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Choi M, Lee J, Jeong K, Pak Y. Caveolin-2 palmitoylation turnover facilitates insulin receptor substrate-1-directed lipid metabolism by insulin receptor tyrosine kinase. Biochim Biophys Acta Mol Basis Dis 2024; 1870:167173. [PMID: 38631410 DOI: 10.1016/j.bbadis.2024.167173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 03/13/2024] [Accepted: 04/08/2024] [Indexed: 04/19/2024]
Abstract
Here, we show that insulin induces palmitoylation turnover of Caveolin-2 (Cav-2) in adipocytes. Acyl protein thioesterases-1 (APT1) catalyzes Cav-2 depalmitoylation, and zinc finger DHHC domain-containing protein palmitoyltransferase 21 (ZDHHC21) repalmitoylation of the depalmitoylated Cav-2 for the turnover, thereby controlling insulin receptor (IR)-Cav-2-insulin receptor substrate-1 (IRS-1)-Akt-driven signaling. Insulin-induced palmitoylation turnover of Cav-2 facilitated glucose uptake and fat storage through induction of lipogenic genes. Cav-2-, APT1-, and ZDHHC21-deficient adipocytes, however, showed increased induction of lipolytic genes and glycerol release. In addition, white adipose tissues from insulin sensitive and resistant obese patients exhibited augmented expression of LYPLA1 (APT1) and ZDHHC20 (ZDHHC20). Our study identifies the specific enzymes regulating Cav-2 palmitoylation turnover, and reveals a new mechanism by which insulin-mediated lipid metabolism is controlled in adipocytes.
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Affiliation(s)
- Moonjeong Choi
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Jaewoong Lee
- Department of Anatomy and Convergence Medical Science, College of Medicine, Institute of Medical Sciences, Gyeongsang National University, Jinju 52727, Republic of Korea
| | - Kyuho Jeong
- Department of Biochemistry, College of Medicine, Dongguk University, 123 Dongdae-ro, Gyeongju 38066, Republic of Korea
| | - Yunbae Pak
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 52828, Republic of Korea.
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Choi M, Kwon H, Pak Y. Caveolin-2 in association with nuclear lamina controls adipocyte hypertrophy. FASEB J 2023; 37:e22745. [PMID: 36637913 DOI: 10.1096/fj.202201028rr] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 12/13/2022] [Accepted: 12/19/2022] [Indexed: 01/14/2023]
Abstract
Here, we identify that Caveolin-2 (Cav-2), an integral membrane protein, controls adipocyte hypertrophy in association with nuclear lamina. In the hypertrophy stage of adipogenesis, pY19-Cav-2 association with lamin A/C facilitated the disengagement of CCAAT/enhancer-binding protein α (C/EBPα) and peroxisome proliferator-activated receptor γ (PPARγ) from lamin A/C and repressed Cav-2 promoter at the nuclear periphery for epigenetic activation of Cav-2, and thereby promoted C/EBPα and PPARγ-induced adipocyte hypertrophy. Stable expression of Cav-2 was required and retained by phosphorylation, deubiquitination, and association with lamin A/C for the adipocyte hypertrophy. However, obese adipocytes exhibited augmented Cav-2 stability resulting from the up-regulation of lamin A/C over lamin B1, protein tyrosine phosphatase 1B (PTP1B), and nuclear deubiquitinating enzyme (DUB), Uchl5. Our findings show a novel epigenetic regulatory mechanism of adipocyte hypertrophy by Cav-2 at the nuclear periphery.
