AMPK and JNK blocked metformin-induced expression of CAP, implying that metformin stimulates AMPK-JNK-CAP axis pathway. Moreover, AMPK knockdown attenuated metformin-induced Cbl/CAP multicomplex formation, which is critical for GLUT4 translocation. A colorimetric absorbance assay demonstrated that metformin-induced translocation of GLUT4 was suppressed in CAP or Cbl knockdown cells. Furthermore, the promoter activity of CAP was increased by metformin in an AMPK/JNK-dependent fashion. In summary, these results demonstrate that metformin modulates GLUT4 translocation by regulating Cbl and CAP signals via AMPK.
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Affiliation(s)
- Jung Ok Lee
- Department of Anatomy, Korea University College of Medicine, Seoul 136-705, Korea
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23
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Neuronal Cbl controls biosynthesis of insulin-like peptides in Drosophila melanogaster. Mol Cell Biol 2012; 32:3610-23. [PMID: 22778134 DOI: 10.1128/mcb.00592-12] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Cbl family proteins function as both E3 ubiquitin ligases and adaptor proteins to regulate various cellular signaling events, including the insulin/insulin-like growth factor 1 (IGF1) and epidermal growth factor (EGF) pathways. These pathways play essential roles in growth, development, metabolism, and survival. Here we show that in Drosophila melanogaster, Drosophila Cbl (dCbl) regulates longevity and carbohydrate metabolism through downregulating the production of Drosophila insulin-like peptides (dILPs) in the brain. We found that dCbl was highly expressed in the brain and knockdown of the expression of dCbl specifically in neurons by RNA interference increased sensitivity to oxidative stress or starvation, decreased carbohydrate levels, and shortened life span. Insulin-producing neuron-specific knockdown of dCbl resulted in similar phenotypes. dCbl deficiency in either the brain or insulin-producing cells upregulated the expression of dilp genes, resulting in elevated activation of the dILP pathway, including phosphorylation of Drosophila Akt and Drosophila extracellular signal-regulated kinase (dERK). Genetic interaction analyses revealed that blocking Drosophila epidermal growth factor receptor (dEGFR)-dERK signaling in pan-neurons or insulin-producing cells by overexpressing a dominant-negative form of dEGFR abolished the effect of dCbl deficiency on the upregulation of dilp genes. Furthermore, knockdown of c-Cbl in INS-1 cells, a rat β-cell line, also increased insulin biosynthesis and glucose-stimulated secretion in an ERK-dependent manner. Collectively, these results suggest that neuronal dCbl regulates life span, stress responses, and metabolism by suppressing dILP production and the EGFR-ERK pathway mediates the dCbl action. Cbl suppression of insulin biosynthesis is evolutionarily conserved, raising the possibility that Cbl may similarly exert its physiological actions through regulating insulin production in β cells.
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24
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Gilliam LAA, Neufer PD. Transgenic mouse models resistant to diet-induced metabolic disease: is energy balance the key? J Pharmacol Exp Ther 2012; 342:631-6. [PMID: 22700428 DOI: 10.1124/jpet.112.192146] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The prevalence and economic burden of obesity and type 2 diabetes is a driving force for the discovery of molecular targets to improve insulin sensitivity and glycemic control. Here, we review several transgenic mouse models that identify promising targets, ranging from proteins involved in the insulin signaling pathway, alterations of genes affecting energy metabolism, and transcriptional metabolic regulators. Despite the diverse endpoints in each model, a common thread that emerges is the necessity for maintenance of energy balance, suggesting pharmacotherapy must target the development of drugs that decrease energy intake, accelerate energy expenditure in a well controlled manner, or augment natural compensatory responses to positive energy balance.
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Affiliation(s)
- Laura A A Gilliam
- Department of Physiology, East Carolina University, Greenville, NC, USA
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25
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Akimov V, Rigbolt KTG, Nielsen MM, Blagoev B. Characterization of ubiquitination dependent dynamics in growth factor receptor signaling by quantitative proteomics. MOLECULAR BIOSYSTEMS 2011; 7:3223-33. [PMID: 21956701 DOI: 10.1039/c1mb05185g] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Protein ubiquitination is a dynamic reversible post-translational modification that plays a key role in the regulation of numerous cellular processes including signal transduction, endocytosis, cell cycle control, DNA repair and gene transcription. The conjugation of the small protein ubiquitin or chains of ubiquitin molecules of various types and lengths to targeted proteins is known to alter proteins' lifespan, localization and function and to modulate protein interactions. Despite its central importance in various aspects of cellular life and function there are only a limited number of reports investigating ubiquitination on a proteomic scale, mainly due to the inherited complexity and heterogeneity of ubiquitination. We describe here a quantitative proteomics strategy based on the specificity of ubiquitin binding domains (UBDs) and Stable Isotope Labeling by Amino acids in Cell culture (SILAC) for selectively decoding ubiquitination-driven processes involved in the regulation of cellular signaling networks. We applied this approach to characterize the temporal dynamics of ubiquitination events accompanying epidermal growth factor receptor (EGFR) signal transduction. We used recombinant UBDs derived from endocytic adaptor proteins for specific enrichment of ubiquitinated complexes from the EGFR network and subsequent quantitative analyses by high accuracy mass spectrometry. We show that the strategy is suitable for profiling the dynamics of ubiquitination occurring on individual proteins as well as ubiquitination-dependent events in signaling pathways. In addition to a detailed seven time-point profile of EGFR ubiquitination over 30 minutes of ligand stimulation, our data determined prominent involvement of Lysine-63 ubiquitin branching in EGF signaling. Furthermore, we found two centrosomal proteins, PCM1 and Azi1, to form a multi-protein complex with the ubiquitin E3 ligases MIB1 and WWP2 downstream of the EGFR, thereby revealing possible ubiquitination cross-talk between EGF signaling and centrosomal-dependent rearrangements of the microtubules. This is a general strategy that can be utilized to study the dynamics of other cellular systems and post-translational modifications.
