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Gao S, Carrasquillo Rodríguez JW, Bahmanyar S, Airola MV. Structure and mechanism of the human CTDNEP1-NEP1R1 membrane protein phosphatase complex necessary to maintain ER membrane morphology. Proc Natl Acad Sci U S A 2024; 121:e2321167121. [PMID: 38776370 PMCID: PMC11145253 DOI: 10.1073/pnas.2321167121] [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: 12/01/2023] [Accepted: 04/12/2024] [Indexed: 05/25/2024] Open
Abstract
C-terminal Domain Nuclear Envelope Phosphatase 1 (CTDNEP1) is a noncanonical protein serine/threonine phosphatase that has a conserved role in regulating ER membrane biogenesis. Inactivating mutations in CTDNEP1 correlate with the development of medulloblastoma, an aggressive childhood cancer. The transmembrane protein Nuclear Envelope Phosphatase 1 Regulatory Subunit 1 (NEP1R1) binds CTDNEP1, but the molecular details by which NEP1R1 regulates CTDNEP1 function are unclear. Here, we find that knockdown of NEP1R1 generates identical phenotypes to reported loss of CTDNEP1 in mammalian cells, establishing CTDNEP1-NEP1R1 as an evolutionarily conserved membrane protein phosphatase complex that restricts ER expansion. Mechanistically, NEP1R1 acts as an activating regulatory subunit that directly binds and increases the phosphatase activity of CTDNEP1. By defining a minimal NEP1R1 domain sufficient to activate CTDNEP1, we determine high-resolution crystal structures of the CTDNEP1-NEP1R1 complex bound to a peptide sequence acting as a pseudosubstrate. Structurally, NEP1R1 engages CTDNEP1 at a site distant from the active site to stabilize and allosterically activate CTDNEP1. Substrate recognition is facilitated by a conserved Arg residue in CTDNEP1 that binds and orients the substrate peptide in the active site. Together, this reveals mechanisms for how NEP1R1 regulates CTDNEP1 and explains how cancer-associated mutations inactivate CTDNEP1.
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Affiliation(s)
- Shujuan Gao
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY11794
| | | | - Shirin Bahmanyar
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT06511
| | - Michael V. Airola
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY11794
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2
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Gao S, Carrasquillo Rodríguez JW, Bahmanyar S, Airola MV. Structure and mechanism of the human CTDNEP1-NEP1R1 membrane protein phosphatase complex necessary to maintain ER membrane morphology. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.20.567952. [PMID: 38045299 PMCID: PMC10690229 DOI: 10.1101/2023.11.20.567952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
C-terminal Domain Nuclear Envelope Phosphatase 1 (CTDNEP1) is a non-canonical protein serine/threonine phosphatase that regulates ER membrane biogenesis. Inactivating mutations in CTDNEP1 correlate with development of medulloblastoma, an aggressive childhood cancer. The transmembrane protein Nuclear Envelope Phosphatase 1 Regulatory Subunit 1 (NEP1R1) binds CTDNEP1, but the molecular details by which NEP1R1 regulates CTDNEP1 function are unclear. Here, we find that knockdown of CTDNEP1 or NEP1R1 in human cells generate identical phenotypes, establishing CTDNEP1-NEP1R1 as an evolutionarily conserved membrane protein phosphatase complex that restricts ER expansion. Mechanistically, NEP1R1 acts as an activating regulatory subunit that directly binds and increases the phosphatase activity of CTDNEP1. By defining a minimal NEP1R1 domain sufficient to activate CTDNEP1, we determine high resolution crystal structures of the CTDNEP1-NEP1R1 complex bound to a pseudo-substrate. Structurally, NEP1R1 engages CTDNEP1 at a site distant from the active site to stabilize and allosterically activate CTDNEP1. Substrate recognition is facilitated by a conserved Arg residue that binds and orients the substrate peptide in the active site. Together, this reveals mechanisms for how NEP1R1 regulates CTDNEP1 and explains how cancer-associated mutations inactivate CTDNEP1.
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Affiliation(s)
- Shujuan Gao
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook NY 11794, USA
| | | | - Shirin Bahmanyar
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - Michael V. Airola
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook NY 11794, USA
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3
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Ding Z, Song H, Wang F. Role of lipins in cardiovascular diseases. Lipids Health Dis 2023; 22:196. [PMID: 37964368 PMCID: PMC10644651 DOI: 10.1186/s12944-023-01961-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Accepted: 11/01/2023] [Indexed: 11/16/2023] Open
Abstract
Lipin family members in mammals include lipins 1, 2, and 3. Lipin family proteins play a crucial role in lipid metabolism due to their bifunctionality as both transcriptional coregulators and phosphatidate phosphatase (PAP) enzymes. In this review, we discuss the structural features, expression patterns, and pathophysiologic functions of lipins, emphasizing their direct as well as indirect roles in cardiovascular diseases (CVDs). Elucidating the regulation of lipins facilitates a deeper understanding of the roles of lipins in the processes underlying CVDs. The activity of lipins is modulated at various levels, e.g., in the form of the transcription of genes, post-translational modifications, and subcellular protein localization. Because lipin characteristics are undergoing progressive clarification, further research is necessitated to then actuate the investigation of lipins as viable therapeutic targets in CVDs.
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Affiliation(s)
- Zerui Ding
- The Endocrinology Department of the Third Xiangya Hospital, Central South University, Changsha, 410013, China
- Xiangya School of Medicine, Central South University, Changsha, 410013, China
| | - Hongyu Song
- The Endocrinology Department of the Third Xiangya Hospital, Central South University, Changsha, 410013, China
- Xiangya School of Medicine, Central South University, Changsha, 410013, China
| | - Fang Wang
- The Endocrinology Department of the Third Xiangya Hospital, Central South University, Changsha, 410013, China.
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4
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Un Nisa M, Gillani SQ, Nabi N, Sarwar Z, Reshi I, Bhat SA, Andrabi S. Lipin-1 stability and its adipogenesis functions are regulated in contrasting ways by AKT1 and LKB1. J Cell Commun Signal 2023; 17:689-704. [PMID: 36380131 PMCID: PMC10409976 DOI: 10.1007/s12079-022-00708-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 10/24/2022] [Indexed: 11/16/2022] Open
Abstract
Lipin-1 is a protein that plays a critical role in many cellular functions. At molecular level, it acts as a phosphatidic acid phosphohydrolase and a transcriptional coactivator. The functions of lipin-1 are largely dependent upon its subcellular localization, post-translational modifications like phosphorylation and acetylation, and also on its interaction with other proteins such as 14-3-3. However, the kinases and phosphatases that are responsible for these post translational modifications are not entirely known. Using bioinformatics and other biochemical approaches, we demonstrate lipin-1 as a novel target for AKT1 and LKB1. While AKT1 stabilizes lipin-1, LKB1 causes its degradation. Interestingly, our findings further show that lipin-1 enhances AKT1 activity as can be seen by increased phosphorylation of the substrates of AKT1. Taken together, our results suggest that lipin-1 plays an important role in the regulation of PI3K-AKT-mTOR pathway, which is dysregulated in majority of cancers. Therefore, understating the role of lipin-1 may provide new and important insights into the regulation and functions of the PI3K-mTOR pathway, which is one of the major targets for anti-cancer drug development strategies.
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Affiliation(s)
- Misbah Un Nisa
- Department of Biochemistry, University of Kashmir, Srinagar, 190006, India
| | | | - Nusrat Nabi
- Department of Biochemistry, University of Kashmir, Srinagar, 190006, India
| | - Zarka Sarwar
- Department of Biochemistry, University of Kashmir, Srinagar, 190006, India
| | - Irfana Reshi
- Department of Biotechnology, University of Kashmir, Srinagar, 190006, India
| | - Sameer Ahmed Bhat
- Department of Biotechnology, University of Kashmir, Srinagar, 190006, India
| | - Shaida Andrabi
- Department of Biochemistry, University of Kashmir, Srinagar, 190006, India.
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5
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Nicastro R, Brohée L, Alba J, Nüchel J, Figlia G, Kipschull S, Gollwitzer P, Romero-Pozuelo J, Fernandes SA, Lamprakis A, Vanni S, Teleman AA, De Virgilio C, Demetriades C. Malonyl-CoA is a conserved endogenous ATP-competitive mTORC1 inhibitor. Nat Cell Biol 2023; 25:1303-1318. [PMID: 37563253 PMCID: PMC10495264 DOI: 10.1038/s41556-023-01198-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 06/29/2023] [Indexed: 08/12/2023]
Abstract
Cell growth is regulated by the mammalian/mechanistic target of rapamycin complex 1 (mTORC1), which functions both as a nutrient sensor and a master controller of virtually all biosynthetic pathways. This ensures that cells are metabolically active only when conditions are optimal for growth. Notably, although mTORC1 is known to regulate fatty acid biosynthesis, how and whether the cellular lipid biosynthetic capacity signals back to fine-tune mTORC1 activity remains poorly understood. Here we show that mTORC1 senses the capacity of a cell to synthesise fatty acids by detecting the levels of malonyl-CoA, an intermediate of this biosynthetic pathway. We find that, in both yeast and mammalian cells, this regulation is direct, with malonyl-CoA binding to the mTOR catalytic pocket and acting as a specific ATP-competitive inhibitor. When fatty acid synthase (FASN) is downregulated/inhibited, elevated malonyl-CoA levels are channelled to proximal mTOR molecules that form direct protein-protein interactions with acetyl-CoA carboxylase 1 (ACC1) and FASN. Our findings represent a conserved and unique homeostatic mechanism whereby impaired fatty acid biogenesis leads to reduced mTORC1 activity to coordinately link this metabolic pathway to the overall cellular biosynthetic output. Moreover, they reveal the existence of a physiological metabolite that directly inhibits the activity of a signalling kinase in mammalian cells by competing with ATP for binding.
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Affiliation(s)
- Raffaele Nicastro
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Laura Brohée
- Max Planck Institute for Biology of Ageing (MPI-AGE), Cologne, Germany
| | - Josephine Alba
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Julian Nüchel
- Max Planck Institute for Biology of Ageing (MPI-AGE), Cologne, Germany
| | - Gianluca Figlia
- German Cancer Research Center (DKFZ), Heidelberg, Germany
- Heidelberg University, Heidelberg, Germany
| | | | - Peter Gollwitzer
- Max Planck Institute for Biology of Ageing (MPI-AGE), Cologne, Germany
| | - Jesus Romero-Pozuelo
- German Cancer Research Center (DKFZ), Heidelberg, Germany
- Heidelberg University, Heidelberg, Germany
- Unidad de Investigación Biomedica, Universidad Alfonso X El Sabio (UAX), Madrid, Spain
| | | | - Andreas Lamprakis
- Max Planck Institute for Biology of Ageing (MPI-AGE), Cologne, Germany
| | - Stefano Vanni
- Department of Biology, University of Fribourg, Fribourg, Switzerland.
| | - Aurelio A Teleman
- German Cancer Research Center (DKFZ), Heidelberg, Germany.
- Heidelberg University, Heidelberg, Germany.
| | | | - Constantinos Demetriades
- Max Planck Institute for Biology of Ageing (MPI-AGE), Cologne, Germany.
- University of Cologne, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne, Germany.
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6
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Saik NO, Ptak C, Rehman S, Aitchison JD, Montpetit B, Wozniak RW. SUMOylation at the inner nuclear membrane facilitates nuclear envelope biogenesis during mitosis. J Cell Biol 2023; 222:e202208137. [PMID: 37398994 PMCID: PMC10318406 DOI: 10.1083/jcb.202208137] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 03/24/2023] [Accepted: 05/15/2023] [Indexed: 07/04/2023] Open
Abstract
As eukaryotic cells progress through cell division, the nuclear envelope (NE) membrane must expand to accommodate the formation of progeny nuclei. In Saccharomyces cerevisiae, closed mitosis allows visualization of NE biogenesis during mitosis. During this period, the SUMO E3 ligase Siz2 binds the inner nuclear membrane (INM) and initiates a wave of INM protein SUMOylation. Here, we show these events increase INM levels of phosphatidic acid (PA), an intermediate of phospholipid biogenesis, and are necessary for normal mitotic NE membrane expansion. The increase in INM PA is driven by the Siz2-mediated inhibition of the PA phosphatase Pah1. During mitosis, this results from the binding of Siz2 to the INM and dissociation of Spo7 and Nem1, a complex required for the activation of Pah1. As cells enter interphase, the process is then reversed by the deSUMOylase Ulp1. This work further establishes a central role for temporally controlled INM SUMOylation in coordinating processes, including membrane expansion, that regulate NE biogenesis during mitosis.