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Affiliation(s)
- Moonjeong Choi
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju, South Korea
| | - Hayeong Kwon
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju, South Korea
| | - Yunbae Pak
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju, South Korea
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Choi M, Kwon H, Jeong K, Pak Y. Epigenetic regulation of Cebpb activation by pY19- Caveolin-2 at the nuclear periphery in association with the nuclear lamina. Biochim Biophys Acta Mol Cell Res 2022; 1869:119363. [PMID: 36165916 DOI: 10.1016/j.bbamcr.2022.119363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 08/22/2022] [Accepted: 09/11/2022] [Indexed: 06/16/2023]
Abstract
Here, we show that Caveolin-2 (Cav-2) is an epigenetic regulator for adipogenesis. Upon adipogenic stimulation, inner nuclear membrane (INM)-targeted pY19-Cav-2 interacted with lamin A/C to disengage the repressed Cebpb promoter from lamin A/C, which facilitated the Cebpb promoter association with lamin B1. Consequently, pY19-Cav-2 recruited lysine demethylase 4b (KDM4b) for demethylation of histone H3 lysine 9 trimethylation (H3K9me3) and histone acetyltransferase GCN5 for acetylation of H3K27, and subsequently RNA polymerase II (Pol II) on Cebpb promoter for epigenetic activation of Cebpb, to initiate adipogenesis. Cav-2 knock-down abrogated the Cebpb activation and blocked the Pparg2 and Cebpa activation. Re-expression of Cav-2 restored Cebpb activation and adipogenesis in Cav-2-deficient preadipocytes. Our data identify a new mechanism by which the epigenetic activation of Cebpb is controlled at the nuclear periphery to promote adipogenesis.
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Affiliation(s)
- Moonjeong Choi
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Hayeong Kwon
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Kyuho Jeong
- Department of Biochemistry, College of Medicine, Dongguk University, Gyeongju 38066, Republic of Korea
| | - Yunbae Pak
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 52828, Republic of Korea.
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Xu R, Shao Z, Cao Q. MicroRNA-144-3p enhances LPS induced septic acute lung injury in mice through downregulating Caveolin-2. Immunol Lett 2021; 231:18-25. [PMID: 33418009 DOI: 10.1016/j.imlet.2020.12.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 12/03/2020] [Accepted: 12/28/2020] [Indexed: 10/22/2022]
Abstract
OBJECTIVE The emphasis of this study focused on the possible implication and the mechanism of miR-144-3p in septic acute lung injury (ALI) condition. METHODS Mice were pre-injected with miR-144-3p agomir, miR-144-3p antagomir, sh-Caveolin-2 or PBS before 10 mg/kg LPS induced sepsis model establishment. The ratio of wet weight of lung tissues and body weight (W/W) was calculated. The pathological changes on lung tissues were observed by H&E staining. Secretions of inflammatory cytokines (TNF-α, IL-1β and IL-6) in both mouse serum and lung tissues were determined by ELISA. Cell apoptosis and cell morphology were measured by TUNEL staining and H&E staining. The expressions of miR-144-3p, Caveolin-2, apoptotic related proteins and JAK/STAT pathway related proteins were measured by qRT-PCR or/and Western blot. Dual luciferase reporter assay was applied to detect the binding of miR-144-3p with Caveolin-2. RESULTS LPS resulted in increased W/W, disrupted lung tissue, enhanced inflammatory response and cell apoptosis. miR-144-3p was upregulated while Caveolin-2 was downregulated in response to LPS treatment. Inflammation and cell apoptosis induced by LPS can be alleviated by miR-144-3p antagomir injection, but enhanced by miR-144-3p agomir or sh-Caveolin-2 treatment. miR-144-3p can negatively target Caveolin-2. miR-144-3p can activate the JAK/STAT signal pathway through Caveolin-2 in septic ALI mouse. CONCLUSION miR-144-3 can promote LPS induced septic ALI through downregulating Caveolin-2 to activate the JAK/STAT signal pathway.
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Affiliation(s)
- Ruiming Xu
- Emergency Department, Beijing Tongren Hospital (South District), Beijing 100176, PR China
| | - Zhengyi Shao
- Emergency Department, Beijing Tongren Hospital (South District), Beijing 100176, PR China
| | - Qiumei Cao
- Emergency Department, Beijing Tongren Hospital (South District), Beijing 100176, PR China.
