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Gao XK, Sheng ZK, Lu YH, Sun YT, Rao XS, Shi LJ, Cong XX, Chen X, Wu HB, Huang M, Zheng Q, Guo JS, Jiang LJ, Zheng LL, Zhou YT. VAPB-mediated ER-targeting stabilizes IRS-1 signalosomes to regulate insulin/IGF signaling. Cell Discov 2023; 9:83. [PMID: 37528084 PMCID: PMC10394085 DOI: 10.1038/s41421-023-00576-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 06/08/2023] [Indexed: 08/03/2023] Open
Abstract
The scaffold protein IRS-1 is an essential node in insulin/IGF signaling. It has long been recognized that the stability of IRS-1 is dependent on its endomembrane targeting. However, how IRS-1 targets the intracellular membrane, and what type of intracellular membrane is actually targeted, remains poorly understood. Here, we found that the phase separation-mediated IRS-1 puncta attached to endoplasmic reticulum (ER). VAPB, an ER-anchored protein that mediates tethers between ER and membranes of other organelles, was identified as a direct interacting partner of IRS-1. VAPB mainly binds active IRS-1 because IGF-1 enhanced the VAPB-IRS-1 association and replacing of the nine tyrosine residues of YXXM motifs disrupted the VAPB-IRS-1 association. We further delineated that the Y745 and Y746 residues in the FFAT-like motif of IRS-1 mediated the association with VAPB. Notably, VAPB targeted IRS-1 to the ER and subsequently maintained its stability. Consistently, ablation of VAPB in mice led to downregulation of IRS-1, suppression of insulin signaling, and glucose intolerance. The amyotrophic lateral sclerosis (ALS)-derived VAPB P56S mutant also impaired IRS-1 stability by interfering with the ER-tethering of IRS-1. Our findings thus revealed a previously unappreciated condensate-membrane contact (CMC), by which VAPB stabilizes the membraneless IRS-1 signalosome through targeting it to ER membrane.
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Affiliation(s)
- Xiu Kui Gao
- Department of Biochemistry and Department of Orthopaedic Surgery of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
- International Institutes of Medicine, the Fourth Affiliated Hospital of Zhejiang University School of Medicine, Yiwu, Zhejiang, China.
- Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang Provincial Key Lab for Tissue Engineering and Regenerative Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
| | - Zu Kang Sheng
- Department of Biochemistry and Department of Orthopaedic Surgery of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang Provincial Key Lab for Tissue Engineering and Regenerative Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Ye Hong Lu
- Department of Biochemistry and Department of Orthopaedic Surgery of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang Provincial Key Lab for Tissue Engineering and Regenerative Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Yu Ting Sun
- Department of Biochemistry and Department of Orthopaedic Surgery of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang Provincial Key Lab for Tissue Engineering and Regenerative Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Xi Sheng Rao
- Department of Biochemistry and Department of Orthopaedic Surgery of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang Provincial Key Lab for Tissue Engineering and Regenerative Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Lin Jing Shi
- Department of Biochemistry and Department of Orthopaedic Surgery of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang Provincial Key Lab for Tissue Engineering and Regenerative Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Xiao Xia Cong
- Department of Biochemistry and Department of Orthopaedic Surgery of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang Provincial Key Lab for Tissue Engineering and Regenerative Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Xiao Chen
- Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang Provincial Key Lab for Tissue Engineering and Regenerative Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Hao Bo Wu
- Department of Biochemistry and Department of Orthopaedic Surgery of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Man Huang
- Department of Biochemistry and Department of General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejinag, China
- Key Laboratory of Multiple Organ Failure (Zhejiang University), Ministry of Education, Hangzhou, Zhejiang, China
| | - Qiang Zheng
- Department of Biochemistry and Department of Orthopaedic Surgery of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Jian-Sheng Guo
- Department of Pathology of Sir Run Run Shaw Hospital, Center of Cryo-Electron Microscopy, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Liang Jun Jiang
- Department of Biochemistry and Department of Orthopaedic Surgery of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
| | - Li Ling Zheng
- Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang Provincial Key Lab for Tissue Engineering and Regenerative Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
- Department of Biochemistry and Department of General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejinag, China.
- Key Laboratory of Multiple Organ Failure (Zhejiang University), Ministry of Education, Hangzhou, Zhejiang, China.
| | - Yi Ting Zhou
- Department of Biochemistry and Department of Orthopaedic Surgery of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
- Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang Provincial Key Lab for Tissue Engineering and Regenerative Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
- Key Laboratory of Multiple Organ Failure (Zhejiang University), Ministry of Education, Hangzhou, Zhejiang, China.
- ZJU-UoE Institute, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.
- Cancer Center, Zhejiang University, Hangzhou, Zhejiang, China.
- Liangzhu Laboratory, Hangzhou, Zhejiang, China.