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Affiliation(s)
- Natasha O. Saik
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
| | - Christopher Ptak
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
| | - Saif Rehman
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
| | - John D. Aitchison
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
- Seattle Children’s Research Institute, Seattle, WA, USA
- Department of Pediatrics and Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Ben Montpetit
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
- Department of Viticulture and Enology, University of California Davis, Davis, CA, USA
| | - Richard W. Wozniak
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
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7
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Stukey GJ, Han GS, Carman GM. Phosphatidate phosphatase Pah1 contains a novel RP domain that regulates its phosphorylation and function in yeast lipid synthesis. J Biol Chem 2023; 299:105025. [PMID: 37423305 PMCID: PMC10406625 DOI: 10.1016/j.jbc.2023.105025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 06/30/2023] [Accepted: 07/02/2023] [Indexed: 07/11/2023] Open
Abstract
The Saccharomyces cerevisiae PAH1-encoded phosphatidate (PA) phosphatase, which catalyzes the Mg2+-dependent dephosphorylation of PA to produce diacylglycerol, is one of the most highly regulated enzymes in lipid metabolism. The enzyme controls whether cells utilize PA to produce membrane phospholipids or the major storage lipid triacylglycerol. PA levels, which are regulated by the enzyme reaction, also control the expression of UASINO-containing phospholipid synthesis genes via the Henry (Opi1/Ino2-Ino4) regulatory circuit. Pah1 function is largely controlled by its cellular location, which is mediated by phosphorylation and dephosphorylation. Multiple phosphorylations sequester Pah1 in the cytosol and protect it from 20S proteasome-mediated degradation. The endoplasmic reticulum-associated Nem1-Spo7 phosphatase complex recruits and dephosphorylates Pah1 allowing the enzyme to associate with and dephosphorylate its membrane-bound substrate PA. Pah1 contains domains/regions that include the N-LIP and haloacid dehalogenase-like catalytic domains, N-terminal amphipathic helix for membrane binding, C-terminal acidic tail for Nem1-Spo7 interaction, and a conserved tryptophan within the WRDPLVDID domain required for enzyme function. Through bioinformatics, molecular genetics, and biochemical approaches, we identified a novel RP (regulation of phosphorylation) domain that regulates the phosphorylation state of Pah1. We showed that the ΔRP mutation results in a 57% reduction in the endogenous phosphorylation of the enzyme (primarily at Ser-511, Ser-602, and Ser-773/Ser-774), an increase in membrane association and PA phosphatase activity, but reduced cellular abundance. This work not only identifies a novel regulatory domain within Pah1 but emphasizes the importance of the phosphorylation-based regulation of Pah1 abundance, location, and function in yeast lipid synthesis.
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Affiliation(s)
- Geordan J Stukey
- Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey, USA
| | - Gil-Soo Han
- Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey, USA
| | - George M Carman
- Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey, USA.
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8
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Doxsey DD, Tettoni SD, Egri SB, Shen K. Redundant electrostatic interactions between GATOR1 and the Rag GTPase heterodimer drive efficient amino acid sensing in human cells. J Biol Chem 2023; 299:104880. [PMID: 37269949 PMCID: PMC10316081 DOI: 10.1016/j.jbc.2023.104880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 05/23/2023] [Accepted: 05/25/2023] [Indexed: 06/05/2023] Open
Abstract
Cells need to coordinate nutrient availability with their growth and proliferation. In eukaryotic cells, this coordination is mediated by the mechanistic target of the rapamycin complex 1 (mTORC1) pathway. mTORC1 activation is regulated by two GTPase units, the Rag GTPase heterodimer and the Rheb GTPase. The RagA-RagC heterodimer controls the subcellular localization of mTORC1, and its nucleotide loading states are strictly controlled by upstream regulators including amino acid sensors. A critical negative regulator of the Rag GTPase heterodimer is GATOR1. In the absence of amino acids, GATOR1 stimulates GTP hydrolysis by the RagA subunit to turn off mTORC1 signaling. Despite the enzymatic specificity of GATOR1 to RagA, a recent cryo-EM structural model of the human GATOR1-Rag-Ragulator complex reveals an unexpected interface between Depdc5, a subunit of GATOR1, and RagC. Currently, there is no functional characterization of this interface, nor do we know its biological relevance. Here, combining structure-function analysis, enzymatic kinetic measurements, and cell-based signaling assays, we identified a critical electrostatic interaction between Depdc5 and RagC. This interaction is mediated by the positively charged Arg-1407 residue on Depdc5 and a patch of negatively charged residues on the lateral side of RagC. Abrogating this interaction impairs the GAP activity of GATOR1 and cellular response to amino acid withdrawal. Our results reveal how GATOR1 coordinates the nucleotide loading states of the Rag GTPase heterodimer, and thus precisely controls cellular behavior in the absence of amino acids.
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Affiliation(s)
- Dylan D Doxsey
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Steven D Tettoni
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Shawn B Egri
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Kuang Shen
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA; Department of Biochemistry & Molecular Pharmacology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA.
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9
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Rallabandi HR, Choi H, Cha H, Kim YJ. Research Trends in C-Terminal Domain Nuclear Envelope Phosphatase 1. Life (Basel) 2023; 13:1338. [PMID: 37374122 DOI: 10.3390/life13061338] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 05/31/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
C-terminal domain nuclear envelope phosphatase 1 (CTDNEP1, formerly Dullard) is a member of the newly emerging protein phosphatases and has been recognized in neuronal cell tissues in amphibians. It contains the phosphatase domain in the C-terminal, and the sequences are conserved in various taxa of organisms. CTDNEP1 has several roles in novel biological activities such as neural tube development in embryos, nuclear membrane biogenesis, regulation of bone morphogenetic protein signaling, and suppression of aggressive medulloblastoma. The three-dimensional structure of CTDNEP1 and the detailed action mechanisms of CTDNEP1's functions have yet to be determined for several reasons. Therefore, CTDNEP1 is a protein phosphatase of interest due to recent exciting and essential works. In this short review, we summarize the presented biological roles, possible substrates, interacting proteins, and research prospects of CTDNEP1.
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Affiliation(s)
- Harikrishna Reddy Rallabandi
- Department of Medicinal Bioscience and Nanotechnology Research Center, Konkuk University, Chungju 27478, Republic of Korea
| | - Haewon Choi
- Department of Medicinal Bioscience and Nanotechnology Research Center, Konkuk University, Chungju 27478, Republic of Korea
| | - Hyunseung Cha
- Department of Medicinal Bioscience and Nanotechnology Research Center, Konkuk University, Chungju 27478, Republic of Korea
| | - Young Jun Kim
- Department of Medicinal Bioscience and Nanotechnology Research Center, Konkuk University, Chungju 27478, Republic of Korea
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10
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Santana-Sosa S, Matos-Perdomo E, Ayra-Plasencia J, Machín F. A Yeast Mitotic Tale for the Nucleus and the Vacuoles to Embrace. Int J Mol Sci 2023; 24:9829. [PMID: 37372977 DOI: 10.3390/ijms24129829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 06/02/2023] [Accepted: 06/03/2023] [Indexed: 06/29/2023] Open
Abstract
The morphology of the nucleus is roughly spherical in most eukaryotic cells. However, this organelle shape needs to change as the cell travels through narrow intercellular spaces during cell migration and during cell division in organisms that undergo closed mitosis, i.e., without dismantling the nuclear envelope, such as yeast. In addition, the nuclear morphology is often modified under stress and in pathological conditions, being a hallmark of cancer and senescent cells. Thus, understanding nuclear morphological dynamics is of uttermost importance, as pathways and proteins involved in nuclear shaping can be targeted in anticancer, antiaging, and antifungal therapies. Here, we review how and why the nuclear shape changes during mitotic blocks in yeast, introducing novel data that associate these changes with both the nucleolus and the vacuole. Altogether, these findings suggest a close relationship between the nucleolar domain of the nucleus and the autophagic organelle, which we also discuss here. Encouragingly, recent evidence in tumor cell lines has linked aberrant nuclear morphology to defects in lysosomal function.
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Affiliation(s)
- Silvia Santana-Sosa
- Research Unit, University Hospital Ntra Sra de Candelaria, Ctra del Rosario 145, 38010 Santa Cruz de Tenerife, Spain
- Institute of Biomedical Technologies, University of La Laguna, 38200 San Cristóbal de La Laguna, Spain
| | - Emiliano Matos-Perdomo
- Research Unit, University Hospital Ntra Sra de Candelaria, Ctra del Rosario 145, 38010 Santa Cruz de Tenerife, Spain
- Institute of Biomedical Technologies, University of La Laguna, 38200 San Cristóbal de La Laguna, Spain
| | - Jessel Ayra-Plasencia
- Research Unit, University Hospital Ntra Sra de Candelaria, Ctra del Rosario 145, 38010 Santa Cruz de Tenerife, Spain
- Institute of Biomedical Technologies, University of La Laguna, 38200 San Cristóbal de La Laguna, Spain
| | - Félix Machín
- Research Unit, University Hospital Ntra Sra de Candelaria, Ctra del Rosario 145, 38010 Santa Cruz de Tenerife, Spain
- Institute of Biomedical Technologies, University of La Laguna, 38200 San Cristóbal de La Laguna, Spain
- Faculty of Health Sciences, Fernando Pessoa Canarias University, 35450 Santa María de Guía, Spain
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11
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Zhang G, Xu Y, Xia Y, Wang G, Zhao H. Transcriptomic Analysis of Hepatotoxicology of Adult Zebrafish (Danio rerio) Exposed to Environmentally Relevant Oxytetracycline. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2022; 82:539-550. [PMID: 35460351 DOI: 10.1007/s00244-022-00930-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 03/29/2022] [Indexed: 06/14/2023]
Abstract
The extensive use of the broad-spectrum antibiotics like oxytetracycline (OTC) has become a serious environmental issue globally. OTC has profound negative effects on aquatic organisms including fishes. In this study, RNA-Seq analysis was employed to examine the possible molecular mechanism of hepatotoxicology in zebrafish induced by OTC exposure. Adult male zebrafish was exposed to 0, 5, 90, and 450 μg/L OTC for 3 weeks. The results showed the decrease in body weight and tail length but the increase in total length of zebrafish under OTC exposure in a dose-dependent way. In addition, severe histopathological damages were featured by increasing tissue vacuolization in the livers of 450 μg/L OTC group. Moreover, RNA-Seq analysis revealed that molecular signaling and functional pathways in the liver were disrupted by OTC exposure. Furthermore, the down-regulation of gene expression after OTC exposure was found on both the genes related to fatty acid degradation and the genes related to lipid synthesis. The present study implied that OTC induced liver malfunction and fish health risks through growth retard, histopathological damages, molecular signaling disruption, genetic expression alteration, and lipid metabolism disturbance.
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Affiliation(s)
- Gaixia Zhang
- Collge of Life Sciences, Shaanxi Normal University, No. 620, West Chang'an Avenue, Chang'an District, Xi'an, 710119, Shaanxi, China
| | - Yifan Xu
- AP Center, Changzhou Senior High School of Jiangsu Province, No. 8, Luohan Road, Tianning District, Changzhou, 213004, Jiangsu, China
| | - Youran Xia
- Changzhou No. 2 High School, No. 32, Xiheng Street, Zhonglou District, Changzhou, 213001, Jiangsu, China
| | - Gang Wang
- AP Center, Changzhou Senior High School of Jiangsu Province, No. 8, Luohan Road, Tianning District, Changzhou, 213004, Jiangsu, China
| | - Hongfeng Zhao
- Collge of Life Sciences, Shaanxi Normal University, No. 620, West Chang'an Avenue, Chang'an District, Xi'an, 710119, Shaanxi, China.
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12
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Doxsey DD, Veinotte K, Shen K. A New Crosslinking Assay to Study Guanine Nucleotide Binding in the Gtr Heterodimer of S. cerevisiae. Small GTPases 2022; 13:327-334. [PMID: 36328771 PMCID: PMC9639563 DOI: 10.1080/21541248.2022.2141019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mechanistic target of rapamycin (mTOR) complex is responsible for coordinating nutrient availability with eukaryotic cell growth. Amino acid signals are transmitted towards mTOR via the Rag/Gtr heterodimers. Due to the obligatory heterodimeric architecture of the Rag/Gtr GTPases, investigating their biochemical properties has been challenging. Here, we describe an updated assay that allows us to probe the guanine nucleotide-binding affinity and kinetics to the Gtr heterodimers in Saccharomyces cerevisiae. We first identified the structural element that Gtr2p lacks to enable crosslinking. By using a sequence conservation-based mutation, we restored the crosslinking between Gtr2p and the bound nucleotides. Using this construct, we determined the nucleotide-binding affinities of the Gtr heterodimer, and found that it operates under a different form of intersubunit communication than human Rag GTPases. Our study defines the evolutionary divergence of the Gtr/Rag-mTOR axis of nutrient sensing.
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Affiliation(s)
- Dylan D. Doxsey
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, 373 Plantation St, Worcester, MA, 01605, USA
| | - Kristen Veinotte
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, 373 Plantation St, Worcester, MA, 01605, USA
| | - Kuang Shen
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, 373 Plantation St, Worcester, MA, 01605, USA,Department of Biochemistry & Molecular Biotechnology, University of Massachusetts Chan Medical School, 364 Plantation St, Worcester, MA, 01605, USA,CONTACT Kuang Shen Program in Molecular Medicine, University of Massachusetts Chan Medical School, 373 Plantation St, Worcester, MA, 01605, USA
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Kakehi S, Tamura Y, Ikeda SI, Kaga N, Taka H, Ueno N, Shiuchi T, Kubota A, Sakuraba K, Kawamori R, Watada H. Short-term physical inactivity induces diacylglycerol accumulation and insulin resistance in muscle via lipin1 activation. Am J Physiol Endocrinol Metab 2021; 321:E766-E781. [PMID: 34719943 DOI: 10.1152/ajpendo.00254.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Physical inactivity impairs muscle insulin sensitivity. However, its mechanism is unclear. To model physical inactivity, we applied 24-h hind-limb cast immobilization (HCI) to mice with normal or high-fat diet (HFD) and evaluated intramyocellular lipids and the insulin signaling pathway in the soleus muscle. Although 2-wk HFD alone did not alter intramyocellular diacylglycerol (IMDG) accumulation, HCI alone increased it by 1.9-fold and HCI after HFD further increased it by 3.3-fold. Parallel to this, we found increased protein kinase C ε (PKCε) activity, reduced insulin-induced 2-deoxyglucose (2-DOG) uptake, and reduced phosphorylation of insulin receptor β (IRβ) and Akt, key molecules for insulin signaling pathway. Lipin1, which converts phosphatidic acid to diacylglycerol, showed increase of its activity by HCI, and dominant-negative lipin1 expression in muscle prevented HCI-induced IMDG accumulation and impaired insulin-induced 2-DOG uptake. Furthermore, 24-h leg cast immobilization in human increased lipin1 expression. Thus, even short-term immobilization increases IMDG and impairs insulin sensitivity in muscle via enhanced lipin1 activity.NEW & NOTEWORTHY Physical inactivity impairs muscle insulin sensitivity. However, its mechanism is unclear. To model physical inactivity, we applied 24-h hind-limb cast immobilization to mice with normal or high-fat diet and evaluated intramyocellular lipids and the insulin signaling pathway in the soleus muscle. We found that even short-term immobilization increases intramyocellular diacylglycerol and impairs insulin sensitivity in muscle via enhanced lipin1 activity.