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Kwon H, Choi M, Ahn Y, Pak Y. N-myristoylation regulates insulin-induced phosphorylation and ubiquitination of Caveolin-2 for insulin signaling. Biochem Biophys Res Commun 2020; 532:535-40. [PMID: 32896381 DOI: 10.1016/j.bbrc.2020.08.072] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 08/21/2020] [Indexed: 11/22/2022]
Abstract
N-myristoylation is a ubiquitous protein lipidation in eukaryotes, but regulatory roles for myristoylation on proteins still remain to be explored. Here, we show that N-myristoylation of Caveolin-2 (Cav-2) controls insulin signaling. Alternative translation initiation (ATI)-yielded truncated form of non-N-myristoylable Cav-2β and various conditional Cav-2 mutants were compared to full-length form of N-myristoylable Cav-2α. Insulin induced insulin receptor (IR) tyrosine kinase-catalyzed Tyr-19 phosphorylation of N-myristoylable M14A Cav-2 and triggered activation of IR signaling cascade. In contrast, insulin induced ubiquitination of non-N-myristoylable M1A and G2A Cav-2 to facilitate protein-tyrosine phosphatase 1B interaction with IR which desensitized IR signaling through internalization. Metabolic labeling and click chemistry showed palmitoylation of M14A but not M1A and G2A Cav-2. Insulin did not induce phosphorylation of M1A and G2A Cav-2 and Cav-2β. Like Cav-2α, G2A Cav-2 and Cav-2β formed large homo-oligomers localized in lipid rafts. These findings show Cav-2 N-myristoylation plays a crucial role to coordinate its phosphorylation, palmitoylation, and ubiquitination to control insulin signaling.
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Jiao F, Han T, Yuan C, Liang Y, Cui J, Zhuo M, Wang L. Caveolin-2 is regulated by BRD4 and contributes to cell growth in pancreatic cancer. Cancer Cell Int 2020; 20:55. [PMID: 32099528 PMCID: PMC7029443 DOI: 10.1186/s12935-020-1135-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 02/04/2020] [Indexed: 02/07/2023] Open
Abstract
Background The bromodomain and extra-terminal domain (BET) family of proteins, especially BRD4 play an important role in epigenetic regulation, and are essential for cell survival and also are promising anticancer targets. This study aims to analyze the effect of BRD4 on the cell growth and progression of pancreatic cancer and novel mechanisms involved. Methods Expression of BRD4 in pancreatic cancer and paired adjacent noncancerous tissues from 76 patients was analyzed by western blotting, immunohistochemistry, and real time PCR. Its correlation with the clinicopathological characteristics and prognosis of pancreatic cancer patients was analyzed. The effects of BRD4 on the cell proliferation were detected by colony formation assay and sulforhodamine B assay. Migration and invasion were determined by Transwell assays, and the effect of BRD4 on subcutaneous tumor formation was verified in nude mice. Cell cycle analysis was detected by flow cytometry. The potential downstream targets of BRD4 and related molecular mechanisms were clarified by RNA sequencing, chromatin immunoprecipitation and dual luciferase reporter assay. Results BRD4 was overexpressed in pancreatic cancer. Biological results showed that BRD4 functioned as tumor promoter, facilitated cell proliferation, migration and invasion in vitro and in vivo. Further, caveolin-2 was selected as the downstream gene of BRD4 by RNA sequencing. Caveolin-2 overexpression can partially reverse the decreased cell growth ability caused by BRD4 knockdown, but did not affect cell migration and invasion. Chromatin immunoprecipitation assay and dual luciferase reporter assay revealed BRD4 could bind to the promoter region of caveolin-2 and upregulate caveolin-2 expression. Clinical data further indicated a positive correlation between BRD4 and caveolin-2 expression. BRD4 (high)/caveolin-2 (high) correlated with shorter overall survival of patients with pancreatic cancer. Multivariate analysis revealed that both BRD4 and caveolin-2 were independent factors. Conclusions Our findings reveal the oncogenic effects of BRD4 in pancreatic cancer and elucidate a possible mechanism by which BRD4 and caveolin-2 act to enhance cell growth. Targeting the BRD4-caveolin-2 interaction by development of BET inhibitors will be a therapeutic strategy for pancreatic cancer.
