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Norris AC, Mansueto AJ, Jimenez M, Yazlovitskaya EM, Jain BK, Graham TR. Flipping the script: Advances in understanding how and why P4-ATPases flip lipid across membranes. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119700. [PMID: 38382846 DOI: 10.1016/j.bbamcr.2024.119700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 11/15/2023] [Accepted: 02/16/2024] [Indexed: 02/23/2024]
Abstract
Type IV P-type ATPases (P4-ATPases) are a family of transmembrane enzymes that translocate lipid substrates from the outer to the inner leaflet of biological membranes and thus create an asymmetrical distribution of lipids within membranes. On the cellular level, this asymmetry is essential for maintaining the integrity and functionality of biological membranes, creating platforms for signaling events and facilitating vesicular trafficking. On the organismal level, this asymmetry has been shown to be important in maintaining blood homeostasis, liver metabolism, neural development, and the immune response. Indeed, dysregulation of P4-ATPases has been linked to several diseases; including anemia, cholestasis, neurological disease, and several cancers. This review will discuss the evolutionary transition of P4-ATPases from cation pumps to lipid flippases, the new lipid substrates that have been discovered, the significant advances that have been achieved in recent years regarding the structural mechanisms underlying the recognition and flipping of specific lipids across biological membranes, and the consequences of P4-ATPase dysfunction on cellular and physiological functions. Additionally, we emphasize the requirement for additional research to comprehensively understand the involvement of flippases in cellular physiology and disease and to explore their potential as targets for therapeutics in treating a variety of illnesses. The discussion in this review will primarily focus on the budding yeast, C. elegans, and mammalian P4-ATPases.
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Affiliation(s)
- Adriana C Norris
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | | | - Mariana Jimenez
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | | | - Bhawik K Jain
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Todd R Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA.
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2
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Furuta Y, Zhou Z. How do necrotic cells expose phosphatidylserine to attract their predators—What’s unique and what’s in common with apoptotic cells. Front Cell Dev Biol 2023; 11:1170551. [PMID: 37091984 PMCID: PMC10113483 DOI: 10.3389/fcell.2023.1170551] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 03/27/2023] [Indexed: 04/09/2023] Open
Abstract
Phosphatidylserine (PS) is a lipid component of the plasma membrane. It is asymmetrically distributed to the inner leaflet in live cells. In cells undergoing apoptosis, phosphatidylserine is exposed to the outer surfaces. The exposed phosphatidylserine acts as an evolutionarily conserved “eat-me” signal that attracts neighboring engulfing cells in metazoan organisms, including the nematode Caenorhabditis elegans, the fruit fly Drosophila melanogaster, and mammals. During apoptosis, the exposure of phosphatidylserine to the outer surface of a cell is driven by the membrane scramblases and flippases, the activities of which are regulated by caspases. Cells undergoing necrosis, a kind of cell death frequently associated with cellular injuries and morphologically distinct from apoptosis, were initially believed to allow passive exposure of phosphatidylserine through membrane rupture. Later studies revealed that necrotic cells actively expose phosphatidylserine before any rupture occurs. A recent study in C. elegans further reported that the calcium ion (Ca2+) plays an essential role in promoting the exposure of phosphatidylserine on the surfaces of necrotic cells. These findings indicate that necrotic and apoptotic cells, which die through different molecular mechanisms, use common and unique mechanisms for promoting the exposure of the same “eat me” signal. This article will review the mechanisms regulating the exposure of phosphatidylserine on the surfaces of necrotic and apoptotic cells and highlight their similarities and differences.
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3
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Takasugi N, Komai M, Kaneshiro N, Ikeda A, Kamikubo Y, Uehara T. The Pursuit of the "Inside" of the Amyloid Hypothesis-Is C99 a Promising Therapeutic Target for Alzheimer's Disease? Cells 2023; 12:cells12030454. [PMID: 36766796 PMCID: PMC9914381 DOI: 10.3390/cells12030454] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 01/27/2023] [Accepted: 01/28/2023] [Indexed: 02/04/2023] Open
Abstract
Aducanumab, co-developed by Eisai (Japan) and Biogen (U.S.), has received Food and Drug Administration approval for treating Alzheimer's disease (AD). In addition, its successor antibody, lecanemab, has been approved. These antibodies target the aggregated form of the small peptide, amyloid-β (Aβ), which accumulates in the patient brain. The "amyloid hypothesis" based therapy that places the aggregation and toxicity of Aβ at the center of the etiology is about to be realized. However, the effects of immunotherapy are still limited, suggesting the need to reconsider this hypothesis. Aβ is produced from a type-I transmembrane protein, Aβ precursor protein (APP). One of the APP metabolites, the 99-amino acids C-terminal fragment (C99, also called βCTF), is a direct precursor of Aβ and accumulates in the AD patient's brain to demonstrate toxicity independent of Aβ. Conventional drug discovery strategies have focused on Aβ toxicity on the "outside" of the neuron, but C99 accumulation might explain the toxicity on the "inside" of the neuron, which was overlooked in the hypothesis. Furthermore, the common region of C99 and Aβ is a promising target for multifunctional AD drugs. This review aimed to outline the nature, metabolism, and impact of C99 on AD pathogenesis and discuss whether it could be a therapeutic target complementing the amyloid hypothesis.