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Affiliation(s)
- Saori Kakehi
- Department of Metabolism and Endocrinology, Graduate School of Medicine, Juntendo University, Tokyo, Japan
- Sportology Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Yoshifumi Tamura
- Department of Metabolism and Endocrinology, Graduate School of Medicine, Juntendo University, Tokyo, Japan
- Sportology Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Shin-Ichi Ikeda
- Department of Metabolism and Endocrinology, Graduate School of Medicine, Juntendo University, Tokyo, Japan
- Sportology Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Naoko Kaga
- Laboratory of Proteomics and Biomolecular Science, Biomedical Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Hikari Taka
- Laboratory of Proteomics and Biomolecular Science, Biomedical Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Noriko Ueno
- Laboratory of Proteomics and Biomolecular Science, Biomedical Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Tetsuya Shiuchi
- Department of Integrative Physiology, Institute for Health Biosciences, University of Tokushima Graduate School, Tokushima, Japan
| | - Atsushi Kubota
- Department of Sports Medicine, Juntendo University, Chiba, Japan
| | | | - Ryuzo Kawamori
- Department of Metabolism and Endocrinology, Graduate School of Medicine, Juntendo University, Tokyo, Japan
- Sportology Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Hirotaka Watada
- Department of Metabolism and Endocrinology, Graduate School of Medicine, Juntendo University, Tokyo, Japan
- Sportology Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan
- Center for Therapeutic Innovations in Diabetes, Graduate School of Medicine, Juntendo University, Tokyo, Japan
- Center for Identification of Diabetic Therapeutic Targets, Graduate School of Medicine, Juntendo University, Tokyo, Japan
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14
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Gu W, Gao S, Wang H, Fleming KD, Hoffmann RM, Yang JW, Patel NM, Choi YM, Burke JE, Reue K, Airola MV. The middle lipin domain adopts a membrane-binding dimeric protein fold. Nat Commun 2021; 12:4718. [PMID: 34354069 PMCID: PMC8342540 DOI: 10.1038/s41467-021-24929-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 07/13/2021] [Indexed: 02/06/2023] Open
Abstract
Phospholipid synthesis and fat storage as triglycerides are regulated by lipin phosphatidic acid phosphatases (PAPs), whose enzymatic PAP function requires association with cellular membranes. Using hydrogen deuterium exchange mass spectrometry, we find mouse lipin 1 binds membranes through an N-terminal amphipathic helix, the Ig-like domain and HAD phosphatase catalytic core, and a middle lipin (M-Lip) domain that is conserved in mammalian and mammalian-like lipins. Crystal structures of the M-Lip domain reveal a previously unrecognized protein fold that dimerizes. The isolated M-Lip domain binds membranes both in vitro and in cells through conserved basic and hydrophobic residues. Deletion of the M-Lip domain in lipin 1 reduces PAP activity, membrane association, and oligomerization, alters subcellular localization, diminishes acceleration of adipocyte differentiation, but does not affect transcriptional co-activation. This establishes the M-Lip domain as a dimeric protein fold that binds membranes and is critical for full functionality of mammalian lipins.
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Affiliation(s)
- Weijing Gu
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, USA
| | - Shujuan Gao
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, USA
| | - Huan Wang
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Kaelin D Fleming
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - Reece M Hoffmann
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - Jong Won Yang
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, USA
| | - Nimi M Patel
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, USA
| | - Yong Mi Choi
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, USA
| | - John E Burke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - Karen Reue
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
| | - Michael V Airola
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, USA.
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15
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Chambers KT, Cooper MA, Swearingen AR, Brookheart RT, Schweitzer GG, Weinheimer CJ, Kovacs A, Koves TR, Muoio DM, McCommis KS, Finck BN. Myocardial Lipin 1 knockout in mice approximates cardiac effects of human LPIN1 mutations. JCI Insight 2021; 6:134340. [PMID: 33986192 PMCID: PMC8262319 DOI: 10.1172/jci.insight.134340] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 03/31/2021] [Indexed: 11/17/2022] Open
Abstract
Lipin 1 is a bifunctional protein that is a transcriptional regulator and has phosphatidic acid (PA) phosphohydrolase activity, which dephosphorylates PA to generate diacylglycerol. Human lipin 1 mutations lead to episodic rhabdomyolysis, and some affected patients exhibit cardiac abnormalities, including exercise-induced cardiac dysfunction and cardiac triglyceride accumulation. Furthermore, lipin 1 expression is deactivated in failing heart, but the effects of lipin 1 deactivation in myocardium are incompletely understood. We generated mice with cardiac-specific lipin 1 KO (cs-Lpin1-/-) to examine the intrinsic effects of lipin 1 in the myocardium. Cs-Lpin1-/- mice had normal systolic cardiac function but mild cardiac hypertrophy. Compared with littermate control mice, PA content was higher in cs-Lpin1-/- hearts, which also had an unexpected increase in diacylglycerol and triglyceride content. Cs-Lpin1-/- mice exhibited diminished cardiac cardiolipin content and impaired mitochondrial respiration rates when provided with pyruvate or succinate as metabolic substrates. After transverse aortic constriction-induced pressure overload, loss of lipin 1 did not exacerbate cardiac hypertrophy or dysfunction. However, loss of lipin 1 dampened the cardiac ionotropic response to dobutamine and exercise endurance in association with reduced protein kinase A signaling. These data suggest that loss of lipin 1 impairs cardiac functional reserve, likely due to effects on glycerolipid homeostasis, mitochondrial function, and protein kinase A signaling.
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Affiliation(s)
- Kari T Chambers
- Division of Geriatrics and Nutritional Science, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Michael A Cooper
- Division of Geriatrics and Nutritional Science, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Alison R Swearingen
- Division of Geriatrics and Nutritional Science, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Rita T Brookheart
- Division of Geriatrics and Nutritional Science, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - George G Schweitzer
- Division of Geriatrics and Nutritional Science, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Carla J Weinheimer
- Division of Geriatrics and Nutritional Science, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Attila Kovacs
- Division of Geriatrics and Nutritional Science, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Timothy R Koves
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Departments of Medicine and Pharmacology and Cancer Biology, Duke University, Durham, North Carolina, USA
| | - Deborah M Muoio
- Duke Molecular Physiology Institute and Sarah W. Stedman Nutrition and Metabolism Center, Departments of Medicine and Pharmacology and Cancer Biology, Duke University, Durham, North Carolina, USA
| | - Kyle S McCommis
- Department of Biochemistry & Molecular Biology, Saint Louis University School of Medicine, St. Louis, Missouri, USA
| | - Brian N Finck
- Division of Geriatrics and Nutritional Science, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
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16
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Vernieri C, Nichetti F, Lalli L, Moscetti L, Giorgi CA, Griguolo G, Marra A, Randon G, Rea CG, Ligorio F, Scagnoli S, De Angelis C, Molinelli C, Fabbri A, Ferraro E, Trapani D, Milani A, Agostinetto E, Bernocchi O, Catania G, Vantaggiato A, Palleschi M, Moretti A, Basile D, Cinausero M, Ajazi A, Castagnoli L, Lo Vullo S, Gerratana L, Puglisi F, La Verde N, Arpino G, Rocca A, Ciccarese M, Pedersini R, Fabi A, Generali D, Losurdo A, Montemurro F, Curigliano G, Del Mastro L, Michelotti A, Cortesi E, Guarneri V, Pruneri G, Mariani L, de Braud F. Impact of Baseline and On-Treatment Glycemia on Everolimus-Exemestane Efficacy in Patients with Hormone Receptor-Positive Advanced Breast Cancer (EVERMET). Clin Cancer Res 2021; 27:3443-3455. [PMID: 33785482 DOI: 10.1158/1078-0432.ccr-20-4928] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/24/2021] [Accepted: 03/26/2021] [Indexed: 11/16/2022]
Abstract
PURPOSE The mTOR complex C1 (mTORC1) inhibitor everolimus in combination with the aromatase inhibitor exemestane is an effective treatment for patients with hormone receptor-positive (HR+), HER2-negative (HER2-), advanced breast cancer (HR+/HER2- aBC). However, everolimus can cause hyperglycemia and hyperinsulinemia, which could reactivate the PI3K/protein kinase B (AKT)/mTORC1 pathway and induce tumor resistance to everolimus. EXPERIMENTAL DESIGN We conducted a multicenter, retrospective, Italian study to investigate the impact of baseline and on-treatment (i.e., during first 3 months of therapy) blood glucose levels on progression-free survival (PFS) in patients with HR+/HER2- aBC treated with everolimus-exemestane. RESULTS We evaluated 809 patients with HR+/HER2- aBC treated with everolimus-exemestane as any line of therapy for advanced disease. When evaluated as dichotomous variables, baseline and on-treatment glycemia were not significantly associated with PFS. However, when blood glucose concentration was evaluated as a continuous variable, a multivariable model accounting for clinically relevant patient- and tumor-related variables revealed that both baseline and on-treatment glycemia are associated with PFS, and this association is largely attributable to their interaction. In particular, patients who are normoglycemic at baseline and experience on-treatment diabetes have lower PFS compared with patients who are already hyperglycemic at baseline and experience diabetes during everolimus-exemestane therapy (median PFS, 6.34 vs. 10.32 months; HR, 1.76; 95% confidence interval, 1.15-2.69; P = 0.008). CONCLUSIONS The impact of on-treatment glycemia on the efficacy of everolimus-exemestane therapy in patients with HR+/HER2- aBC depends on baseline glycemia. This study lays the foundations for investigating novel therapeutic approaches to target the glucose/insulin axis in combination with PI3K/AKT/mTORC1 inhibitors in patients with HR+/HER2- aBC.