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Affiliation(s)
- Vyacheslav Akimov
- Center for Experimental BioInformatics, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
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26
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Abstract
Recent studies have demonstrated that a number of E3 ubiquitin ligases, including Cbl, Smurf1, Smurf2, HDM2, BCA2, SCF(beta-TRCP) and XRNF185, play important roles in cell adhesion and migration. Cbl negatively regulates cell adhesion via alpha integrin and Rap1 and inhibits actin polymerization by ubiquitinating mDab1 and WAVE2. Smurf1 regulates cell migration through ubiquitination of RhoA, talin head domain and hPEM2, while Smurf2 ubiquitinates Smurf1, TGFbeta type I receptor and RaplB to modulate cell migration and adhesion. HDM2 negatively regulates cell migration by targeting NFAT (a transcription factor) for ubiquitination and degradation, while SCF(beta-TRCP) ubiquitinates Snail (a transcriptional repressor of E-cadherin) to inhibit cell migration. TRIM32 promotes cell migration through ubiquitination of Abl interactor 2 (Abi2), a tumor suppressor. RNF5 and XRNF185 modulate cell migration by ubiquitinating paxillin. Thus, these E3 ubiquitin ligases regulate cell adhesion and (or) migration through ubiquitination of their specific substrates.
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Affiliation(s)
- Cai Huang
- Department of Cell and Developmental Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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27
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Suzuki M, Setsuie R, Wada K. Ubiquitin carboxyl-terminal hydrolase l3 promotes insulin signaling and adipogenesis. Endocrinology 2009; 150:5230-9. [PMID: 19837878 DOI: 10.1210/en.2009-0332] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Insulin is a potent adipogenic hormone that triggers the induction of a series of transcription factors and specific proteins governing the differentiation of preadipocytes into mature adipocytes. Here we report that ubiquitin carboxyl-terminal hydrolase (UCH)-L3, a deubiquitinating enzyme, promotes insulin signaling and adipogenesis. Uchl3(-/-) mice had less visceral white adipose tissue compared with wild-type mice. In vitro adipogenesis experiments revealed that mouse embryonic fibroblasts (MEFs) and preadipocytes from Uchl3(-/-) mice had impaired ability to differentiate into mature adipocytes than those from wild-type mice. This difference was diminished by removing insulin from the medium. RT-PCR analysis showed that insulin-regulated expression of srebp1c, fas, glut4, and adiponectin is impaired in Uchl3(-/-) cells. The phosphorylation of insulin/IGF-I receptor, Akt, glycogen synthase kinase-3beta, and FoxO1 was decreased in Uchl3(-/-) MEFs treated with insulin. Moreover, ectopic expression of wild-type UCH-L3 restored the phosphorylation of insulin/IGF-I receptor and adipocyte differentiation in Uchl3(-/-) MEFs. In contrast, hydrolase activity-deficient UCH-L3 did not enhance insulin signaling and the expression of glut4, fabp4, and adiponectin, resulting in impaired formation of large lipid droplets. These results suggest that UCH-L3 promotes adipogenesis by enhancing insulin signaling in a hydrolase activity-dependent manner.
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Affiliation(s)
- Mari Suzuki
- Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan
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28
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Saito M, Lessard SJ, Rivas DA, Reeder DW, Hawley JA, Yaspelkis BB. Activation of atypical protein kinase Czeta toward TC10 is regulated by high-fat diet and aerobic exercise in skeletal muscle. Metabolism 2008; 57:1173-80. [PMID: 18702941 PMCID: PMC2597576 DOI: 10.1016/j.metabol.2008.03.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2007] [Accepted: 03/04/2008] [Indexed: 12/29/2022]
Abstract
We determined whether sustained aerobic exercise reverses high-fat diet-induced impairments in the c-Cbl associated protein (CAP)/Casitas b-lineage lymphoma (c-Cbl) signaling cascade in rodent skeletal muscle. Sprague-Dawley rats were placed into either control (n = 16) or high-fat-fed (n = 32) diet groups for 4 weeks. During a subsequent 4-week experimental period, 16 high-fat-fed rats remained sedentary, 16 high-fat-fed rats completed 4 weeks of exercise training, and control animals were sedentary and remained on the control diet. After the intervention period, animals were subjected to hind limb perfusions in the presence (n = 8 per group) or absence (n = 8 per group) of insulin. In the plasma membrane fractions, neither high-fat feeding nor exercise training altered adaptor protein with PH and SH2 domains, (APS), c-Cbl, or TC10 protein concentrations. In contrast, CAP protein concentration and insulin-stimulated plasma membrane c-Cbl tyrosine phosphorylation were reduced by high-fat feeding; but exercise training reversed these impairments. Of note was that insulin-stimulated atypical protein kinase Czeta kinase activity toward TC10 was reduced by high-fat feeding but normalized by exercise training. We conclude that sustained (4 weeks) exercise training can reverse high-fat diet-induced impairments on the CAP/c-Cbl pathway in high-fat-fed rodent skeletal muscle. We also provide the first evidence that the CAP/c-Cbl insulin signaling cascade in skeletal muscle may directly interact with components of the classic (phosphoinositide 3-kinase dependent) insulin signaling cascade.
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Affiliation(s)
- Misato Saito
- Exercise Biochemistry Laboratory, Department of Kinesiology, California State University Northridge, CA 91330-8287, USA
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29
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Zhou ZR, Gao HC, Zhou CJ, Chang YG, Hong J, Song AX, Lin DH, Hu HY. Differential ubiquitin binding of the UBA domains from human c-Cbl and Cbl-b: NMR structural and biochemical insights. Protein Sci 2008; 17:1805-14. [PMID: 18596201 DOI: 10.1110/ps.036384.108] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The Cbl proteins, RING-type E3 ubiquitin ligases, are responsible for ubiquitinating the activated tyrosine kinases and targeting them for degradation. Both c-Cbl and Cbl-b have a UBA (ubiquitin-associated) domain at their C-terminal ends, and these two UBA domains share a high sequence similarity (75%). However, only the UBA from Cbl-b, but not from c-Cbl, can bind ubiquitin (Ub). To understand the mechanism by which the UBA domains specifically interact with Ub with different affinities, we determined the solution NMR structures of these two UBA domains, cUBA from human c-Cbl and UBAb from Cbl-b. Their structures show that these two UBA domains share the same fold, a compact three-helix bundle, highly resembling the typical UBA fold. Chemical shift perturbation experiments reveal that the helix-1 and loop-1 of UBAb form a predominately hydrophobic surface for Ub binding. By comparing the Ub-interacting surface on UBAb and its counterpart on cUBA, we find that the hydrophobic patch on cUBA is interrupted by a negatively charged residue Glu12. Fluorescence titration data show that the Ala12Glu mutant of UBAb completely loses the ability to bind Ub, whereas the mutation disrupting the dimerization has no significant effect on Ub binding. This study provides structural and biochemical insights into the Ub binding specificities of the Cbl UBA domains, in which the hydrophobic surface distribution on the first helix plays crucial roles in their differential affinities for Ub binding. That is, the amino acid residue diversity in the helix-1 region, but not the dimerization, determines the abilities of various UBA domains binding with Ub.