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Affiliation(s)
- Feng Jiao
- 1Department of Oncology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, 160 Pujian Road, Shanghai, 200127 China
| | - Ting Han
- 1Department of Oncology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, 160 Pujian Road, Shanghai, 200127 China
| | - Cuncun Yuan
- 2Department of Pathology, Fudan University Eye Ear Nose and Throat Hospital, 83 Fenyang Road, Shanghai, 201114 China
| | - Yiyi Liang
- 1Department of Oncology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, 160 Pujian Road, Shanghai, 200127 China
| | - Jiujie Cui
- 1Department of Oncology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, 160 Pujian Road, Shanghai, 200127 China
| | - Meng Zhuo
- 1Department of Oncology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, 160 Pujian Road, Shanghai, 200127 China
| | - Liwei Wang
- 1Department of Oncology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, 160 Pujian Road, Shanghai, 200127 China
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Abstract
Background Caveolin-2 (CAV2) is reported to have an important role in cancer. The following study investigated the expression and function of CAV2 in kidney cancer in vitro and in vivo. Materials and methods Real-time PCR, immunohistochemistry and Western blotting analysis were used to determine CAV2, epidermal growth factor receptor (EGFR), phosphatidylinositol 3-kinase (PI3K) and protein kinase B (Akt) in kidney cancer cell line OS-RC-2 and clinical specimens. The role of CAV2 in maintaining kidney cancer malignant phenotype was examined by wound healing assay, Matrigel invasion assays and mouse orthotopic xenograft model. Results Higher expression of CAV2 was found in renal cell carcinoma tissue compared to normal tissue. Furthermore, increased expression of CAV2 was associated with cancer progression. Also, silencing of CAV2 inhibited the proliferation, migration and invasion, as well as the expression of EGFR, PI3K and p-Akt in OS-RC-2 cells in vitro, and OS-RC-2 xenograft growth in vivo. Conclusion Our results revealed that CAV2 promotes the growth of renal cell carcinoma through EGFR/PI3K/Akt pathway.
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Affiliation(s)
- Fu Liu
- The First People's Hospital of Ziyang, Sichuan, People's Republic of China,
| | - Zhi Shangli
- The First People's Hospital of Ziyang, Sichuan, People's Republic of China,
| | - Zhili Hu
- The Second Hospital Affiliated to Chongqing Medical University, Chongqing, People's Republic of China
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Kwon H, Jang D, Choi M, Lee J, Jeong K, Pak Y. Alternative translation initiation of Caveolin-2 desensitizes insulin signaling through dephosphorylation of insulin receptor by PTP1B and causes insulin resistance. Biochim Biophys Acta Mol Basis Dis 2018; 1864:2169-2182. [PMID: 29604334 DOI: 10.1016/j.bbadis.2018.03.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 03/08/2018] [Accepted: 03/26/2018] [Indexed: 12/30/2022]
Abstract
Insulin resistance, defined as attenuated sensitivity responding to insulin, impairs insulin action. Direct causes and molecular mechanisms of insulin resistance have thus far remained elusive. Here we show that alternative translation initiation (ATI) of Caveolin-2 (Cav-2) regulates insulin sensitivity. Cav-2β isoform yielded by ATI desensitizes insulin receptor (IR) via dephosphorylation by protein-tyrosine phosphatase 1B (PTP1B), and subsequent endocytosis and lysosomal degradation of IR, causing insulin resistance. Blockage of Cav-2 ATI protects against insulin resistance by preventing Cav-2β-PTP1B-directed IR desensitization, thereby normalizing insulin sensitivity and glucose uptake. Our findings show that Cav-2β is a negative regulator of IR signaling, and identify a mechanism causing insulin resistance through control of insulin sensitivity via Cav-2 ATI.