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Rak M, Reiss K. Double Labeling Fluorescent Immunocytochemistry. Methods Mol Biol 2022; 2422:147-161. [PMID: 34859404 DOI: 10.1007/978-1-0716-1948-3_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Fluorescent immunocytochemistry is a powerful technique based on detecting antigens. It leads to discoveries in cell composition and structure as well as its functioning by expanding knowledge on colocalization between its components. The potency of this method is based on findings in the areas of specific antibodies production, fluorescent labels, and microscopy. Since it merges different fields, it requires basic knowledge on all the steps that are needed in the procedure planning and implementation to be used properly and produce reliable results. Here we describe a protocol of LN-229 human glioblastoma cells double labeling of LC3 and IRS-1 proteins, highlighting the importance of some steps of the procedure and possible variables.
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Affiliation(s)
- Monika Rak
- Department of Cell Biology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University in Kraków, Kraków, Poland.
- Departments of Medicine & Neurological Cancer Research, Louisiana Cancer Research Center, Louisiana State University Health Sciences Center, New Orleans, LA, USA.
| | - Krzysztof Reiss
- Departments of Medicine & Neurological Cancer Research, Louisiana Cancer Research Center, Louisiana State University Health Sciences Center, New Orleans, LA, USA
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Gu Y, Xia H, Chen X, Li J. Curcumin Nanoparticles Attenuate Lipotoxic Injury in Cardiomyocytes Through Autophagy and Endoplasmic Reticulum Stress Signaling Pathways. Front Pharmacol 2021; 12:571482. [PMID: 34456712 PMCID: PMC8386169 DOI: 10.3389/fphar.2021.571482] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 01/12/2021] [Indexed: 11/22/2022] Open
Abstract
Although curcumin (CUR) has many advantages, its hydrophobicity and instability limit its application. In this study, the anti-lipotoxic injury activity of CUR-loaded nanoparticles (CUR-NPs) and the corresponding mechanism were examined in palmitate (PA)-treated cardiomyocytes. An amphiphilic copolymer was selected as the vehicle material, and CUR-NPs with suitable sizes were prepared under optimized conditions. Cellular uptake was examined by confocal laser scanning microscopy, and cell proliferation inhibition rate was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetra bromide (MTT) assay. The terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay was used to detect cell apoptosis. The protein expression was detected by western blot. Exposure to PA reduces the proliferation of cardiomyocytes, but this effect was strongly reversed by CUR-NPs. In addition, our data showed that CUR-NPs strongly inhibited cell apoptosis in PA-treated cardiomyocytes. Furthermore, CUR-NPs remarkably increased the expression of LC3-II, as well as inhibited the expression of p-PERK, p-eIF2α, and ATF4 in PA-treated cardiomyocytes. Salubrinal (an eIF2α inhibitor) blocked the protective effect of CUR-NPs against PA-induced cardiomyocyte injury. Our results suggested that CUR-NPs can activated the autophagy pathway and protect myocardial cells from apoptosis, and these effects may be mediated by the eIF2α-related endoplasmic reticulum stress signaling pathway.
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Affiliation(s)
- Yue Gu
- Department of Reparatory and Critical Care Medicine, The First Affiliated Hospital of Jilin University, Changchun, China
| | - Huan Xia
- Department of Reparatory and Critical Care Medicine, The First Affiliated Hospital of Jilin University, Changchun, China
| | - Xiao Chen
- Hubei Province Key Laboratory on Cardiovascular, Cerebrovascular, and Metabolic Disorders, Hubei University of Science and Technology, Xianning, China
| | - Jing Li
- Medical College, Huzhou University, Huzhou, China
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Chemically Modified Variants of Fenofibrate with Antiglioblastoma Potential. Transl Oncol 2019; 12:895-907. [PMID: 31078963 PMCID: PMC6514324 DOI: 10.1016/j.tranon.2019.04.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 04/08/2019] [Accepted: 04/10/2019] [Indexed: 01/30/2023] Open
Abstract
Anticancer effects of a common lipid-lowering drug, fenofibrate, have been described in the literature for a quite some time; however, fenofibrate has not been used as a direct anticancer therapy. We have previously reported that fenofibrate in its unprocessed form (ester) accumulates in the mitochondria, inhibits mitochondrial respiration, and triggers a severe energy deficit and extensive glioblastoma cell death. However, fenofibrate does not cross the blood brain barrier and is quickly processed by blood and tissue esterases to form the PPARα agonist fenofibric acid, which is practically ineffective effective in triggering cancer cell death. To address these issues, we have made several chemical modifications in fenofibrate structure to increase its stability, water solubility, tissue penetration, and ultimately anticancer potential. Our data show that, in comparison to fenofibrate, four new compounds designated here as PP1, PP2, PP3, and PP4 have improved anticancer activity in vitro. Like fenofibrate, the compounds block mitochondrial respiration and trigger massive glioblastoma cell death in vitro. In addition, one of the lead compounds, PP1, has improved water solubility and is significantly more stable when exposed to human blood in comparison to fenofibrate. Importantly, mice bearing large intracranial glioblastoma tumors demonstrated extensive areas of tumor cell death within the tumor mass following oral administration of PP1, and the treated mice did not show any major signs of distress, and accumulated PP1 at therapeutically relevant concentrations in several tissues, including brain and intracranial tumors.
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