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Affiliation(s)
- Claudio Vernieri
- Department of Medical Oncology, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy. .,IFOM, the FIRC Institute of Molecular Oncology, Milan, Italy
| | - Federico Nichetti
- Department of Medical Oncology, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Luca Lalli
- Unit of Clinical Epidemiology and Trial Organization, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Luca Moscetti
- Division of Medical Oncology, Department of Oncology and Hematology, University Hospital of Modena, Modena, Italy
| | | | - Gaia Griguolo
- Medical Oncology 2, Veneto Institute of Oncology IOV - IRCCS, Padua, Italy.,Department of Surgery, Oncology and Gastroenterology, University of Padova, Padua, Italy
| | - Antonio Marra
- Division of Early Drug Development for Innovative Therapies, IEO, European Institute of Oncology IRCCS, Milan, Italy
| | - Giovanni Randon
- Department of Medical Oncology, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Carmen G Rea
- Department of Medical Oncology, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Francesca Ligorio
- Department of Medical Oncology, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Simone Scagnoli
- Department of Medico-Surgical Sciences and Translational Medicine, "Sapienza" University of Rome, Rome, Italy
| | - Claudia De Angelis
- UO Oncologia Medica 2, Ospedale S. Chiara, Dipartimento di Oncologia, Dei Trapianti e Delle Nuove Tecnologie, Azienda Ospedaliera Universitaria Pisana, Pisa, Italy
| | - Chiara Molinelli
- IRCCS Ospedale Policlinico San Martino, U.O.S.D. Breast Unit, Genova, Italy
| | - Agnese Fabbri
- Medical Oncology Unit, Belcolle Hospital, Viterbo, Italy
| | - Emanuela Ferraro
- Division of Early Drug Development for Innovative Therapies, IEO, European Institute of Oncology IRCCS, Milan, Italy
| | - Dario Trapani
- Division of Early Drug Development for Innovative Therapies, IEO, European Institute of Oncology IRCCS, Milan, Italy
| | - Andrea Milani
- Multidisciplinary Oncology Outpatient Clinic, Candiolo Cancer Institute, FPO-IRCCS, Turin, Italy
| | - Elisa Agostinetto
- Medical Oncology and Hematology Unit, Humanitas Clinical and Research Center - IRCCS, Rozzano, Milan, Italy
| | - Ottavia Bernocchi
- Department of Medical, Surgery and Health Sciences, University of Trieste, Trieste, Italy
| | - Giovanna Catania
- Division of Medical Oncology, IRCCS Regina Elena National Cancer Institute, Rome, Italy
| | | | - Michela Palleschi
- Department of Medical Oncology, IRCCS Istituto Romagnolo per lo Studio dei Tumori "Dino Amadori" - IRST, Meldola, Italy
| | - Anna Moretti
- Department of Oncology, ASST Fatebenefratelli Sacco - PO Fatebenefratelli, Milan, Italy
| | - Debora Basile
- Department of Medical Oncology, IRCCS Centro di Riferimento Oncologico di Aviano (CRO), Aviano, Italy
| | - Marika Cinausero
- Department of Oncology, ASUFC University Hospital of Udine, Udine, Italy
| | - Arta Ajazi
- IFOM, the FIRC Institute of Molecular Oncology, Milan, Italy
| | - Lorenzo Castagnoli
- Molecular Targeting Unit, Department of Research, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Salvatore Lo Vullo
- Unit of Clinical Epidemiology and Trial Organization, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Lorenzo Gerratana
- Department of Medical Oncology, IRCCS Centro di Riferimento Oncologico di Aviano (CRO), Aviano, Italy.,Department of Medicine, University of Udine, Udine, Italy
| | - Fabio Puglisi
- Department of Medical Oncology, IRCCS Centro di Riferimento Oncologico di Aviano (CRO), Aviano, Italy.,Department of Medicine, University of Udine, Udine, Italy
| | - Nicla La Verde
- Department of Oncology, ASST Fatebenefratelli Sacco - PO Luigi Sacco, Milan, Italy
| | - Grazia Arpino
- Department of Clinical Medicine and Surgery, University of Naples Federico II, Naples, Italy
| | - Andrea Rocca
- Department of Medical Oncology, IRCCS Istituto Romagnolo per lo Studio dei Tumori "Dino Amadori" - IRST, Meldola, Italy
| | | | - Rebecca Pedersini
- Department of Medical and Surgical Specialties, Radiological Sciences, and Public Health, Medical Oncology, University of Brescia at ASST Spedali Civili, Brescia, Italy
| | - Alessandra Fabi
- Division of Medical Oncology, IRCCS Regina Elena National Cancer Institute, Rome, Italy
| | - Daniele Generali
- Department of Medical, Surgery and Health Sciences, University of Trieste, Trieste, Italy.,Breast Cancer Unit & Translational Research Unit, ASST Cremona, Cremona, Italy
| | - Agnese Losurdo
- Medical Oncology and Hematology Unit, Humanitas Clinical and Research Center - IRCCS, Rozzano, Milan, Italy
| | - Filippo Montemurro
- Multidisciplinary Oncology Outpatient Clinic, Candiolo Cancer Institute, FPO-IRCCS, Turin, Italy
| | - Giuseppe Curigliano
- Division of Early Drug Development for Innovative Therapies, IEO, European Institute of Oncology IRCCS, Milan, Italy.,Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
| | - Lucia Del Mastro
- IRCCS Ospedale Policlinico San Martino, U.O.S.D. Breast Unit, Genova, Italy.,Dipartimento di Medicina Interna e Specialità Mediche (DiMI), School of Medicine, University of Genova, Genova, Italy
| | - Andrea Michelotti
- UO Oncologia Medica 2, Ospedale S. Chiara, Dipartimento di Oncologia, Dei Trapianti e Delle Nuove Tecnologie, Azienda Ospedaliera Universitaria Pisana, Pisa, Italy
| | - Enrico Cortesi
- Department of Medico-Surgical Sciences and Translational Medicine, "Sapienza" University of Rome, Rome, Italy
| | - Valentina Guarneri
- Medical Oncology 2, Veneto Institute of Oncology IOV - IRCCS, Padua, Italy.,Department of Surgery, Oncology and Gastroenterology, University of Padova, Padua, Italy
| | - Giancarlo Pruneri
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy.,Department of Diagnostic Pathology and Laboratory Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Luigi Mariani
- Unit of Clinical Epidemiology and Trial Organization, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Filippo de Braud
- Department of Medical Oncology, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.,Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
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17
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Abstract
Cells metabolize nutrients for biosynthetic and bioenergetic needs to fuel growth and proliferation. The uptake of nutrients from the environment and their intracellular metabolism is a highly controlled process that involves cross talk between growth signaling and metabolic pathways. Despite constant fluctuations in nutrient availability and environmental signals, normal cells restore metabolic homeostasis to maintain cellular functions and prevent disease. A central signaling molecule that integrates growth with metabolism is the mechanistic target of rapamycin (mTOR). mTOR is a protein kinase that responds to levels of nutrients and growth signals. mTOR forms two protein complexes, mTORC1, which is sensitive to rapamycin, and mTORC2, which is not directly inhibited by this drug. Rapamycin has facilitated the discovery of the various functions of mTORC1 in metabolism. Genetic models that disrupt either mTORC1 or mTORC2 have expanded our knowledge of their cellular, tissue, as well as systemic functions in metabolism. Nevertheless, our knowledge of the regulation and functions of mTORC2, particularly in metabolism, has lagged behind. Since mTOR is an important target for cancer, aging, and other metabolism-related pathologies, understanding the distinct and overlapping regulation and functions of the two mTOR complexes is vital for the development of more effective therapeutic strategies. This review discusses the key discoveries and recent findings on the regulation and metabolic functions of the mTOR complexes. We highlight findings from cancer models but also discuss other examples of the mTOR-mediated metabolic reprogramming occurring in stem and immune cells, type 2 diabetes/obesity, neurodegenerative disorders, and aging.
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Affiliation(s)
- Angelia Szwed
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey
| | - Eugene Kim
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey
| | - Estela Jacinto
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey
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18
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Mateus T, Martins F, Nunes A, Herdeiro MT, Rebelo S. Metabolic Alterations in Myotonic Dystrophy Type 1 and Their Correlation with Lipin. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18041794. [PMID: 33673200 PMCID: PMC7918590 DOI: 10.3390/ijerph18041794] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/06/2021] [Accepted: 02/08/2021] [Indexed: 12/14/2022]
Abstract
Myotonic dystrophy type 1 (DM1) is an autosomal dominant hereditary and multisystemic disease, characterized by progressive distal muscle weakness and myotonia. Despite huge efforts, the pathophysiological mechanisms underlying DM1 remain elusive. In this review, the metabolic alterations observed in patients with DM1 and their connection with lipin proteins are discussed. We start by briefly describing the epidemiology, the physiopathological and systemic features of DM1. The molecular mechanisms proposed for DM1 are explored and summarized. An overview of metabolic syndrome, dyslipidemia, and the summary of metabolic alterations observed in patients with DM1 are presented. Patients with DM1 present clinical evidence of metabolic alterations, namely increased levels of triacylglycerol and low-density lipoprotein, increased insulin and glucose levels, increased abdominal obesity, and low levels of high-density lipoprotein. These metabolic alterations may be associated with lipins, which are phosphatidate phosphatase enzymes that regulates the triacylglycerol levels, phospholipids, lipid signaling pathways, and are transcriptional co-activators. Furthermore, lipins are also important for autophagy, inflammasome activation and lipoproteins synthesis. We demonstrate the association of lipin with the metabolic alterations in patients with DM1, which supports further clinical studies and a proper exploration of lipin proteins as therapeutic targets for metabolic syndrome, which is important for controlling many diseases including DM1.
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Affiliation(s)
| | | | | | | | - Sandra Rebelo
- Correspondence: ; Tel.: +351-924-406-306; Fax: +351-234-372-587
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19
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Song L, Liu Z, Hu HH, Yang Y, Li TY, Lin ZZ, Ye J, Chen J, Huang X, Liu DT, Zhou J, Shi Y, Zhao H, Xie C, Chen L, Song E, Lin SY, Lin SC. Proto-oncogene Src links lipogenesis via lipin-1 to breast cancer malignancy. Nat Commun 2020; 11:5842. [PMID: 33203880 PMCID: PMC7672079 DOI: 10.1038/s41467-020-19694-w] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 09/21/2020] [Indexed: 02/06/2023] Open
Abstract
Increased lipogenesis has been linked to an increased cancer risk and poor prognosis; however, the underlying mechanisms remain obscure. Here we show that phosphatidic acid phosphatase (PAP) lipin-1, which generates diglyceride precursors necessary for the synthesis of glycerolipids, interacts with and is a direct substrate of the Src proto-oncogenic tyrosine kinase. Obesity-associated microenvironmental factors and other Src-activating growth factors, including the epidermal growth factor, activate Src and promote Src-mediated lipin-1 phosphorylation on Tyr398, Tyr413 and Tyr795 residues. The tyrosine phosphorylation of lipin-1 markedly increases its PAP activity, accelerating the synthesis of glycerophospholipids and triglyceride. Alteration of the three tyrosine residues to phenylalanine (3YF-lipin-1) disables lipin-1 from mediating Src-enhanced glycerolipid synthesis, cell proliferation and xenograft growth. Re-expression of 3YF-lipin-1 in PyVT;Lpin1-/- mice fails to promote progression and metastasis of mammary tumours. Human breast tumours exhibit increased p-Tyr-lipin-1 levels compared to the adjacent tissues. Importantly, statistical analyses show that levels of p-Tyr-lipin-1 correlate with tumour sizes, lymph node metastasis, time to recurrence and survival of the patients. These results illustrate a direct lipogenesis-promoting role of the pro-oncogenic Src, providing a mechanistic link between obesity-associated mitogenic signaling and breast cancer malignancy.
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Affiliation(s)
- Lintao Song
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, 361102, Fujian, China
| | - Zhihua Liu
- Center of Intestinal Barrier and Fecal Microbiota Transplantation, The Fifth Affiliated Hospital of Guangzhou Medical University, 510700, Guangdong, China
| | - Hui-Hui Hu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, 361102, Fujian, China
| | - Ying Yang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, 361102, Fujian, China
| | - Terytty Yang Li
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, 361102, Fujian, China
| | - Zhi-Zhong Lin
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, 361102, Fujian, China
| | - Jing Ye
- Department of Pathology, Xijing Hospital, Fourth Military Medical University, 710000, Shaanxi, China
| | - Jianing Chen
- Breast Tumor Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 510120, Guangzhou, China
| | - Xi Huang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, 361102, Fujian, China
| | - Dong-Tai Liu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, 361102, Fujian, China
| | - Jing Zhou
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, 361102, Fujian, China
| | - Yiran Shi
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, 361102, Fujian, China
| | - Hao Zhao
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, 361102, Fujian, China
| | - Changchuan Xie
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, 361102, Fujian, China
| | - Lanfen Chen
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, 361102, Fujian, China
| | - Erwei Song
- Breast Tumor Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 510120, Guangzhou, China
| | - Shu-Yong Lin
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, 361102, Fujian, China
| | - Sheng-Cai Lin
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, 361102, Fujian, China.
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20
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The relationship between the mTOR signaling pathway and ovarian aging in peak-phase and late-phase laying hens. Poult Sci 2020; 100:334-347. [PMID: 33357698 PMCID: PMC7772700 DOI: 10.1016/j.psj.2020.10.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 08/21/2020] [Accepted: 10/06/2020] [Indexed: 11/23/2022] Open
Abstract
The molecular mechanisms underlying reproductive aging in avian species are poorly understood. Previous studies have shown the importance of mechanistic target of rapamycin (mTOR) signaling pathway in aging. In this study, we investigated the relationship between the mTOR signaling pathway and ovarian aging in the peak phase and late phase of egg production in laying hens. The egg production rate and egg quality were tracked for 5 consecutive weeks in 30-week-old and 70-week-old Dawu Jinfeng hens (N = 30/group). During the peak phase (week 35) and late phase (week 75), antioxidant and immune indicators were detected by enzyme-linked immunosorbent assay, and mTOR signaling-related genes (CLIP-170, GRB10, LIPIN-1, ATG1, 4E-BP1, S6K, PKC, RHO, and SGK1) were detected in the follicles by quantitative reverse transcription-PCR technology. The protein expression of key genes (mTOR, PKC, 4EBP1) was evaluated by Western blot analysis. The egg production rate and the antioxidant indexes superoxide dismutase and glutathione peroxidase and the levels of total antioxidant capacity and immunoglobulins (IgM and IgG) were significantly higher at week 35 than those at week 75 (P < 0.01), while malondialdehyde levels were significantly lower (P < 0.01). At week 75, there were fewer follicles in the different stages of development than were detected at week 35. The number of white follicles (large and small) and primary follicles were significantly higher at week 75 than those detected at week 35 (P < 0.01). The mRNA expression of avTOR, CLIP-170, GRB10, LIPIN-1, 4E-BP1, S6K, RHO, and SGK genes in small white follicles (SWF), large white follicles (LWF), F3, F1, and ovary at week 75 was lower than that in the hens at week 35 (P < 0.05). The mRNA expression in small yellow follicle (SYF) was significantly higher than that at week 35 (P < 0.05), while the mRNA expression of ULK1 in SWF, LWF, F3, F1, and ovary at week 75 was higher than that of hens at week 35 (P<0.01), and SYF was lower (P < 0.05). Treatment of chicken granulosa cells with the mTOR agonist MHY1485 significantly enhanced granulocyte proliferation (P < 0.01) and inhibited apoptosis (P < 0.01) and significantly increased avTOR, S6K, 4E-BP1, and PKC gene expression (P < 0.01). The protein expression levels of mTOR, S6K, p-mTOR, and p-S6K were consistent with mRNA expression levels. The mTOR activity is age-specific, and a compensatory enhancement of the mTOR signaling cascade can regulate ovarian follicular development in aged laying hens.