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Affiliation(s)
- Hayeong Kwon
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Donghwan Jang
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Moonjeong Choi
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Jaewoong Lee
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Kyuho Jeong
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Yunbae Pak
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 52828, Republic of Korea.
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Li J, Ruffenach G, Kararigas G, Cunningham CM, Motayagheni N, Barakai N, Umar S, Regitz-Zagrosek V, Eghbali M. Intralipid protects the heart in late pregnancy against ischemia/reperfusion injury via Caveolin2/STAT3/GSK-3β pathway. J Mol Cell Cardiol 2016; 102:108-116. [PMID: 27847332 DOI: 10.1016/j.yjmcc.2016.11.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 11/08/2016] [Accepted: 11/11/2016] [Indexed: 12/12/2022]
Abstract
BACKGROUND We recently demonstrated that the heart of late pregnant (LP) rodents is more prone to ischemia/reperfusion (I/R) injury compared to non-pregnant rodents. Lipids, particularly polyunsaturated fatty acids, have received special attention in the field of cardiovascular research. Here, we explored whether Intralipid (ITLD) protects the heart against I/R injury in LP rodents and investigated the mechanisms underlying this protection. METHODS AND RESULTS In-vivo female LP rat hearts or ex-vivo isolated Langendorff-perfused LP mouse hearts were subjected to ischemia followed by reperfusion with PBS or ITLD (one bolus of 5mg/kg of 20% in in-vivo and 1% in ex-vivo). Myocardial infarct size, mitochondrial calcium retention capacity, genome-wide expression profiling, pharmacological inhibition and co-immunoprecipitation were performed. One bolus of ITLD at reperfusion significantly reduced the in-vivo myocardial infarct size in LP rats (23.3±2% vs. 55.5±3.4% in CTRL, p<0.01). Postischemic administration of ITLD also protected the LP hearts against I/R injury ex-vivo. ITLD significantly increased the threshold for the opening of the mitochondrial permeability transition pore in response to calcium overload (nmol-calcium/mg-mitochondrial protein: 290±17 vs. 167±10 in CTRL, p<0.01) and significantly increased phosphorylation of STAT3 (1.8±0.08 vs. 1±0.16 in CTRL, p<0.05) and GSK-3β (2.63±0.55 vs. 1±0.0.34 in CTRL, p<0.05). The ITLD-induced cardioprotection was fully abolished by Stattic, a specific inhibitor of STAT3. Transcriptome analysis revealed caveolin 2 (Cav2) was significantly upregulated by ITLD in hearts of LP rats under I/R injury. Co-immunoprecipitation experiments showed that Cav2 interacts with STAT3. CONCLUSIONS ITLD protects the heart in late pregnancy against I/R injury by inhibiting the mPTP opening through Cav2/STAT3/GSK-3β pathway.
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Affiliation(s)
- Jingyuan Li
- Department of Anesthesiology, Division of Molecular Medicine, Cardiovascular Research Laboratory, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-1778, United States
| | - Gregoire Ruffenach
- Department of Anesthesiology, Division of Molecular Medicine, Cardiovascular Research Laboratory, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-1778, United States
| | - Georgios Kararigas
- Institute of Gender in Medicine, Center for Cardiovascular Research, Charite University Hospital, Germany; DZHK (German Centre for Cardiovascular Research), Berlin Partner Site, Germany
| | - Christine M Cunningham
- Department of Anesthesiology, Division of Molecular Medicine, Cardiovascular Research Laboratory, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-1778, United States
| | - Negar Motayagheni
- Department of Anesthesiology, Division of Molecular Medicine, Cardiovascular Research Laboratory, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-1778, United States
| | - Neusha Barakai
- Department of Anesthesiology, Division of Molecular Medicine, Cardiovascular Research Laboratory, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-1778, United States
| | - Soban Umar
- Department of Anesthesiology, Division of Molecular Medicine, Cardiovascular Research Laboratory, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-1778, United States
| | - Vera Regitz-Zagrosek
- Institute of Gender in Medicine, Center for Cardiovascular Research, Charite University Hospital, Germany; DZHK (German Centre for Cardiovascular Research), Berlin Partner Site, Germany
| | - Mansoureh Eghbali
- Department of Anesthesiology, Division of Molecular Medicine, Cardiovascular Research Laboratory, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-1778, United States.