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Affiliation(s)
- Zi-Ren Zhou
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
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30
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Bernard JR, Saito M, Liao YH, Yaspelkis BB, Ivy JL. Exercise training increases components of the c-Cbl-associated protein/c-Cbl signaling cascade in muscle of obese Zucker rats. Metabolism 2008; 57:858-66. [PMID: 18502271 DOI: 10.1016/j.metabol.2008.01.035] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2007] [Accepted: 01/07/2008] [Indexed: 11/28/2022]
Abstract
The purpose of this investigation was to determine whether alterations in the c-Cbl-associated protein/c-Cbl pathway and/or p38-mitogen-activated protein kinase (p38 MAP kinase) were associated with improved skeletal muscle insulin responsiveness in exercise-trained obese Zucker rats. Obese Zucker rats ran 5 d/wk on a motorized treadmill for 90 minutes over a 7-week period. Age-matched obese Zucker rats (OB-SED) and their lean littermates (LN-SED) were obtained to serve as nontrained controls. Twenty-four (OB-EX-24 h) or 48 hours (OB-EX-48 h) after the last exercise bout, the trained rats were studied via the hind limb perfusion technique in the presence of insulin. Insulin-stimulated glucose uptake was significantly decreased across the skeletal muscle of OB-SED rats compared with LN-SED, but was normalized in the obese rats by 7 weeks of training. The insulin-stimulated plasma membrane protein concentrations of TC10 and glucose transporter 4 were reduced in the sedentary Zuckers, but both proteins were increased by the training protocol. Training did not increase insulin-stimulated p38 MAP kinase protein concentration, nor did it have an effect on insulin-stimulated p38 MAP kinase phosphorylation at the plasma membrane. These results suggest that skeletal muscle insulin resistance is associated with reduced expression of TC10 and that this deficiency can be corrected with exercise training.
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Affiliation(s)
- Jeffrey R Bernard
- Exercise Physiology and Metabolism Laboratory, Department of Kinesiology and Health Education, University of Texas at Austin, Austin, TX 78712, USA
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31
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Xu Y, Ikegami M, Wang Y, Matsuzaki Y, Whitsett JA. Gene expression and biological processes influenced by deletion of Stat3 in pulmonary type II epithelial cells. BMC Genomics 2007; 8:455. [PMID: 18070348 PMCID: PMC2234434 DOI: 10.1186/1471-2164-8-455] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2007] [Accepted: 12/10/2007] [Indexed: 11/10/2022] Open
Abstract
Background The signal transducer and activator of transcription 3 (STAT3) mediates gene expression in response to numerous growth factors and cytokines, playing an important role in many cellular processes. To better understand the molecular mechanisms by which Stat3 influences gene expression in the lung, the effect of pulmonary epithelial cell specific deletion of Stat3 on genome wide mRNA expression profiling was assessed. Differentially expressed genes were identified from Affymetrix Murine GeneChips analysis and subjected to gene ontology classification, promoter analysis, pathway mapping and literature mining. Results Total of 791 mRNAs were significantly increased and 314 mRNAs were decreased in response to the deletion of Stat3Δ/Δ in the lung. STAT is the most enriched cis-elements in the promoter regions of those differentially expressed genes. Deletion of Stat3 induced genes influencing protein metabolism, transport, chemotaxis and apoptosis and decreased the expression of genes mediating lipid synthesis and metabolism. Expression of Srebf1 and 2, genes encoding key regulators of fatty acid and steroid biosynthesis, was decreased in type II cells from the Stat3Δ/Δ mice, consistent with the observation that lung surfactant phospholipids content was decreased. Stat3 influenced both pro- and anti-apoptotic pathways that determine cell death or survival. Akt, a potential transcriptional target of Stat3, was identified as an important participant in Stat3 mediated pathways including Jak-Stat signaling, apoptosis, Mapk signaling, cholesterol and fatty acid biosynthesis. Conclusion Deletion of Stat3 from type II epithelial cells altered the expression of genes regulating diverse cellular processes, including cell growth, apoptosis and lipid metabolism. Pathway analysis indicates that STAT3 regulates cellular homeostasis through a complex regulatory network that likely enhances alveolar epithelial cell survival and surfactant/lipid synthesis, necessary for the protection of the lung during injury.
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Affiliation(s)
- Yan Xu
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Department of Pediatrics, University of Cincinnati College of Medicine, 3333 Burnet Avenue, Cincinnati, OH, USA.
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32
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Kozlov G, Peschard P, Zimmerman B, Lin T, Moldoveanu T, Mansur-Azzam N, Gehring K, Park M. Structural Basis for UBA-mediated Dimerization of c-Cbl Ubiquitin Ligase. J Biol Chem 2007; 282:27547-27555. [PMID: 17635922 DOI: 10.1074/jbc.m703333200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ligand-induced down-regulation by the ubiquitin-protein ligases, c-Cbl and Cbl-b, controls signaling downstream from many receptor-tyrosine kinases (RTK). Cbl proteins bind to phosphotyrosine residues on activated RTKs to affect ligand-dependent ubiquitylation of these receptors targeting them for degradation in the lysosome. Both c-Cbl and Cbl-b contain a ubiquitin-associated (UBA) domain, which is important for Cbl dimerization and tyrosine phosphorylation; however, the mechanism of UBA-mediated dimerization and its requirement for Cbl biological activity is unclear. Here, we report the crystal structure of the UBA domain of c-Cbl refined to 2.1-A resolution. The structure reveals the protein is a symmetric dimer tightly packed along a large hydrophobic surface formed by helices 2 and 3. NMR chemical shift mapping reveals heterodimerization can occur with the related Cbl-b UBA domain via the same surface employed for homodimerization. Disruption of c-Cbl dimerization by site-directed mutagenesis impairs c-Cbl phosphorylation following activation of the Met/hepatocyte growth factor RTK and c-Cbl-dependent ubiquitination of Met. This provides direct evidence for a role of Cbl dimerization in terminating signaling following activation of RTKs.