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21
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Lutkewitte AJ, Finck BN. Regulation of Signaling and Metabolism by Lipin-mediated Phosphatidic Acid Phosphohydrolase Activity. Biomolecules 2020; 10:E1386. [PMID: 33003344 PMCID: PMC7600782 DOI: 10.3390/biom10101386] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 09/23/2020] [Accepted: 09/24/2020] [Indexed: 12/15/2022] Open
Abstract
Phosphatidic acid (PA) is a glycerophospholipid intermediate in the triglyceride synthesis pathway that has incredibly important structural functions as a component of cell membranes and dynamic effects on intracellular and intercellular signaling pathways. Although there are many pathways to synthesize and degrade PA, a family of PA phosphohydrolases (lipin family proteins) that generate diacylglycerol constitute the primary pathway for PA incorporation into triglycerides. Previously, it was believed that the pool of PA used to synthesize triglyceride was distinct, compartmentalized, and did not widely intersect with signaling pathways. However, we now know that modulating the activity of lipin 1 has profound effects on signaling in a variety of cell types. Indeed, in most tissues except adipose tissue, lipin-mediated PA phosphohydrolase activity is far from limiting for normal rates of triglyceride synthesis, but rather impacts critical signaling cascades that control cellular homeostasis. In this review, we will discuss how lipin-mediated control of PA concentrations regulates metabolism and signaling in mammalian organisms.
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Affiliation(s)
| | - Brian N. Finck
- Center for Human Nutrition, Division of Geriatrics and Nutritional Sciences, Department of Medicine, Washington University School of Medicine, Euclid Avenue, Campus Box 8031, St. Louis, MO 63110, USA;
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22
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Takahara T, Amemiya Y, Sugiyama R, Maki M, Shibata H. Amino acid-dependent control of mTORC1 signaling: a variety of regulatory modes. J Biomed Sci 2020; 27:87. [PMID: 32799865 PMCID: PMC7429791 DOI: 10.1186/s12929-020-00679-2] [Citation(s) in RCA: 119] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 07/30/2020] [Indexed: 01/10/2023] Open
Abstract
The mechanistic target of rapamycin complex 1 (mTORC1) is an essential regulator of cell growth and metabolism through the modulation of protein and lipid synthesis, lysosome biogenesis, and autophagy. The activity of mTORC1 is dynamically regulated by several environmental cues, including amino acid availability, growth factors, energy levels, and stresses, to coordinate cellular status with environmental conditions. Dysregulation of mTORC1 activity is closely associated with various diseases, including diabetes, cancer, and neurodegenerative disorders. The discovery of Rag GTPases has greatly expanded our understanding of the regulation of mTORC1 activity by amino acids, especially leucine and arginine. In addition to Rag GTPases, other factors that also contribute to the modulation of mTORC1 activity have been identified. In this review, we discuss the mechanisms of regulation of mTORC1 activity by particular amino acids.
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Affiliation(s)
- Terunao Takahara
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601, Japan.
| | - Yuna Amemiya
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601, Japan
| | - Risa Sugiyama
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601, Japan
| | - Masatoshi Maki
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601, Japan
| | - Hideki Shibata
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601, Japan
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23
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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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24
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Crystal structure of a lipin/Pah phosphatidic acid phosphatase. Nat Commun 2020; 11:1309. [PMID: 32161260 PMCID: PMC7066176 DOI: 10.1038/s41467-020-15124-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Accepted: 02/20/2020] [Indexed: 12/12/2022] Open
Abstract
Lipin/Pah phosphatidic acid phosphatases (PAPs) generate diacylglycerol to regulate triglyceride synthesis and cellular signaling. Inactivating mutations cause rhabdomyolysis, autoinflammatory disease, and aberrant fat storage. Disease-mutations cluster within the conserved N-Lip and C-Lip regions that are separated by 500-residues in humans. To understand how the N-Lip and C-Lip combine for PAP function, we determined crystal structures of Tetrahymena thermophila Pah2 (Tt Pah2) that directly fuses the N-Lip and C-Lip. Tt Pah2 adopts a two-domain architecture where the N-Lip combines with part of the C-Lip to form an immunoglobulin-like domain and the remaining C-Lip forms a HAD-like catalytic domain. An N-Lip C-Lip fusion of mouse lipin-2 is catalytically active, which suggests mammalian lipins function with the same domain architecture as Tt Pah2. HDX-MS identifies an N-terminal amphipathic helix essential for membrane association. Disease-mutations disrupt catalysis or destabilize the protein fold. This illustrates mechanisms for lipin/Pah PAP function, membrane association, and lipin-related pathologies. Lipin/Pah phosphatidic acid phosphatases generate diacylglycerol to regulate triglyceride synthesis and cellular signaling. Here authors determine structures of Tetrahymena thermophila Pah2 and identify an N-terminal amphipathic helix essential for membrane association.
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25
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MacVicar T, Ohba Y, Nolte H, Mayer FC, Tatsuta T, Sprenger HG, Lindner B, Zhao Y, Li J, Bruns C, Krüger M, Habich M, Riemer J, Schwarzer R, Pasparakis M, Henschke S, Brüning JC, Zamboni N, Langer T. Lipid signalling drives proteolytic rewiring of mitochondria by YME1L. Nature 2019; 575:361-365. [PMID: 31695197 DOI: 10.1038/s41586-019-1738-6] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 09/19/2019] [Indexed: 01/18/2023]
Abstract
Reprogramming of mitochondria provides cells with the metabolic flexibility required to adapt to various developmental transitions such as stem cell activation or immune cell reprogramming, and to respond to environmental challenges such as those encountered under hypoxic conditions or during tumorigenesis1-3. Here we show that the i-AAA protease YME1L rewires the proteome of pre-existing mitochondria in response to hypoxia or nutrient starvation. Inhibition of mTORC1 induces a lipid signalling cascade via the phosphatidic acid phosphatase LIPIN1, which decreases phosphatidylethanolamine levels in mitochondrial membranes and promotes proteolysis. YME1L degrades mitochondrial protein translocases, lipid transfer proteins and metabolic enzymes to acutely limit mitochondrial biogenesis and support cell growth. YME1L-mediated mitochondrial reshaping supports the growth of pancreatic ductal adenocarcinoma (PDAC) cells as spheroids or xenografts. Similar changes to the mitochondrial proteome occur in the tumour tissues of patients with PDAC, suggesting that YME1L is relevant to the pathophysiology of these tumours. Our results identify the mTORC1-LIPIN1-YME1L axis as a post-translational regulator of mitochondrial proteostasis at the interface between metabolism and mitochondrial dynamics.
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Affiliation(s)
- Thomas MacVicar
- Max-Planck-Institute for Biology of Ageing, Cologne, Germany
| | - Yohsuke Ohba
- Max-Planck-Institute for Biology of Ageing, Cologne, Germany
| | - Hendrik Nolte
- Max-Planck-Institute for Biology of Ageing, Cologne, Germany.,Institute of Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | | | - Takashi Tatsuta
- Max-Planck-Institute for Biology of Ageing, Cologne, Germany
| | - Hans-Georg Sprenger
- Max-Planck-Institute for Biology of Ageing, Cologne, Germany.,Institute of Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Barbara Lindner
- Institute of Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Yue Zhao
- Department of General, Visceral and Cancer Surgery, University Hospital of Cologne, Cologne, Germany
| | - Jiahui Li
- Department of General, Visceral and Cancer Surgery, University Hospital of Cologne, Cologne, Germany
| | - Christiane Bruns
- Department of General, Visceral and Cancer Surgery, University Hospital of Cologne, Cologne, Germany
| | - Marcus Krüger
- Institute of Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Center for Molecular Medicine, University of Cologne, Cologne, Germany
| | - Markus Habich
- Institute for Biochemistry, University of Cologne, Cologne, Germany
| | - Jan Riemer
- Institute for Biochemistry, University of Cologne, Cologne, Germany
| | - Robin Schwarzer
- Institute of Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Manolis Pasparakis
- Max-Planck-Institute for Biology of Ageing, Cologne, Germany.,Institute of Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Center for Molecular Medicine, University of Cologne, Cologne, Germany
| | - Sinika Henschke
- Max-Planck-Institute for Metabolism Research, Cologne, Germany
| | - Jens C Brüning
- Center for Molecular Medicine, University of Cologne, Cologne, Germany.,Max-Planck-Institute for Metabolism Research, Cologne, Germany.,Center for Endocrinology, Diabetes and Preventive Medicine (CEPD), University Hospital of Cologne, Cologne, Germany
| | - Nicola Zamboni
- Molecular Systems Biology, ETH Zürich, Zürich, Switzerland
| | - Thomas Langer
- Max-Planck-Institute for Biology of Ageing, Cologne, Germany. .,Institute of Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany. .,Center for Molecular Medicine, University of Cologne, Cologne, Germany.
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26
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Hassaninasab A, Hsieh LS, Su WM, Han GS, Carman GM. Yck1 casein kinase I regulates the activity and phosphorylation of Pah1 phosphatidate phosphatase from Saccharomyces cerevisiae. J Biol Chem 2019; 294:18256-18268. [PMID: 31645435 DOI: 10.1074/jbc.ra119.011314] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 10/18/2019] [Indexed: 11/06/2022] Open
Abstract
The PAH1-encoded phosphatidate phosphatase in Saccharomyces cerevisiae plays a major role in triacylglycerol synthesis and the control of phospholipid synthesis. For its catalytic function on the nuclear/endoplasmic reticulum membrane, Pah1 translocates to the membrane through its phosphorylation/dephosphorylation. Pah1 phosphorylation on multiple serine/threonine residues is complex and catalyzed by diverse protein kinases. In this work, we demonstrate that Pah1 is phosphorylated by the YCK1-encoded casein kinase I (CKI), regulating Pah1 catalytic activity and phosphorylation. Phosphoamino acid analysis coupled with phosphopeptide mapping of the CKI-phosphorylated Pah1 indicated that it is phosphorylated mainly on multiple serine residues. Using site-directed mutagenesis and phosphorylation analysis of Pah1, we identified eight serine residues (i.e. Ser-114, Ser-475, Ser-511, Ser-602, Ser-677, Ser-705, Ser-748, and Ser-774) as the target sites of CKI. Of these residues, Ser-475 and Ser-511 were specific for CKI, whereas the others were shared by casein kinase II (Ser-705), Cdc28-cyclin B (Ser-602), Pho85-Pho80 (Ser-114, Ser-602, and Ser-748), protein kinase A (Ser-667 and Ser-774), and protein kinase C (Ser-677). CKI-mediated phosphorylation of Pah1 stimulated both its phosphatidate phosphatase activity and its subsequent phosphorylation by casein kinase II. However, the CKI-mediated phosphorylation of Pah1 strongly inhibited its subsequent phosphorylation by Pho85-Pho80, protein kinase A, and protein kinase C. In a reciprocal analysis, Pah1 phosphorylation by Pho85-Pho80 inhibited subsequent phosphorylation by CKI. CKI-mediated Pah1 phosphorylation was also inhibited by a peptide containing the Pah1 residues 506-517, including the kinase-specific Ser-511 residue. These findings advance our understanding of how Pah1 catalytic activity and phosphorylation are regulated by multiple protein kinases.
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Affiliation(s)
- Azam Hassaninasab
- Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - Lu-Sheng Hsieh
- Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - Wen-Min Su
- Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - Gil-Soo Han
- Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901
| | - George M Carman
- Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901.
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27
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Mollica V, Di Nunno V, Gatto L, Santoni M, Cimadamore A, Cheng L, Lopez-Beltran A, Montironi R, Pisconti S, Battelli N, Massari F. Novel Therapeutic Approaches and Targets Currently Under Evaluation for Renal Cell Carcinoma: Waiting for the Revolution. Clin Drug Investig 2019; 39:503-519. [PMID: 30937824 DOI: 10.1007/s40261-019-00773-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Management of metastatic renal cell carcinoma has drastically changed in the last few years, witnessing the advent of more and more target therapies and, recently, of immune-checkpoint inhibitors. On the other hand, the adjuvant setting still lacks a clear beneficial treatment. Medical treatment still remains a compelling challenge. A large number of clinical trials is ongoing with the aim to identify new therapeutic approaches to expand the options in our repertoire. Several strategies are under investigation in renal cell carcinoma (RCC). These include new targeted agents and combinations of target therapy and immunotherapy. Programmed death receptor-1 (PD-1), programmed death receptor ligand 1 (PD-L1) and cytotoxic T-lymphocyte antigen 4 (CTLA4) are just part of the intricate network that regulates our immune response to cancer cells. Co-stimulators, such as glucocorticoid-induced TNFR-related protein (GITR) and tumor necrosis factor receptor superfamily, member 4 (OX40), and co-repressors, example.g. T cell immunoglobulin and mucin domain 3 (TIM-3) and lymphocyte-activation gene 3 (LAG-3), also take part. As knowledge of the functioning of the immune system grows, so do these pathways to target with new drugs. This review is an overview of the current state of the clinical research, providing a report of ongoing Phase I, II and III clinical trials for localized and metastatic RCC, including novel target therapies, novel immunotherapy agents and new combinations strategies.