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Kwon H, Lee J, Jeong K, Jang D, Choi M, Pak Y. A-type lamin-dependent homo-oligomerization for pY19- Caveolin-2 to function as an insulin-response epigenetic regulator. Biochim Biophys Acta 2016; 1863:2681-2689. [PMID: 27552914 DOI: 10.1016/j.bbamcr.2016.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 08/08/2016] [Accepted: 08/19/2016] [Indexed: 10/21/2022]
Abstract
Association of Caveolin-2 in the inner nuclear membrane specifically with A-type lamin is crucial for the maintenance of its Tyr-19 phosphorylation to promote insulin-response epigenetic activation at the nuclear periphery. Here, we identify that pY19-Caveolin-2 in the inner nuclear membrane exists as homo-oligomeric forms and the A-type lamin is required for sustenance of its oligomeric status. Oligomerization-defective and hence pY19-dephosphorylated monomeric Caveolin-2 in the inner nuclear membrane is unable to carry out Caveolin-2-mediated epigenetic activation of Egr-1 and JunB genes and transactivation of Elk-1 and STAT3 in response to insulin. The homo-oligomeric pY19-Caveolin-2 localizes in and recruits epigenetic modifiers to the A-type lamin-enriched inner nuclear membrane microdomain for the epigenetic activation. Our data show that A-type lamin-dependent Caveolin-2 homo-oligomerization in the inner nuclear membrane microdomain is a precondition for pY19-Caveolin-2-mediated insulin-response epigenetic activation at the nuclear periphery.
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Affiliation(s)
- Hayeong Kwon
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 660-701, Republic of Korea
| | - Jaewoong Lee
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 660-701, Republic of Korea
| | - Kyuho Jeong
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 660-701, Republic of Korea
| | - Donghwan Jang
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 660-701, Republic of Korea
| | - Moonjeong Choi
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 660-701, Republic of Korea
| | - Yunbae Pak
- Division of Life Science, Graduate School of Applied Life Science (BK21 Plus Program), PMBBRC, Gyeongsang National University, Jinju 660-701, Republic of Korea.
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Kwon H, Lee J, Jeong K, Jang D, Pak Y. Fatty acylated caveolin-2 is a substrate of insulin receptor tyrosine kinase for insulin receptor substrate-1-directed signaling activation. Biochim Biophys Acta 2015; 1853:1022-34. [PMID: 25667086 DOI: 10.1016/j.bbamcr.2015.02.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 01/30/2015] [Accepted: 02/01/2015] [Indexed: 12/30/2022]
Abstract
Here, we demonstrate that insulin receptor (IR) tyrosine kinase catalyzes Tyr-19 and Tyr-27 phosphorylation of caveolin-2 (cav-2), leading to stimulation of signaling proteins downstream of IR, and that the catalysis is dependent on fatty acylation status of cav-2, promoting its interaction with IR. Cav-2 is myristoylated at Gly-2 and palmitoylated at Cys-109, Cys-122, and Cys-145. The fatty acylation deficient mutants are unable to localize in the plasma membrane and not phosphorylated by IR tyrosine kinase. IR interacts with the C-terminal domain of cav-2 containing the cysteines for palmitoylation. IR mutants, Y999F and K1057A, but not W1220S, fail interaction with cav-2. Insulin receptor substrate-1 (IRS-1) is recruited to interact with the IR-catalyzed phospho-tyrosine cav-2, which facilitates IRS-1 association with and activation by IR to initiate IRS-1-mediated downstream signaling. Cav-2 fatty acylation and tyrosine phosphorylation are necessary for the IRS-1-dependent PI3K-Akt and ERK activations responsible for glucose uptake and cell survival and proliferation. In conclusion, fatty acylated cav-2 is a new substrate of IR tyrosine kinase, and the fatty acylation and phosphorylation of cav-2 present novel mechanisms by which insulin signaling is activated.