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Affiliation(s)
| | - Pascal Peschard
- Department of Biochemistry, McGill University; Molecular Oncology Group, McGill University Health Center, Montréal, Québec H3G 1Y6, Canada
| | | | - Tong Lin
- Molecular Oncology Group, McGill University Health Center, Montréal, Québec H3G 1Y6, Canada; Department of Medicine, McGill University
| | | | | | - Kalle Gehring
- Department of Biochemistry, McGill University; Molecular Oncology Group, McGill University Health Center, Montréal, Québec H3G 1Y6, Canada.
| | - Morag Park
- Department of Biochemistry, McGill University; Molecular Oncology Group, McGill University Health Center, Montréal, Québec H3G 1Y6, Canada; Department of Medicine, McGill University; Department of Oncology, McGill University.
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Peschard P, Kozlov G, Lin T, Mirza IA, Berghuis AM, Lipkowitz S, Park M, Gehring K. Structural basis for ubiquitin-mediated dimerization and activation of the ubiquitin protein ligase Cbl-b. Mol Cell 2007; 27:474-85. [PMID: 17679095 DOI: 10.1016/j.molcel.2007.06.023] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Revised: 05/02/2007] [Accepted: 06/20/2007] [Indexed: 11/18/2022]
Abstract
Cbl proteins are E3 ubiquitin ligases that are negative regulators of many receptor tyrosine kinases. Cbl-b and c-Cbl contain a ubiquitin-associated (UBA) domain, which is present in a variety of proteins involved in ubiquitin-mediated processes. Despite high sequence identity, Cbl UBA domains display remarkably different ubiquitin-binding properties. Here, we report the crystal structure of the UBA domain of Cbl-b in complex with ubiquitin at 1.9 A resolution. The structure reveals an atypical mechanism of ubiquitin recognition by the first helix of the UBA. Helices 2 and 3 of the UBA domain form a second binding surface, which mediates UBA dimerization in the crystal and in solution. Site-directed mutagenesis demonstrates that Cbl-b dimerization is regulated by ubiquitin binding and required for tyrosine phosphorylation of Cbl-b and ubiquitination of Cbl-b substrates. These studies demonstrate a role for ubiquitin in regulating biological activity by promoting protein dimerization.
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Affiliation(s)
- Pascal Peschard
- Department of Biochemistry, McGill University, Montréal, Canada
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34
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Limpert AS, Karlo JC, Landreth GE. Nerve growth factor stimulates the concentration of TrkA within lipid rafts and extracellular signal-regulated kinase activation through c-Cbl-associated protein. Mol Cell Biol 2007; 27:5686-98. [PMID: 17548467 PMCID: PMC1952120 DOI: 10.1128/mcb.01109-06] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Nerve growth factor (NGF) acts through its receptor, TrkA, to elicit the neuronal differentiation of PC12 cells through the action of extracellular signal-regulated kinase 1 (ERK1) and ERK2. Upon NGF binding, TrkA translocates and concentrates in cholesterol-rich membrane microdomains or lipid rafts, facilitating formation of receptor-associated signaling complexes, activation of downstream signaling pathways, and internalization into endosomes. We have investigated the mechanisms responsible for the localization of TrkA within lipid rafts and its ability to activate ERK1 and ERK2. We report that NGF treatment results in the translocation of activated forms of TrkA to lipid rafts, and this localization is important for efficient activation of the ERKs. TrkA is recruited and retained within lipid rafts through its association with flotillin, an intrinsic constituent of these membrane microdomains, via the adapter protein, c-Cbl associated protein (CAP). Mutant forms of CAP that lack protein interaction domains block TrkA localization to lipid rafts and attenuate ERK activation. Importantly, suppression of endogenous CAP expression inhibited NGF-stimulated neurite outgrowth from primary dorsal root ganglion neurons. These data provide a mechanism for the lipid raft localization of TrkA and establish the importance of the CAP adaptor protein for NGF activation of the ERKs and neuronal differentiation.
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Affiliation(s)
- Allison S Limpert
- Department of Neurosciences, Alzheimer Research Laboratory, Case Western Reserve University School of Medicine, Cleveland, OH 44106-4928, USA
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35
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Loeser S, Penninger JM. Regulation of peripheral T cell tolerance by the E3 ubiquitin ligase Cbl-b. Semin Immunol 2007; 19:206-14. [PMID: 17391982 DOI: 10.1016/j.smim.2007.02.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2007] [Accepted: 02/16/2007] [Indexed: 02/07/2023]
Abstract
The family of the Casitas B-lineage Lymphoma (Cbl) proteins, c-Cbl, Cbl-b, and Cbl-3, function as E3 ubiquitin ligases and molecular adaptors. In particular, Cbl-b acts as a gatekeeper in T cell activation that controls activation thresholds and the requirement for co-stimulation. Loss of Cbl-b expression renders animals susceptible to antigen-triggered autoimmunity suggesting that Cbl-b is a key autoimmunity gene. In addition, Cbl-b plays a critical role in T cell anergy and escape from regulatory T cells (Treg) suppression. Modulation of Cbl-b might provide us with a unique opportunity for future immune treatment of human disorders such as autoimmunity, immunodeficiency, or cancer.
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Affiliation(s)
- Stefanie Loeser
- IMBA, Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Dr. Bohrgasse 3, A-1030 Vienna, Austria.
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36
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Li M, Li Z, Morris DL, Rui L. Identification of SH2B2beta as an inhibitor for SH2B1- and SH2B2alpha-promoted Janus kinase-2 activation and insulin signaling. Endocrinology 2007; 148:1615-21. [PMID: 17204555 PMCID: PMC4710543 DOI: 10.1210/en.2006-1010] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The SH2B family has three members (SH2B1, SH2B2, and SH2B3) that contain conserved dimerization (DD), pleckstrin homology, and SH2 domains. The DD domain mediates the formation of homo- and heterodimers between members of the SH2B family. The SH2 domain of SH2B1 (previously named SH2-B) or SH2B2 (previously named APS) binds to phosphorylated tyrosines in a variety of tyrosine kinases, including Janus kinase-2 (JAK2) and the insulin receptor, thereby promoting the activation of JAK2 or the insulin receptor, respectively. JAK2 binds to various members of the cytokine receptor family, including receptors for GH and leptin, to mediate cytokine responses. In mice, SH2B1 regulates energy and glucose homeostasis by enhancing leptin and insulin sensitivity. In this work, we identify SH2B2beta as a new isoform of SH2B2 (designated as SH2B2alpha) derived from the SH2B2 gene by alternative mRNA splicing. SH2B2beta has a DD and pleckstrin homology domain but lacks a SH2 domain. SH2B2beta bound to both SH2B1 and SH2B2alpha, as demonstrated by both the interaction of glutathione S-transferase-SH2B2beta fusion protein with SH2B1 or SH2B2alpha in vitro and coimmunoprecipitation of SH2B2beta with SH2B1 or SH2B2alpha in intact cells. SH2B2beta markedly attenuated the ability of SH2B1 to promote JAK2 activation and subsequent tyrosine phosphorylation of insulin receptor substrate-1 by JAK2. SH2B2beta also significantly inhibited SH2B1- or SH2B2alpha-promoted insulin signaling, including insulin-stimulated tyrosine phosphorylation of insulin receptor substrate-1. These data suggest that SH2B2beta is an endogenous inhibitor of SH2B1 and/or SH2B2alpha, negatively regulating insulin signaling and/or JAK2-mediated cellular responses.