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Affiliation(s)
- Veronica Mollica
- Division of Oncology, S.Orsola-Malpighi Hospital, Bologna, Italy
| | | | - Lidia Gatto
- Oncology Unit, SG Moscati Hospital of Taranto, Taranto, Italy
| | | | - Alessia Cimadamore
- Section of Pathological Anatomy, United Hospital, School of Medicine, Polytechnic University of the Marche Region, Ancona, Italy
| | - Liang Cheng
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, USA
| | - Antonio Lopez-Beltran
- Department of Pathology and Surgery, Faculty of Medicine, Cordoba University, Cordoba, Spain
| | - Rodolfo Montironi
- Section of Pathological Anatomy, United Hospital, School of Medicine, Polytechnic University of the Marche Region, Ancona, Italy
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28
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Toward a genome-based treatment landscape for renal cell carcinoma. Crit Rev Oncol Hematol 2019; 142:141-152. [PMID: 31401421 DOI: 10.1016/j.critrevonc.2019.07.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 07/03/2019] [Accepted: 07/29/2019] [Indexed: 02/08/2023] Open
Abstract
Knowledge about molecular mechanisms driving development and progression of renal cell carcinoma has been elucidated by different studies. In few years we discovered a large difference between genomic landscapes of clear cell and non-clear cell carcinoma. Moreover, tumor heterogeneity and different acquisition of gene mutations during tumor progression are issues of particular interest. In this review we focalized our attention on principal genomic alterations identified among RCC subtypes. Acquired gene mutations may be an adaptive response to several external pressure including metabolic, treatment, genomic and immune-related external pressure. Thus we correlated and discussed principal genomic alterations adopted by tumor to escape from each external pressures. The aim of the present work is to summarize current knowledge about genomic alterations in RCC with special interest of treatment strategies tailored on the basis of disease mutations assessment.
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29
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Pan Q, Qin T, Gao Y, Li S, Li D, Peng M, Zhai H, Xu G. Hepatic mTOR-AKT2-Insig2 signaling pathway contributes to the improvement of hepatic steatosis after Roux-en-Y Gastric Bypass in mice. Biochim Biophys Acta Mol Basis Dis 2019; 1865:525-534. [DOI: 10.1016/j.bbadis.2018.12.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 11/26/2018] [Accepted: 12/12/2018] [Indexed: 12/18/2022]
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30
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Tian T, Li X, Zhang J. mTOR Signaling in Cancer and mTOR Inhibitors in Solid Tumor Targeting Therapy. Int J Mol Sci 2019; 20:ijms20030755. [PMID: 30754640 PMCID: PMC6387042 DOI: 10.3390/ijms20030755] [Citation(s) in RCA: 372] [Impact Index Per Article: 74.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 01/28/2019] [Accepted: 02/01/2019] [Indexed: 12/12/2022] Open
Abstract
The mammalian or mechanistic target of rapamycin (mTOR) pathway plays a crucial role in regulation of cell survival, metabolism, growth and protein synthesis in response to upstream signals in both normal physiological and pathological conditions, especially in cancer. Aberrant mTOR signaling resulting from genetic alterations from different levels of the signal cascade is commonly observed in various types of cancers. Upon hyperactivation, mTOR signaling promotes cell proliferation and metabolism that contribute to tumor initiation and progression. In addition, mTOR also negatively regulates autophagy via different ways. We discuss mTOR signaling and its key upstream and downstream factors, the specific genetic changes in the mTOR pathway and the inhibitors of mTOR applied as therapeutic strategies in eight solid tumors. Although monotherapy and combination therapy with mTOR inhibitors have been extensively applied in preclinical and clinical trials in various cancer types, innovative therapies with better efficacy and less drug resistance are still in great need, and new biomarkers and deep sequencing technologies will facilitate these mTOR targeting drugs benefit the cancer patients in personalized therapy.
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Affiliation(s)
- Tian Tian
- College of Life Science and Bioengineering, Beijing Jiaotong University, Beijing 100044, China.
| | - Xiaoyi Li
- College of Life Science and Bioengineering, Beijing Jiaotong University, Beijing 100044, China.
| | - Jinhua Zhang
- College of Life Science and Bioengineering, Beijing Jiaotong University, Beijing 100044, China.
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31
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Okuno H, Okuzono H, Hayase A, Kumagai F, Tanii S, Hino N, Okada Y, Tachibana K, Doi T, Ishimoto K. Lipin-1 is a novel substrate of protein phosphatase PGAM5. Biochem Biophys Res Commun 2019; 509:886-891. [PMID: 30642635 DOI: 10.1016/j.bbrc.2019.01.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Accepted: 01/06/2019] [Indexed: 10/27/2022]
Abstract
Lipin-1 has multiple functions that regulate lipid and energy metabolism according to its subcellular localization. The subcellular localization of Lipin-1 is determined by kinase-dependent phosphorylation; however, the phosphatase that dephosphorylates and inactivates Lipin-1 has remained elusive. Using an immunoprecipitation and LC-MS/MS approach we have identified phosphoglycerate mutase family member 5 (PGAM5), a serine/threonine specific protein phosphatase, as a regulator of Lipin-1 activity. Treatment of human hepatocellular carcinoma cells with carbonyl cyanide m-chlorophenyl hydrazone (CCCP), which activates endogenous PGAM5, promoted dephosphorylation and nuclear accumulation of Lipin-1. Our findings further elucidate the molecular mechanisms that regulate Lipin-1.
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Affiliation(s)
- Hiroko Okuno
- Laboratory of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Haruna Okuzono
- Laboratory of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Ayaka Hayase
- Laboratory of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Fumiko Kumagai
- Laboratory of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Shohei Tanii
- Laboratory of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Nobumasa Hino
- Laboratory of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yoshiaki Okada
- Laboratory of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Keisuke Tachibana
- Laboratory of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Takefumi Doi
- Laboratory of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | - Kenji Ishimoto
- Laboratory of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka, 565-0871, Japan.
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32
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Hennessy M, Granade ME, Hassaninasab A, Wang D, Kwiatek JM, Han GS, Harris TE, Carman GM. Casein kinase II-mediated phosphorylation of lipin 1β phosphatidate phosphatase at Ser-285 and Ser-287 regulates its interaction with 14-3-3β protein. J Biol Chem 2019; 294:2365-2374. [PMID: 30617183 DOI: 10.1074/jbc.ra118.007246] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 01/04/2019] [Indexed: 12/20/2022] Open
Abstract
The mammalian lipin 1 phosphatidate phosphatase is a key regulatory enzyme in lipid metabolism. By catalyzing phosphatidate dephosphorylation, which produces diacylglycerol, the enzyme plays a major role in the synthesis of triacylglycerol and membrane phospholipids. The importance of lipin 1 to lipid metabolism is exemplified by cellular defects and lipid-based diseases associated with its loss or overexpression. Phosphorylation of lipin 1 governs whether it is associated with the cytoplasm apart from its substrate or with the endoplasmic reticulum membrane where its enzyme reaction occurs. Lipin 1β is phosphorylated on multiple sites, but less than 10% of them are ascribed to a specific protein kinase. Here, we demonstrate that lipin 1β is a bona fide substrate for casein kinase II (CKII), a protein kinase that is essential to viability and cell cycle progression. Phosphoamino acid analysis and phosphopeptide mapping revealed that lipin 1β is phosphorylated by CKII on multiple serine and threonine residues, with the former being major sites. Mutational analysis of lipin 1β and its peptides indicated that Ser-285 and Ser-287 are both phosphorylated by CKII. Substitutions of Ser-285 and Ser-287 with nonphosphorylatable alanine attenuated the interaction of lipin 1β with 14-3-3β protein, a regulatory hub that facilitates the cytoplasmic localization of phosphorylated lipin 1. These findings advance our understanding of how phosphorylation of lipin 1β phosphatidate phosphatase regulates its interaction with 14-3-3β protein and intracellular localization and uncover a mechanism by which CKII regulates cellular physiology.
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Affiliation(s)
- Meagan Hennessy
- From the Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901 and
| | - Mitchell E Granade
- the Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Azam Hassaninasab
- From the Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901 and
| | - Dana Wang
- the Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Joanna M Kwiatek
- From the Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901 and
| | - Gil-Soo Han
- From the Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901 and
| | - Thurl E Harris
- the Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - George M Carman
- From the Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, New Jersey 08901 and
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33
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Bouillet B, Buffier P, Smati S, Archambeaud F, Cariou B, Vergès B. Expert opinion on the metabolic complications of mTOR inhibitors. ANNALES D'ENDOCRINOLOGIE 2018; 79:583-590. [PMID: 30144939 DOI: 10.1016/j.ando.2018.07.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Using mTOR inhibitors (mTORi) as anticancer drugs led to hyperglycemia (12-50%) and hyperlipidemia (7-73%) in phase-III trials. These high rates require adapted treatment in cancer patients. Before initiating mTORi treatment, lipid profile screening should be systematic, with fasting glucose assay in non-diabetic patients and HbA1C in diabetic patients. After initiation, lipid profile monitoring should be systematic, with fasting glucose assay in non-diabetic patients, every 2 weeks for the first month and then monthly. The HbA1C target is≤8%, before and after treatment initiation in known diabetic patients and in case of onset of diabetes under mTORi. LDL-cholesterol targets should be adapted to general health status and cardiovascular and oncologic prognosis. If treatment is indicated, pravastatin should be prescribed in first line; atorvastatin and simvastatin are contraindicated. Fenofibrate should be prescribed for hypertriglyceridemia>5g/l resisting dietary measures adapted to oncologic status. In non-controllable hypertriglyceridemia exceeding 10g/l, mTORi treatment should be interrupted and specialist opinion should be sought.
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Affiliation(s)
- Benjamin Bouillet
- Service d'endocrinologie, diabétologie, maladies métaboliques, CHU de Dijon, 2, boulevard du Maréchal-de-Lattre, BP 77908, 21000 Dijon, France; Unité Inserm, LNC-UMR 1231, université de Bourgogne, Dijon, France.
| | - Perrine Buffier
- Service d'endocrinologie, diabétologie, maladies métaboliques, CHU de Dijon, 2, boulevard du Maréchal-de-Lattre, BP 77908, 21000 Dijon, France
| | - Sarra Smati
- Clinique d'endocrinologie, Institut du Thorax, CHU de Nantes, Nantes, France
| | | | - Bertrand Cariou
- Clinique d'endocrinologie, Institut du Thorax, CHU de Nantes, Nantes, France
| | - Bruno Vergès
- Service d'endocrinologie, diabétologie, maladies métaboliques, CHU de Dijon, 2, boulevard du Maréchal-de-Lattre, BP 77908, 21000 Dijon, France; Unité Inserm, LNC-UMR 1231, université de Bourgogne, Dijon, France
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34
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Dawoody Nejad L, Serricchio M, Jelk J, Hemphill A, Bütikofer P. TbLpn, a key enzyme in lipid droplet formation and phospholipid metabolism, is essential for mitochondrial integrity and growth of Trypanosoma brucei. Mol Microbiol 2018; 109:105-120. [PMID: 29679486 DOI: 10.1111/mmi.13976] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/19/2018] [Indexed: 01/02/2023]
Abstract
Mammalian phosphatidic acid phosphatases, also called lipins, show high amino acid sequence identity to Saccharomyces cerevisiae Pah1p and catalyze the dephosphorylation of phosphatidic acid (PA) to diacylglycerol. Both the substrate and product of the reaction are key precursors for the synthesis of phospholipids and triacylglycerol (TAG). We now show that expression of the Trypanosoma brucei lipin homolog TbLpn is essential for parasite survival in culture. Inducible down-regulation of TbLpn in T. brucei procyclic forms increased cellular PA content, decreased the numbers of lipid droplets, reduced TAG steady-state levels and inhibited in vivo [3 H]TAG formation after labeling trypanosomes with [3 H]glycerol. In addition, fluorescence and transmission electron microscopy revealed that depletion of TbLpn caused major alterations in mitochondrial morphology and function, i.e., the appearance of distorted mitochondrial matrix, and reduced ATP production via oxidative phosphorylation. Effects of lipin depletion on mitochondrial integrity have previously not been reported. N- and C-terminally tagged forms of TbLpn were localized in the cytosol.
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Affiliation(s)
- Ladan Dawoody Nejad
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Mauro Serricchio
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
| | - Jennifer Jelk
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
| | - Andrew Hemphill
- Institute of Parasitology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Peter Bütikofer
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
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35
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Rahman MA, Mostofa MG, Ushimaru T. The Nem1/Spo7-Pah1/lipin axis is required for autophagy induction after TORC1 inactivation. FEBS J 2018; 285:1840-1860. [PMID: 29604183 DOI: 10.1111/febs.14448] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 02/01/2018] [Accepted: 03/26/2018] [Indexed: 02/06/2023]
Abstract
Autophagy is a process that requires intense membrane remodeling and consumption. The nutrient-responsive TORC1 (target of rapamycin complex 1) kinase regulates autophagy. However, how TORC1 controls autophagy via lipid/membrane biogenesis is unknown. TORC1 regulates the function of yeast phosphatidate phosphatase lipin Pah1 via the Nem1/Spo7 phosphatase complex. Here, we show that the Nem1/Spo7-Pah1 axis is required for autophagy induction after TORC1 inactivation and survival during starvation. Furthermore, this axis was critical for nucleophagy (both micronucleophagy and macronucleophagy) and was required for proper localization of micronucleophagy factor Nvj1 and macronucleophagy receptor Atg39. This study indicated that the Nem1/Spo7-Pah1 axis controlled by TORC1 is a critical branch for autophagy induction in nutrient starvation conditions.
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Affiliation(s)
| | - Md Golam Mostofa
- Graduate School of Science and Technology, Shizuoka University, Japan
| | - Takashi Ushimaru
- Graduate School of Science and Technology, Shizuoka University, Japan.,Department of Science, Graduate School of Integrated Science and Technology, Shizuoka University, Japan
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36
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Lehmann M. Endocrine and physiological regulation of neutral fat storage in Drosophila. Mol Cell Endocrinol 2018; 461:165-177. [PMID: 28893568 PMCID: PMC5756521 DOI: 10.1016/j.mce.2017.09.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 09/06/2017] [Accepted: 09/08/2017] [Indexed: 12/20/2022]
Abstract
After having revolutionized our understanding of the mechanisms of animal development, Drosophila melanogaster has more recently emerged as an equally valid genetic model in the field of animal metabolism. An increasing number of studies have revealed that many signaling pathways that control metabolism in mammals, including pathways controlled by nutrients (insulin, TOR), steroid hormone, glucagon, and hedgehog, are functionally conserved between mammals and Drosophila. In fact, genetic screens and analyses in Drosophila have identified new players and filled in gaps in the signaling networks that control metabolism. This review focuses on data that show how these networks control the formation and breakdown of triacylglycerol energy stores in the fat tissue of Drosophila.