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Kwon H, Lee J, Jeong K, Jang D, Pak Y. A novel actin cytoskeleton-dependent noncaveolar microdomain composed of homo-oligomeric caveolin-2 for activation of insulin signaling. Biochim Biophys Acta 2013; 1833:2176-89. [PMID: 23665048 DOI: 10.1016/j.bbamcr.2013.05.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 05/01/2013] [Accepted: 05/03/2013] [Indexed: 12/22/2022]
Abstract
The role of caveolin-2 (cav-2), independently of caveolin-1 (cav-1) and caveolae, has remained elusive. Our data show that cav-2 exists in the plasma membrane (PM) in cells lacking cav-1 and forms homo-oligomeric complexes. Cav-2 did not interact with cavin-1 and cavin-2 in the PM. Rab6-GTP was required for the microtubule-dependent exocytic transport of cav-2 from the Golgi to the PM independently of cav-1. The cav-2-oligomerized noncaveolar microdomain was unaffected by cholesterol depletion and protected from shearing of silica-coated PM. Activation of insulin receptor (IR) was processed in the microdomain. Actin depolymerization affected the formation and sustenance of cav-2-oligomerized noncaveolar microdomain and attenuated IR recruitment to the microdomain thereby inhibiting IR signaling activation. Cav-2 shRNA stable cells and the cells ectopically expressing an oligomerization domain truncation mutant, cav-2∆47-86 exhibited retardation of IR signaling activation via the noncaveolar microdomain. Elevation in status of cav-2 expression rendered the noncaveolar activation of IR signaling in cav-1 down-regulated or/and cholesterol-depleted cells. Our findings reveal a novel homo-oligomeric cav-2 microdomain responsible for regulating activation of IR signaling in the PM.
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Affiliation(s)
- Hayeong Kwon
- Department of Biochemistry, Gyeongsang National University, Jinju, Republic of Korea
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Abstract
Caveolae are cholesterol- and glycosphingolipid-rich omega-shaped invaginations of the plasma membrane that are very abundant in vascular endothelial cells and present in most cell types. Caveolins are the major coat protein components of caveolae. Multiple studies using knockout mouse, small interfering RNA, and cell-permeable peptide delivery approaches have significantly enhanced our understanding of the role of endothelial caveolae and caveolin-1 in physiology and disease. Several postnatal pulmonary and cardiovascular pathologies have been reported in caveolin-1 knockout mice, many of which have been recently rescued by selective re-expression of caveolin-1 in endothelium of these mice. A large body of experimental evidence mostly using caveolin-1 knockout mice suggests that, depending on the disease model, endothelial caveolin-1 may play either a protective or a detrimental role. For instance, physiological or higher expression levels of caveolin-1 in endothelium might be beneficial in such diseases as pulmonary hypertension, cardiac hypertrophy, or ischemic injury. On the other hand, endothelial caveolin-1 might contribute to acute lung injury and inflammation, atherosclerosis or pathological angiogenesis associated with inflammatory bowel disease. Moreover, depending on the specific model, endothelial caveolin-1 may either promote or suppress tumor-induced angiogenesis. In addition to overwhelming evidence for the role of endothelial caveolin-1, more recent studies also suggest that endothelial caveolin-2 could possibly play a role in pulmonary disease. The purpose of this review is to focus on how caveolin-1 expressed in endothelial cells regulates endothelial cell signaling and function. The review places particular emphasis on relevance to disease, including but not limited to Pulmonary and cardiovascular disorders as well as cancer. In addition to caveolin-1, possible importance of the less-studied endothelial caveolin-2 in pulmonary diseases will be also discussed.
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Affiliation(s)
- Grzegorz Sowa
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, 65212, USA
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