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Affiliation(s)
- Minghua Li
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan 48109-0622, USA
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37
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Lesniewski LA, Hosch SE, Neels JG, de Luca C, Pashmforoush M, Lumeng CN, Chiang SH, Scadeng M, Saltiel AR, Olefsky JM. Bone marrow-specific Cap gene deletion protects against high-fat diet-induced insulin resistance. Nat Med 2007; 13:455-62. [PMID: 17351624 DOI: 10.1038/nm1550] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2006] [Accepted: 01/18/2007] [Indexed: 02/06/2023]
Abstract
Cbl-associated protein (Cap) is a member of a phosphatidylinositol 3-kinase-independent pathway for insulin-stimulated translocation of the glucose transporter GLUT4. Despite this positive role of Cap in glucose uptake, here we show that deletion of the gene encoding Cap (official gene name: Sorbs1) protects against high-fat diet (HFD)-induced insulin resistance in mice while also having an opposite, insulin-sensitizing effect, accompanied by reduced tissue markers of inflammation. Given the emerging role of chronic inflammation in insulin resistance and the macrophage in initiating this inflammatory process, we considered that Sorbs1 deletion from macrophages may have resulted in the observed protection from HFD-induced insulin resistance. Using bone marrow transplantation to generate functional Sorbs1-null macrophages, we show that the insulin-sensitive phenotype can be transferred to wild-type mice by transplantation of Sorbs1-null bone marrow. These studies show that macrophages are an important cell type in the induction of insulin resistance and that Cap has a modulatory role in this function.
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Affiliation(s)
- Lisa A Lesniewski
- Department of Endocrinology and Metabolism, University of California at San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA
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Floyd ZE, Segura BM, He F, Stephens JM. Degradation of STAT5 proteins in 3T3-L1 adipocytes is induced by TNF-{alpha} and cycloheximide in a manner independent of STAT5A activation. Am J Physiol Endocrinol Metab 2007; 292:E461-8. [PMID: 16985255 DOI: 10.1152/ajpendo.00334.2006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Tumor necrosis factor-alpha (TNF-alpha) is a multifunctional cytokine that has been implicated as a causative factor in obesity-linked insulin resistance. It is commonly accepted that macrophage-derived TNF-alpha acts in a paracrine manner on adjacent adipocytes to inhibit the expression of various adipocyte genes and to attenuate insulin signaling. Several studies have revealed that signal transducer and activator of transcription (STAT)5 proteins are modulated during adipogenesis and can modulate the transcription of some adipocyte genes. In this study, we demonstrate that TNF-alpha treatment, in the presence of cycloheximide, also results in the rapid turnover of STAT5A and STAT5B in a process that is independent of STAT5 activation by tyrosine phosphorylation. In addition, STAT5B is more labile than STAT5A under these conditions, suggesting that the COOH terminus of STAT5 may be involved in the turnover of each protein. Initial characterization of the TNF-alpha and cycloheximide-mediated degradation of STAT5 indicates that inhibition of the proteasome stabilizes both forms of STAT5 in the presence of TNF-alpha. In addition, the use of an NF-kappaB inhibitor results in the stabilization of STAT5A in the presence of TNF-alpha and cycloheximide, indicating that the degradation of STAT5 proteins under these conditions may involve the NF-kappaB pathway. STAT5 proteins are abundantly expressed in mature adipocytes and are normally extremely stable proteins under a wide range of conditions. However, our results demonstrate that the potentiation of TNF-alpha-mediated signaling in the presence of cyclohexmide is associated with a significant increase in the degradation of STAT5 proteins in 3T3-L1 adipocytes.
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Affiliation(s)
- Z Elizabeth Floyd
- Department of Biological Sciences, Louisiana State University, 202 Life Sciences Bldg., Baton Rouge, LA 70803, USA
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Lodhi IJ, Chiang SH, Chang L, Vollenweider D, Watson RT, Inoue M, Pessin JE, Saltiel AR. Gapex-5, a Rab31 guanine nucleotide exchange factor that regulates Glut4 trafficking in adipocytes. Cell Metab 2007; 5:59-72. [PMID: 17189207 PMCID: PMC1779820 DOI: 10.1016/j.cmet.2006.12.006] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2006] [Revised: 10/27/2006] [Accepted: 12/11/2006] [Indexed: 10/23/2022]
Abstract
Insulin stimulates glucose uptake by promoting translocation of the Glut4 glucose transporter from intracellular storage compartments to the plasma membrane. In the absence of insulin, Glut4 is retained intracellularly; the mechanism underlying this process remains uncertain. Using the TC10-interacting protein CIP4 as bait in a yeast two-hybrid screen, we cloned a RasGAP and VPS9 domain-containing protein, Gapex-5/RME-6. The VPS9 domain is a guanine nucleotide exchange factor for Rab31, a Rab5 subfamily GTPase implicated in trans-Golgi network (TGN)-to-endosome trafficking. Overexpression of Rab31 blocks insulin-stimulated Glut4 translocation, whereas knockdown of Rab31 potentiates insulin-stimulated Glut4 translocation and glucose uptake. Gapex-5 is predominantly cytosolic in untreated cells; its overexpression promotes intracellular retention of Glut4 in adipocytes. Insulin recruits the CIP4/Gapex-5 complex to the plasma membrane, thus reducing Rab31 activity and permitting Glut4 vesicles to translocate to the cell surface, where Glut4 docks and fuses to transport glucose into the cell.