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Affiliation(s)
- Michael Lehmann
- Department of Biological Sciences, SCEN 601, 1 University of Arkansas, Fayetteville, AR 72701, USA.
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37
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Singh P, Subbian S. Harnessing the mTOR Pathway for Tuberculosis Treatment. Front Microbiol 2018; 9:70. [PMID: 29441052 PMCID: PMC5797605 DOI: 10.3389/fmicb.2018.00070] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 01/11/2018] [Indexed: 01/23/2023] Open
Abstract
Tuberculosis (TB) remains as one of the leading killer infectious diseases of humans. At present, the standard therapeutic regimen to treat TB comprised of multiple antibiotics administered for a minimum of six months. Although these drugs are useful in controlling TB burden globally, they have not eliminated the disease. In addition, the lengthy duration of treatment with multiple drugs contributes to patient non-compliance that can result in the development of drug resistant strains (MDR and XDR) of Mycobacterium tuberculosis (Mtb), the causative agent of TB. Therefore, new and improved therapeutic strategies are urgently needed for effective control of TB worldwide. The intracellular survival of Mtb is regarded as a cumulative effect of the host immune response and the bacterial ability to resist or subvert this response. When the host innate defensive system is manipulated by Mtb for its survival and dissemination, the host develops disease conditions that are hard to overcome. The host intrinsic factors also contributes to the poor efficacy of anti-mycobacterial drugs and to the emergence of drug resistance. Hence, strengthening the immune repertoire involved in combating Mtb through host-directed therapeutics (HDT) can be one of the approaches for effective bacterial killing and clearance of infection/disease. Recently, more scientific research has been focused toward HDT strategies that empowers host cells for effective killing of Mtb, reduce the duration of treatment and/or alleviates the development of MDR/XDR, since Mtb cannot develop resistance against a drug that targets the host cell function. Autophagy is a conserved cellular process critical for maintaining cellular integrity and function. Autophagy is regulated by multiple pathways that are either dependent or independent of mTOR (mechanistic target of rapamycin; a.k.a. mammalian target of rapamycin), a master regulatory molecules that impacts several cellular functions. In this review, we summarize the role of autophagy in Mtb pathogenesis, the mTOR pathway and, modulating the mTOR pathway with inhibitors as potential adjunctive HDT, in combination with standard anti-TB antibiotics, to improve the outcome of current TB treatment.
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Affiliation(s)
- Pooja Singh
- Public Health Research Institute at New Jersey Medical School, Rutgers Biomedical and Health Sciences Rutgers, The State University of New Jersey, Newark, NJ, United States
| | - Selvakumar Subbian
- Public Health Research Institute at New Jersey Medical School, Rutgers Biomedical and Health Sciences Rutgers, The State University of New Jersey, Newark, NJ, United States
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38
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mTOR Cross-Talk in Cancer and Potential for Combination Therapy. Cancers (Basel) 2018; 10:cancers10010023. [PMID: 29351204 PMCID: PMC5789373 DOI: 10.3390/cancers10010023] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 01/15/2018] [Accepted: 01/16/2018] [Indexed: 12/20/2022] Open
Abstract
The mammalian Target of Rapamycin (mTOR) pathway plays an essential role in sensing and integrating a variety of exogenous cues to regulate cellular growth and metabolism, in both physiological and pathological conditions. mTOR functions through two functionally and structurally distinct multi-component complexes, mTORC1 and mTORC2, which interact with each other and with several elements of other signaling pathways. In the past few years, many new insights into mTOR function and regulation have been gained and extensive genetic and pharmacological studies in mice have enhanced our understanding of how mTOR dysfunction contributes to several diseases, including cancer. Single-agent mTOR targeting, mostly using rapalogs, has so far met limited clinical success; however, due to the extensive cross-talk between mTOR and other pathways, combined approaches are the most promising avenues to improve clinical efficacy of available therapeutics and overcome drug resistance. This review provides a brief and up-to-date narrative on the regulation of mTOR function, the relative contributions of mTORC1 and mTORC2 complexes to cancer development and progression, and prospects for mTOR inhibition as a therapeutic strategy.
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39
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Antikainen H, Driscoll M, Haspel G, Dobrowolski R. TOR-mediated regulation of metabolism in aging. Aging Cell 2017; 16:1219-1233. [PMID: 28971552 PMCID: PMC5676073 DOI: 10.1111/acel.12689] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2017] [Indexed: 01/06/2023] Open
Abstract
Cellular metabolism is regulated by the mTOR kinase, a key component of the molecular nutrient sensor pathway that plays a central role in cellular survival and aging. The mTOR pathway promotes protein and lipid synthesis and inhibits autophagy, a process known for its contribution to longevity in several model organisms. The nutrient‐sensing pathway is regulated at the lysosomal membrane by a number of proteins for which deficiency triggers widespread aging phenotypes in tested animal models. In response to environmental cues, this recently discovered lysosomal nutrient‐sensing complex regulates autophagy transcriptionally through conserved factors, such as the transcription factors TFEB and FOXO, associated with lifespan extension. This key metabolic pathway strongly depends on nucleocytoplasmic compartmentalization, a cellular phenomenon gradually lost during aging. In this review, we discuss the current progress in understanding the contribution of mTOR‐regulating factors to autophagy and longevity. Furthermore, we review research on the regulation of metabolism conducted in multiple aging models, including Caenorhabditis elegans, Drosophila and mouse, and human iPSCs. We suggest that conserved molecular pathways have the strongest potential for the development of new avenues for treatment of age‐related diseases.
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Affiliation(s)
- Henri Antikainen
- Federated Department of Biological Sciences New Jersey Institute of Technology Rutgers University Newark NJ 07102 USA
| | - Monica Driscoll
- Department of Molecular Biology and Biochemistry Rutgers University Piscataway NJ 08854 USA
| | - Gal Haspel
- Federated Department of Biological Sciences New Jersey Institute of Technology Rutgers University Newark NJ 07102 USA
| | - Radek Dobrowolski
- Federated Department of Biological Sciences New Jersey Institute of Technology Rutgers University Newark NJ 07102 USA
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40
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Jacquemyn J, Cascalho A, Goodchild RE. The ins and outs of endoplasmic reticulum-controlled lipid biosynthesis. EMBO Rep 2017; 18:1905-1921. [PMID: 29074503 DOI: 10.15252/embr.201643426] [Citation(s) in RCA: 151] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 08/18/2017] [Accepted: 09/18/2017] [Indexed: 12/21/2022] Open
Abstract
Endoplasmic reticulum (ER)-localized enzymes synthesize the vast majority of cellular lipids. The ER therefore has a major influence on cellular lipid biomass and balances the production of different lipid categories, classes, and species. Signals from outside and inside the cell are directed to ER-localized enzymes, and lipid enzyme activities are defined by the integration of internal, homeostatic, and external information. This allows ER-localized lipid synthesis to provide the cell with membrane lipids for growth, proliferation, and differentiation-based changes in morphology and structure, and to maintain membrane homeostasis across the cell. ER enzymes also respond to physiological signals to drive carbohydrates and nutritionally derived lipids into energy-storing triglycerides. In this review, we highlight some key regulatory mechanisms that control ER-localized enzyme activities in animal cells. We also discuss how they act in concert to maintain cellular lipid homeostasis, as well as how their dysregulation contributes to human disease.
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Affiliation(s)
- Julie Jacquemyn
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium.,Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Ana Cascalho
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium.,Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Rose E Goodchild
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium .,Department of Neurosciences, KU Leuven, Leuven, Belgium
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41
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Boroda S, Takkellapati S, Lawrence RT, Entwisle SW, Pearson JM, Granade ME, Mullins GR, Eaton JM, Villén J, Harris TE. The phosphatidic acid-binding, polybasic domain is responsible for the differences in the phosphoregulation of lipins 1 and 3. J Biol Chem 2017; 292:20481-20493. [PMID: 28982975 DOI: 10.1074/jbc.m117.786574] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 09/23/2017] [Indexed: 11/06/2022] Open
Abstract
Lipins 1, 2, and 3 are Mg2+-dependent phosphatidic acid phosphatases and catalyze the penultimate step of triacylglycerol synthesis. We have previously investigated the biochemistry of lipins 1 and 2 and shown that di-anionic phosphatidic acid (PA) augments their activity and lipid binding and that lipin 1 activity is negatively regulated by phosphorylation. In the present study, we show that phosphorylation does not affect the catalytic activity of lipin 3 or its ability to associate with PA in vitro The lipin proteins each contain a conserved polybasic domain (PBD) composed of nine lysine and arginine residues located between the conserved N- and C-terminal domains. In lipin 1, the PBD is the site of PA binding and sensing of the PA electrostatic charge. The specific arrangement and number of the lysines and arginines of the PBD vary among the lipins. We show that the different PBDs of lipins 1 and 3 are responsible for the presence of phosphoregulation on the former but not the latter enzyme. To do so, we generated lipin 1 that contained the PBD of lipin 3 and vice versa. The lipin 1 enzyme with the lipin 3 PBD lost its ability to be regulated by phosphorylation but remained downstream of phosphorylation by mammalian target of rapamycin. Conversely, the presence of the lipin 1 PBD in lipin 3 subjected the enzyme to negative intramolecular control by phosphorylation. These results indicate a mechanism for the observed differences in lipin phosphoregulation in vitro.
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Affiliation(s)
- Salome Boroda
- From the Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908 and
| | - Sankeerth Takkellapati
- From the Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908 and
| | - Robert T Lawrence
- the Department of Genome Sciences, University of Washington, Seattle, Washington 98195
| | - Samuel W Entwisle
- the Department of Genome Sciences, University of Washington, Seattle, Washington 98195
| | - Jennifer M Pearson
- From the Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908 and
| | - Mitchell E Granade
- From the Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908 and
| | - Garrett R Mullins
- From the Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908 and
| | - James M Eaton
- From the Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908 and
| | - Judit Villén
- the Department of Genome Sciences, University of Washington, Seattle, Washington 98195
| | - Thurl E Harris
- From the Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908 and
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42
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Wang H, Airola MV, Reue K. How lipid droplets "TAG" along: Glycerolipid synthetic enzymes and lipid storage. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:1131-1145. [PMID: 28642195 PMCID: PMC5688854 DOI: 10.1016/j.bbalip.2017.06.010] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 06/15/2017] [Accepted: 06/15/2017] [Indexed: 02/06/2023]
Abstract
Triacylglycerols (TAG) serve as the predominant form of energy storage in mammalian cells, and TAG synthesis influences conditions such as obesity, fatty liver, and insulin resistance. In most tissues, the glycerol 3-phosphate pathway enzymes are responsible for TAG synthesis, and the regulation and function of these enzymes is therefore important for metabolic homeostasis. Here we review the sites and regulation of glycerol-3-phosphate acyltransferase (GPAT), acylglycerol-3-phosphate acyltransferase (AGPAT), lipin phosphatidic acid phosphatase (PAP), and diacylglycerol acyltransferase (DGAT) enzyme action. We highlight the critical roles that these enzymes play in human health by reviewing Mendelian disorders that result from mutation in the corresponding genes. We also summarize the valuable insights that genetically engineered mouse models have provided into the cellular and physiological roles of GPATs, AGPATs, lipins and DGATs. Finally, we comment on the status and feasibility of therapeutic approaches to metabolic disease that target enzymes of the glycerol 3-phosphate pathway. This article is part of a Special Issue entitled: Recent Advances in Lipid Droplet Biology edited by Rosalind Coleman and Matthijs Hesselink.
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Affiliation(s)
- Huan Wang
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Michael V Airola
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, United States
| | - Karen Reue
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States; Molecular Biology Institute, University of California, Los Angeles, CA, United States.
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43
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Xie Z, Zhang J, Ma S, Huang X, Huang Y. Effect of Chinese herbal medicine treatment on plasma lipid profile and hepatic lipid metabolism in Hetian broiler. Poult Sci 2017; 96:1918-1924. [DOI: 10.3382/ps/pew456] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 12/04/2016] [Indexed: 12/27/2022] Open
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44
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Lee PL, Jung SM, Guertin DA. The Complex Roles of Mechanistic Target of Rapamycin in Adipocytes and Beyond. Trends Endocrinol Metab 2017; 28:319-339. [PMID: 28237819 PMCID: PMC5682923 DOI: 10.1016/j.tem.2017.01.004] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 01/20/2017] [Accepted: 01/23/2017] [Indexed: 01/01/2023]
Abstract
Having healthy adipose tissue is essential for metabolic fitness. This is clear from the obesity epidemic, which is unveiling a myriad of comorbidities associated with excess adipose tissue including type 2 diabetes, cardiovascular disease, and cancer. Lipodystrophy also causes insulin resistance, emphasizing the importance of having a balanced amount of fat. In cells, the mechanistic target of rapamycin (mTOR) complexes 1 and 2 (mTORC1 and mTORC2, respectively) link nutrient and hormonal signaling with metabolism, and recent studies are shedding new light on their in vivo roles in adipocytes. In this review, we discuss how recent advances in adipose tissue and mTOR biology are converging to reveal new mechanisms that maintain healthy adipose tissue, and discuss ongoing mysteries of mTOR signaling, particularly for the less understood complex mTORC2.