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Affiliation(s)
- Irfan J. Lodhi
- Life Sciences Institute
- Cellular and Molecular Biology Program University of Michigan Ann Arbor, MI 48109
| | | | | | - Daniel Vollenweider
- Department of Pharmacological Sciences Stony Brook University Stony Brook, NY 11794
| | - Robert T. Watson
- Department of Pharmacological Sciences Stony Brook University Stony Brook, NY 11794
| | | | - Jeffrey E. Pessin
- Department of Pharmacological Sciences Stony Brook University Stony Brook, NY 11794
| | - Alan R. Saltiel
- Life Sciences Institute
- Departments of Internal Medicine and Molecular and Integrative Physiology
- Cellular and Molecular Biology Program University of Michigan Ann Arbor, MI 48109
- *Corresponding author: Alan R. Saltiel Life Sciences Institute University of Michigan 210 Washtenaw Ave. Ann Arbor, MI 48109
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Abstract
Previous studies have suggested that activation of the Rho family member GTPase TC10 is necessary but not sufficient for the stimulation of glucose transport by insulin. We show here that endogenous TC10alpha is rapidly activated in response to insulin in 3T3L1 adipocytes in a phosphatidylinositol 3-kinase-independent manner, whereas platelet-derived growth factor was without effect. Knockdown of TC10alpha but not TC10beta by RNA interference inhibited insulin-stimulated glucose uptake as well as the translocation of the insulin-sensitive glucose transporter GLUT4 from intracellular sites to the plasma membrane. In contrast, loss of TC10alpha had no effect on the stimulation of Akt by insulin. Additionally, knockdown of TC10alpha inhibited insulin-stimulated translocation of its effector CIP4. These data indicate that TC10alpha is specifically required for insulin-stimulated glucose uptake in adipocytes.
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Affiliation(s)
- Louise Chang
- Life Sciences Institute, University of Michigan Medical Center, Ann Arbor, Michigan 48109-2216, USA
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41
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Schwenk RW, Eckel J. A novel method to monitor insulin-stimulated GTP-loading of Rab11a in cardiomyocytes. Cell Signal 2006; 19:825-30. [PMID: 17158030 DOI: 10.1016/j.cellsig.2006.10.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2006] [Revised: 10/12/2006] [Accepted: 10/15/2006] [Indexed: 11/21/2022]
Abstract
As a member of the Rab small GTPase family, Rab11a has been shown to be involved in different vesicle trafficking processes. In earlier work we identified Rab11a to be present in GLUT4-containing vesicles after insulin stimulation and showed its involvement in insulin-dependent glucose uptake. However, it remained elusive if Rab11a is directly activated by the insulin signalling cascade and at which step a potential activation occurs. To examine the GTP-loading of Rab11a, we introduced a biotinylated GTP-analog into H9c2-hIR cells, transiently overexpressing HA-tagged Rab11a, and measured its binding to the GTPase after insulin stimulation. We observed that Rab11a is transiently GTP-loaded after insulin stimulation with a 2.3 (+/-0.3) fold activation (n=5), reaching its maximum after 4 min and declining back to basal after additional 2 min. The activation of Rab11a is phosphatidylinositol 3-kinase (PI3-kinase) dependent and downstream of Akt, as shown by in vitro knockdown of this kinase. These data show that Rab11a is directly activated by insulin and represents an element of the GLUT4 trafficking machinery.
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Affiliation(s)
- Robert Wolfgang Schwenk
- Institute of Clinical Biochemistry and Pathobiochemistry, German Diabetes Center, Düsseldorf, Germany
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Molero JC, Turner N, Thien CBF, Langdon WY, James DE, Cooney GJ. Genetic ablation of the c-Cbl ubiquitin ligase domain results in increased energy expenditure and improved insulin action. Diabetes 2006; 55:3411-7. [PMID: 17130487 DOI: 10.2337/db06-0955] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Casitas b-lineage lymphoma (c-Cbl) is a multiadaptor protein with E3-ubiquitin ligase activity residing within its RING finger domain. We have previously reported that c-Cbl-deficient mice exhibit elevated energy expenditure, reduced adiposity, and improved insulin action. In this study, we examined mice expressing c-Cbl protein with a loss-of-function mutation within the RING finger domain (c-Cbl(A/-) mice). Compared with control animals, c-Cbl(A/-) mice display a phenotype that includes reduced adiposity, despite greater food intake; reduced circulating insulin, leptin, and triglyceride levels; and improved glucose tolerance. c-Cbl(A/-) mice also display elevated oxygen consumption (13%) and are protected against high-fat diet-induced obesity and insulin resistance. Unlike c-Cbl(A/-) mice, mice expressing a mutant c-Cbl with the phosphatidylinositol (PI) 3-kinase binding domain ablated (c-Cbl(F/F) mice) exhibited an insulin sensitivity, body composition, and energy expenditure similar to that of wild-type animals. These results indicate that c-Cbl ubiquitin ligase activity, but not c-Cbl-dependent activation of PI 3-kinase, plays a key role in the regulation of whole-body energy metabolism.
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Affiliation(s)
- Juan C Molero
- Garvan Institute of Medical Research, 384 Victoria St., Darlinghurst, NSW 2010, Australia
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43
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Swaminathan G, Tsygankov AY. The Cbl family proteins: ring leaders in regulation of cell signaling. J Cell Physiol 2006; 209:21-43. [PMID: 16741904 DOI: 10.1002/jcp.20694] [Citation(s) in RCA: 228] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The proto-oncogenic protein c-Cbl was discovered as the cellular form of v-Cbl, a retroviral transforming protein. This was followed over the years by important discoveries, which identified c-Cbl and other Cbl-family proteins as key players in several signaling pathways. c-Cbl has donned the role of a multivalent adaptor protein, capable of interacting with a plethora of proteins, and has been shown to positively influence certain biological processes. The identity of c-Cbl as an E3 ubiquitin ligase unveiled the existence of an important negative regulatory pathway involved in maintaining homeostasis in protein tyrosine kinase (PTK) signaling. Recent years have also seen the emergence of novel regulators of Cbl, which have provided further insights into the complexity of Cbl-influenced pathways. This review will endeavor to provide a summary of current studies focused on the effects of Cbl proteins on various biological processes and the mechanism of these effects. The major sections of the review are as follows: Structure and genomic organization of Cbl proteins; Phosphorylation of Cbl; Interactions of Cbl; Localization of Cbl; Mechanism of effects of Cbl: (a) Ubiquitylation-dependent events: This section elucidates the mechanism of Cbl-mediated downregulation of EGFR and details the PTK and non-PTKs targeted by Cbl. In addition, it addresses the functional requirements for E3 Ubiquitin ligase activity of Cbl and negative regulation of Cbl-mediated downregulation of PTKs, (b) Adaptor functions: This section discusses the mechanisms of adaptor functions of Cbl in mitogen-activated protein kinase (MAPK) activation, insulin signaling, regulation of Ras-related protein 1 (Rap1), PI-3' kinase signaling, and regulation of Rho-family GTPases and cytoskeleton; Biological functions: This section gives an account of the diverse biological functions of Cbl and includes the role of Cbl in transformation, T-cell signaling and thymus development, B-cell signaling, mast-cell degranulation, macrophage functions, bone development, neurite growth, platelet activation, muscle degeneration, and bacterial invasion; Conclusions and perspectives.
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Affiliation(s)
- Gayathri Swaminathan
- Department of Microbiology and Immunology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA
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Strawbridge AB, Elmendorf JS. Endothelin-1 impairs glucose transporter trafficking via a membrane-based mechanism. J Cell Biochem 2006; 97:849-56. [PMID: 16240321 PMCID: PMC2409058 DOI: 10.1002/jcb.20687] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Endothelin-1 (ET-1) disrupts insulin-regulated glucose transporter GLUT4 trafficking. Since the negative consequence of chronic ET-1 exposure appears to be independent of signal disturbance along the insulin receptor substrate-1/phosphatidylinositol (PI) 3-kinase (PI3K)/Akt-2 pathway of insulin action, we tested if ET-1 altered GLUT4 regulation engaged by osmotic shock, a PI3K-independent stimulus that mimics insulin action. Regulation of GLUT4 by hyperosmotic stress was impaired by ET-1. Because of the mutual disruption of both insulin- and hyperosmolarity-stimulated GLUT4 translocation, we tested whether shared signaling and/or key phosphatidylinositol 4,5-bisphosphate (PIP2)-regulated cytoskeletal events of GLUT4 trafficking were targets of ET-1. Both insulin and hyperosmotic stress signaling to Cbl were impaired by ET-1. Also, plasma membrane PIP2 and cortical actin levels were reduced in cells exposed to ET-1. Exogenous PIP2, but not PI 3,4,5-bisphosphate, restored actin structure, Cbl activation, and GLUT4 translocation. These data show that ET-1-induced PIP2/actin disruption impairs GLUT4 trafficking elicited by insulin and hyperosmolarity. In addition to showing for the first time the important role of PIP2-regulated cytoskeletal events in GLUT4 regulation by stimuli other than insulin, these studies reveal a novel function of PIP2/actin structure in signal transduction.
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Affiliation(s)
- Andrew B. Strawbridge
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Center for Diabetes Research, Indianapolis, Indiana
| | - Jeffrey S. Elmendorf
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Center for Diabetes Research, Indianapolis, Indiana
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Center for Diabetes Research, Indianapolis, Indiana
- *Correspondence to: Jeffrey S. Elmendorf, 635 Barnhill Drive, MS308A, Indianapolis, Indiana 46202., E-mail:
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45
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Ramm G, Larance M, Guilhaus M, James DE. A role for 14-3-3 in insulin-stimulated GLUT4 translocation through its interaction with the RabGAP AS160. J Biol Chem 2006; 281:29174-80. [PMID: 16880201 DOI: 10.1074/jbc.m603274200] [Citation(s) in RCA: 171] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Translocation of the insulin-regulated glucose transporter GLUT4 to the cell surface is dependent on the phosphatidylinositol 3-kinase/Akt pathway. The RabGAP (Rab GTPase-activating protein) AS160 (Akt substrate of 160 kDa) is a direct substrate of Akt and plays an essential role in the regulation of GLUT4 trafficking. We have used liquid chromatography tandem mass spectrometry to identify several 14-3-3 isoforms as AS160-interacting proteins. 14-3-3 proteins interact with AS160 in an insulin- and Akt-dependent manner via an Akt phosphorylation site, Thr-642. This correlates with the dominant negative effect of both the AS160(T642A) and the AS160(4P) mutants on insulin-stimulated GLUT4 translocation. Introduction of a constitutive 14-3-3 binding site into AS160(4P) restored 14-3-3 binding without disrupting AS160-IRAP (insulin-responsive amino peptidase) interaction and reversed the inhibitory effect of AS160(4P) on GLUT4 translocation. These data show that the insulin-dependent association of 14-3-3 with AS160 plays an important role in GLUT4 trafficking in adipocytes.
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Affiliation(s)
- Georg Ramm
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Sydney, NSW, Australia.
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Vinciguerra M, Foti M. PTEN and SHIP2 phosphoinositide phosphatases as negative regulators of insulin signalling. Arch Physiol Biochem 2006; 112:89-104. [PMID: 16931451 DOI: 10.1080/13813450600711359] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Insulin resistance in peripheral tissues is the primary cause responsible for onset of type II diabetes mellitus. Recently, the genetic and biochemical dissection of intracellular signalling pathways transducing the metabolic and mitogenic effects of insulin has contributed to the understanding of the molecular causes of this insulin resistance. In particular, important efforts have been developed to comprehend the role of negative regulators of insulin signalling, since they might represent future therapeutical targets to reduce insulin resistance in peripheral tissues. Herein, we will briefly review major intracellular signalling pathways activated by insulin and how they are negatively regulated by distinct mechanisms. In particular, the role of PTEN and SHIP2, two phosphoinositide phosphatases recently implicated as negative modulators of insulin signalling, is in focus. Current knowledge on the role of PTEN and SHIP2 in insulin resistance, type II diabetes and related disorders will also be discussed.