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Affiliation(s)
- Peter L Lee
- Program in Molecular Medicine, University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA 01605, USA
| | - Su Myung Jung
- Program in Molecular Medicine, University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA 01605, USA
| | - David A Guertin
- Program in Molecular Medicine, University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA 01605, USA.
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45
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Zhang P, Reue K. Lipin proteins and glycerolipid metabolism: Roles at the ER membrane and beyond. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:1583-1595. [PMID: 28411173 DOI: 10.1016/j.bbamem.2017.04.007] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 03/29/2017] [Accepted: 04/09/2017] [Indexed: 01/09/2023]
Abstract
The regulation of glycerolipid biosynthesis is critical for homeostasis of cellular lipid stores and membranes. Here we review the role of lipin phosphatidic acid phosphatase enzymes in glycerolipid synthesis. Lipin proteins are unique among glycerolipid biosynthetic enzymes in their ability to transit among cellular membranes, rather than remain membrane tethered. We focus on the mechanisms that underlie lipin protein interactions with membranes and the versatile roles of lipins in several organelles, including the endoplasmic reticulum, mitochondria, endolysosomes, lipid droplets, and nucleus. We also review the corresponding physiological roles of lipins, which have been uncovered by the study of genetic lipin deficiencies. We propose that the growing body of knowledge concerning the biochemical and cellular activities of lipin proteins will be valuable for understanding the physiological functions of lipin proteins in health and disease. This article is part of a Special Issue entitled: Membrane Lipid Therapy: Drugs Targeting Biomembranes edited by Pablo V. Escribá.
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Affiliation(s)
- Peixiang Zhang
- Human Genetics, David Geffen School of Medicine at UCLA, University of California, Los Angeles, United States
| | - Karen Reue
- Human Genetics, David Geffen School of Medicine at UCLA, University of California, Los Angeles, United States; Molecular Biology Institute, University of California, Los Angeles, United States.
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46
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Suárez-Vega A, Gutiérrez-Gil B, Klopp C, Tosser-Klopp G, Arranz JJ. Variant discovery in the sheep milk transcriptome using RNA sequencing. BMC Genomics 2017; 18:170. [PMID: 28202015 PMCID: PMC5312585 DOI: 10.1186/s12864-017-3581-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 02/10/2017] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND The identification of genetic variation underlying desired phenotypes is one of the main challenges of current livestock genetic research. High-throughput transcriptome sequencing (RNA-Seq) offers new opportunities for the detection of transcriptome variants (SNPs and short indels) in different tissues and species. In this study, we used RNA-Seq on Milk Sheep Somatic Cells (MSCs) with the goal of characterizing the genetic variation within the coding regions of the milk transcriptome in Churra and Assaf sheep, two common dairy sheep breeds farmed in Spain. RESULTS A total of 216,637 variants were detected in the MSCs transcriptome of the eight ewes analyzed. Among them, a total of 57,795 variants were detected in the regions harboring Quantitative Trait Loci (QTL) for milk yield, protein percentage and fat percentage, of which 21.44% were novel variants. Among the total variants detected, 561 (2.52%) and 1,649 (7.42%) were predicted to produce high or moderate impact changes in the corresponding transcriptional unit, respectively. In the functional enrichment analysis of the genes positioned within selected QTL regions harboring novel relevant functional variants (high and moderate impact), the KEGG pathway with the highest enrichment was "protein processing in endoplasmic reticulum". Additionally, a total of 504 and 1,063 variants were identified in the genes encoding principal milk proteins and molecules involved in the lipid metabolism, respectively. Of these variants, 20 mutations were found to have putative relevant effects on the encoded proteins. CONCLUSIONS We present herein the first transcriptomic approach aimed at identifying genetic variants of the genes expressed in the lactating mammary gland of sheep. Through the transcriptome analysis of variability within regions harboring QTL for milk yield, protein percentage and fat percentage, we have found several pathways and genes that harbor mutations that could affect dairy production traits. Moreover, remarkable variants were also found in candidate genes coding for major milk proteins and proteins related to milk fat metabolism. Several of the SNPs found in this study could be included as suitable markers in genotyping platforms or custom SNP arrays to perform association analyses in commercial populations and apply genomic selection protocols in the dairy production industry.
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Affiliation(s)
- Aroa Suárez-Vega
- Departamento de Producción Animal, Facultad de Veterinaria, Universidad de León, Campus de Vegazana s/n, León, 24071, Spain
| | - Beatriz Gutiérrez-Gil
- Departamento de Producción Animal, Facultad de Veterinaria, Universidad de León, Campus de Vegazana s/n, León, 24071, Spain
| | - Christophe Klopp
- INRA, Plateforme bioinformatique Toulouse Midi-Pyrénées, UR875 Biométrie et Intelligence Artificielle, BP 52627, 31326, Castanet-Tolosan Cedex, France
| | | | - Juan José Arranz
- Departamento de Producción Animal, Facultad de Veterinaria, Universidad de León, Campus de Vegazana s/n, León, 24071, Spain.
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47
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Abstract
OBJECTIVE Epilepsy is a chronic neurological disease characterised with seizures. The aetiology of the most generalised epilepsies cannot be explicitly determined and the seizures are pronounced to be genetically determined by disturbances of receptors in central nervous system. Besides, neurotransmitter distributions or other metabolic problems are supposed to involve in epileptogenesis. Lack of adequate data about pharmacological agents that have antiepileptogenic effects point to need of research on this field. Thus, in this review, inflammatory aspects of epileptogenesis has been focussed via considering several concepts like role of immune system, blood-brain barrier and antibody involvement in epileptogenesis. METHODS We conducted an evidence-based review of the literatures in order to evaluate the possible participation of inflammatory processes to epileptogenesis and also, promising agents which are effective to these processes. We searched PubMed database up to November 2015 with no date restrictions. RESULTS In the present review, 163 appropriate articles were included. Obtained data suggests that inflammatory processes participate to epileptogenesis in several ways like affecting fibroblast growth factor-2 and tropomyosin receptor kinase B signalling pathways, detrimental proinflammatory pathways [such as the interleukin-1 beta (IL-1β)-interleukin-1 receptor type 1 (IL-1R1) system], mammalian target of rapamycin pathway, microglial activities, release of glial inflammatory proteins (such as macrophage inflammatory protein, interleukin 6, C-C motif ligand 2 and IL-1β), adhesion molecules that are suggested to function in signalling pathways between neurons and microglia and also linkage between these molecules and proinflammatory cytokines. CONCLUSION The literature research indicated that inflammation is a part of epileptogenesis. For this reason, further studies are necessary for assessing agents that will be effective in clinical use for therapeutic treatment of epileptogenesis.
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Kim JY, Kim G, Lim SC, Choi HS. LPIN1 promotes epithelial cell transformation and mammary tumourigenesis via enhancing insulin receptor substrate 1 stability. Carcinogenesis 2016; 37:1199-1209. [PMID: 27729374 DOI: 10.1093/carcin/bgw104] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 08/25/2016] [Accepted: 10/10/2016] [Indexed: 02/07/2023] Open
Abstract
LPIN1 is a protein that exhibits dual functions as a phosphatidic acid phosphatase enzyme in regulation of triglyceride and glycerophospholipid metabolism and a transcriptional coregulator. Through unknown tumour-promoting mechanism, LPIN1 frequently observed in various human cancer cell lines controls main cellular processes involved in cancer progression. Here, we demonstrate that LPIN1 enhances the tumour-promoting function of insulin receptor substrate 1 (IRS1) by controlling IRS1 stability. LPIN1 interacts with IRS1 in an insulin growth factor-1-dependent signalling pathway and inhibits its serine phosphorylation, and thereby eliminating ubiquitin-dependent degradation of IRS1 via proteasomal and lysosomal pathways. Consequently, LPIN1 overexpression increases IRS1 abundance and enhances IRS1's ability to induce epithelial cell proliferation and mammary tumourigenesis. By contrast, depletion or inhibition of LPIN1 in breast cancer cells leads to a decreased IRS1 level, which subsequently inhibits the RAF1-mediated signalling pathway and AP-1 activity. In the syngeneic 4T1 breast cancer model, LPIN1 overexpression increased tumour development, whereas inhibition of LPIN1 and IRS1 suppressed it. Consistent with these observations, LPIN1 levels were positively correlated with IRS1 expression in human breast cancer. Thus, our results indicate a mechanism by which IRS1 expression is increased in breast cancer, and LPIN1 may be a promising drug target for anticancer therapy.
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Affiliation(s)
| | | | - Sung-Chul Lim
- Department of Pathology, School of Medicine, Chosun University, 309 Philmundaero, Dong-gu, Gwangju 61452, Republic of Korea
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Granata S, Dalla Gassa A, Carraro A, Brunelli M, Stallone G, Lupo A, Zaza G. Sirolimus and Everolimus Pathway: Reviewing Candidate Genes Influencing Their Intracellular Effects. Int J Mol Sci 2016; 17:ijms17050735. [PMID: 27187382 PMCID: PMC4881557 DOI: 10.3390/ijms17050735] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 04/21/2016] [Accepted: 05/06/2016] [Indexed: 02/07/2023] Open
Abstract
Sirolimus (SRL) and everolimus (EVR) are mammalian targets of rapamycin inhibitors (mTOR-I) largely employed in renal transplantation and oncology as immunosuppressive/antiproliferative agents. SRL was the first mTOR-I produced by the bacterium Streptomyces hygroscopicus and approved for several medical purposes. EVR, derived from SRL, contains a 2-hydroxy-ethyl chain in the 40th position that makes the drug more hydrophilic than SRL and increases oral bioavailability. Their main mechanism of action is the inhibition of the mTOR complex 1 and the regulation of factors involved in a several crucial cellular functions including: protein synthesis, regulation of angiogenesis, lipid biosynthesis, mitochondrial biogenesis and function, cell cycle, and autophagy. Most of the proteins/enzymes belonging to the aforementioned biological processes are encoded by numerous and tightly regulated genes. However, at the moment, the polygenic influence on SRL/EVR cellular effects is still not completely defined, and its comprehension represents a key challenge for researchers. Therefore, to obtain a complete picture of the cellular network connected to SRL/EVR, we decided to review major evidences available in the literature regarding the genetic influence on mTOR-I biology/pharmacology and to build, for the first time, a useful and specific “SRL/EVR genes-focused pathway”, possibly employable as a starting point for future in-depth research projects.
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Affiliation(s)
- Simona Granata
- Renal Unit, Department of Medicine, University/Hospital of Verona, 37126 Verona, Italy.
| | | | - Amedeo Carraro
- Liver Transplant Unit, Department of General Surgery and Odontoiatrics, University/Hospital of Verona, 37126 Verona, Italy.
| | - Matteo Brunelli
- Department of Pathology and Diagnostics, University of Verona, Azienda Ospedaliera Universitaria Integrata, 37126 Verona, Italy.
| | - Giovanni Stallone
- Nephrology, Dialysis and Transplantation Unit, University of Foggia, 71122 Foggia, Italy.
| | - Antonio Lupo
- Renal Unit, Department of Medicine, University/Hospital of Verona, 37126 Verona, Italy.
| | - Gianluigi Zaza
- Renal Unit, Department of Medicine, University/Hospital of Verona, 37126 Verona, Italy.
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Sun L, Yu Y, Hu W, Min Q, Kang H, Li Y, Hong Y, Wang X, Hong Y. Ribosomal protein S6 kinase1 coordinates with TOR-Raptor2 to regulate thylakoid membrane biosynthesis in rice. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:639-49. [PMID: 27102613 DOI: 10.1016/j.bbalip.2016.04.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 03/16/2016] [Accepted: 04/15/2016] [Indexed: 01/01/2023]
Abstract
Ribosomal protein S6 kinase (S6K) functions as a key component in the target of rapamycin (TOR) pathway involved in multiple processes in eukaryotes. The role and regulation of TOR-S6K in lipid metabolism remained unknown in plants. Here we provide genetic and pharmacological evidence that TOR-Raptor2-S6K1 is important for thylakoid galactolipid biosynthesis and thylakoid grana modeling in rice (Oryza sativa L.). Genetic suppression of S6K1 caused pale yellow-green leaves, defective thylakoid grana architecture. S6K1 directly interacts with Raptor2, a core component in TOR signaling, and S6K1 activity is regulated by Raptor2 and TOR. Plants with suppressed Raptor2 expression or reduced TOR activity by inhibitors mimicked the S6K1-deficient phenotype. A significant reduction in galactolipid content was found in the s6k1, raptor2 mutant or TOR-inhibited plants, which was accompanied by decreased transcript levels of the set of genes such as lipid phosphate phosphatase α5 (LPPα5), MGDG synthase 1 (MGD1), and DGDG synthase 1 (DGD1) involved in galactolipid synthesis, compared to the control plants. Moreover, loss of LPPα5 exhibited a similar phenotype with pale yellow-green leaves. These results suggest that TOR-Raptor2-S6K1 is important for modulating thylakoid membrane lipid biosynthesis, homeostasis, thus enhancing thylakoid grana architecture and normal photosynthesis ability in rice.
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Affiliation(s)
- Linxiao Sun
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yonghua Yu
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Weiqin Hu
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Qiming Min
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Huiling Kang
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yilu Li
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yue Hong
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Xuemin Wang
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yueyun Hong
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
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