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Affiliation(s)
- Manlio Vinciguerra
- Department of Cellular Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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47
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Gupte A, Mora S. Activation of the Cbl insulin signaling pathway in cardiac muscle; Dysregulation in obesity and diabetes. Biochem Biophys Res Commun 2006; 342:751-7. [PMID: 16494846 DOI: 10.1016/j.bbrc.2006.02.023] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2006] [Accepted: 02/07/2006] [Indexed: 11/16/2022]
Abstract
In adipocytes, the Cbl/CAP dependent signaling pathway has been involved in regulating insulin-stimulated glucose uptake. We investigated activation of Cbl and its downstream effector TC10 in cardiac and skeletal muscle of Balb/C mice. Insulin administration resulted in Cbl phosphorylation in cardiac, skeletal muscle, and adipose tissue. Subsequent TC10 activation was detected only in heart and adipose tissue. c-Cbl and CAP gene expression was significantly reduced in the heart tissue of streptozotocin-induced diabetic animals, whereas no change was observed for other components of the pathway. No changes in Cbl expression were detected in hindlimb muscle. In leptin-/- obese mice Cbl expression in heart and adipose tissue was maintained, although insulin-mediated Cbl phosphorylation and subsequent TC10 activation were significantly reduced. In conclusion, our data demonstrate that Cbl/CAP/TC10 insulin signaling pathway is active in cardiac muscle and impaired during obesity and insulin deficiency.
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Affiliation(s)
- Anisha Gupte
- Division of Biology, Kansas State University, 232 Ackert Hall, Manhattan, KS 66506, USA
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48
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Inoue M, Chiang SH, Chang L, Chen XW, Saltiel AR. Compartmentalization of the exocyst complex in lipid rafts controls Glut4 vesicle tethering. Mol Biol Cell 2006; 17:2303-11. [PMID: 16525015 PMCID: PMC1446102 DOI: 10.1091/mbc.e06-01-0030] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Lipid raft microdomains act as organizing centers for signal transduction. We report here that the exocyst complex, consisting of Exo70, Sec6, and Sec8, regulates the compartmentalization of Glut4-containing vesicles at lipid raft domains in adipocytes. Exo70 is recruited by the G protein TC10 after activation by insulin and brings with it Sec6 and Sec8. Knockdowns of these proteins block insulin-stimulated glucose uptake. Moreover, their targeting to lipid rafts is required for glucose uptake and Glut4 docking at the plasma membrane. The assembly of this complex also requires the PDZ domain protein SAP97, a member of the MAGUKs family, which binds to Sec8 upon its translocation to the lipid raft. Exocyst assembly at lipid rafts sets up targeting sites for Glut4 vesicles, which transiently associate with these microdomains upon stimulation of cells with insulin. These results suggest that the TC10/exocyst complex/SAP97 axis plays an important role in the tethering of Glut4 vesicles to the plasma membrane in adipocytes.
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Affiliation(s)
- Mayumi Inoue
- Life Sciences Institute, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA
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49
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Bernard JR, Reeder DW, Herr HJ, Rivas DA, Yaspelkis BB. High-fat feeding effects on components of the CAP/Cbl signaling cascade in Sprague-Dawley rat skeletal muscle. Metabolism 2006; 55:203-12. [PMID: 16423627 DOI: 10.1016/j.metabol.2005.08.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2005] [Accepted: 08/21/2005] [Indexed: 10/25/2022]
Abstract
The aim of this investigation was to determine whether the CAP (Cbl-associated protein)/Cbl signaling cascade is present and responsive to insulin in skeletal muscle and if high-fat feeding impairs insulin-stimulated activation of this signaling cascade. Sprague-Dawley rats were assigned to either control (n = 16) or high fat-fed (n = 16) dietary groups. After a 12-week dietary period, animals were subjected to hind limb perfusions in the presence (n = 8 per group) or absence (n = 8 per group) of insulin. High-fat feeding reduced rates of insulin-stimulated skeletal muscle phosphatidylinositol 3-kinase activity and 3-O-methylglucose transport. In plasma membrane fractions, neither the high-fat diet nor insulin altered the insulin receptor beta subunit (IR-beta), APS (adaptor protein containing PH and SH2 domains), c-Cbl, or TC10 protein concentration, but high-fat feeding did decrease CAP protein concentration. APS, c-Cbl, CAP, and TC10 messenger RNA were present in the skeletal muscle and reflected the protein concentration of experimental groups. Despite insulin-stimulated plasma membrane IR-beta tyrosine phosphorylation being unaffected by high-fat feeding, c-Cbl tyrosine phosphorylation, the kinase activity of IR-beta toward APS, and glucose transporter 4 protein concentration were all significantly reduced in insulin-stimulated plasma membrane prepared from the skeletal muscle of high fat-fed animals. These findings suggest that the CAP/Cbl signaling cascade is present in skeletal muscle, activated by insulin, and impaired by high-fat feeding.
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Affiliation(s)
- Jeffrey R Bernard
- Department of Kinesiology, College of Health and Human Development, California State University Northridge, Northridge, CA 91330-8287, USA
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50
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Horne WC, Sanjay A, Bruzzaniti A, Baron R. The role(s) of Src kinase and Cbl proteins in the regulation of osteoclast differentiation and function. Immunol Rev 2006; 208:106-25. [PMID: 16313344 DOI: 10.1111/j.0105-2896.2005.00335.x] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The osteoclast resorbs mineralized bone during bone development, homeostasis, and repair. The deletion of the gene encoding the nonreceptor tyrosine kinase c-Src produces an osteopetrotic skeletal phenotype that is the consequence of the inability of the mature osteoclast to efficiently resorb bone. Src-/- osteoclasts exhibit reduced motility and abnormal organization of the apical secretory domain (the ruffled border) and attachment-related cytoskeletal elements that are necessary for bone resorption. A key function of Src in osteoclasts is to promote the rapid assembly and disassembly of the podosomes, the specialized integrin-based attachment structures of osteoclasts and other highly motile cells. Once recruited to the activated integrins, especially alphavbeta3), by the adhesion tyrosine kinase Pyk2, Src binds and phosphorylates Cbl and Cbl-b, homologous multisite adapter proteins with ubiquitin ligase activity. The Cbl proteins in turn recruit and activate additional signaling effectors, including phosphatidylinositol 3-kinase and dynamin, which play key roles in the development of cell polarity and the regulation of cell attachment and motility. In addition, Src and the Cbl proteins contribute to signaling cascades that are activated by several important receptors, including receptor activator of nuclear factor kappaB and the macrophage colony-stimulating factor receptor, and also downregulate the signaling from many of these receptors.
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Affiliation(s)
- William C Horne
- Department of Orthopaedics and Rehabilitation and Cell Biology, Yale University School of Medicine, New Haven, CT 06520-8044, USA
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