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Affiliation(s)
- Nobumasa Takasugi
- Department of Medicinal Pharmacology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, 2-1-1 Hongo Bunkyo-ku, Tokyo 113-8421, Japan
- Correspondence:
| | - Masato Komai
- Department of Medicinal Pharmacology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan
| | - Nanaka Kaneshiro
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA 92521, USA
- Center for RNA Biology and Medicine, University of California, Riverside, CA 92521, USA
| | - Atsuya Ikeda
- Department of Medicinal Pharmacology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan
| | - Yuji Kamikubo
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, 2-1-1 Hongo Bunkyo-ku, Tokyo 113-8421, Japan
| | - Takashi Uehara
- Department of Medicinal Pharmacology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan
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Castillo-Quan JI, Steinbaugh MJ, Fernández-Cárdenas LP, Pohl NK, Wu Z, Zhu F, Moroz N, Teixeira V, Bland MS, Lehrbach NJ, Moronetti L, Teufl M, Blackwell TK. An antisteatosis response regulated by oleic acid through lipid droplet-mediated ERAD enhancement. SCIENCE ADVANCES 2023; 9:eadc8917. [PMID: 36598980 PMCID: PMC9812393 DOI: 10.1126/sciadv.adc8917] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 11/23/2022] [Indexed: 05/19/2023]
Abstract
Although excessive lipid accumulation is a hallmark of obesity-related pathologies, some lipids are beneficial. Oleic acid (OA), the most abundant monounsaturated fatty acid (FA), promotes health and longevity. Here, we show that OA benefits Caenorhabditis elegans by activating the endoplasmic reticulum (ER)-resident transcription factor SKN-1A (Nrf1/NFE2L1) in a lipid homeostasis response. SKN-1A/Nrf1 is cleared from the ER by the ER-associated degradation (ERAD) machinery and stabilized when proteasome activity is low and canonically maintains proteasome homeostasis. Unexpectedly, OA increases nuclear SKN-1A levels independently of proteasome activity, through lipid droplet-dependent enhancement of ERAD. In turn, SKN-1A reduces steatosis by reshaping the lipid metabolism transcriptome and mediates longevity from OA provided through endogenous accumulation, reduced H3K4 trimethylation, or dietary supplementation. Our findings reveal an unexpected mechanism of FA signal transduction, as well as a lipid homeostasis pathway that provides strategies for opposing steatosis and aging, and may mediate some benefits of the OA-rich Mediterranean diet.
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Affiliation(s)
- Jorge Iván Castillo-Quan
- Section on Islet Cell and Regenerative Biology, Research Division, Joslin Diabetes Center, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Harvard Stem Cell Institute, Harvard Medical School, Boston, MA, USA
| | - Michael J. Steinbaugh
- Section on Islet Cell and Regenerative Biology, Research Division, Joslin Diabetes Center, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Harvard Stem Cell Institute, Harvard Medical School, Boston, MA, USA
| | - Laura Paulette Fernández-Cárdenas
- Section on Islet Cell and Regenerative Biology, Research Division, Joslin Diabetes Center, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Harvard Stem Cell Institute, Harvard Medical School, Boston, MA, USA
| | - Nancy K. Pohl
- Section on Islet Cell and Regenerative Biology, Research Division, Joslin Diabetes Center, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Harvard Stem Cell Institute, Harvard Medical School, Boston, MA, USA
| | - Ziyun Wu
- Section on Islet Cell and Regenerative Biology, Research Division, Joslin Diabetes Center, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Harvard Stem Cell Institute, Harvard Medical School, Boston, MA, USA
| | - Feimei Zhu
- Section on Islet Cell and Regenerative Biology, Research Division, Joslin Diabetes Center, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Harvard Stem Cell Institute, Harvard Medical School, Boston, MA, USA
| | - Natalie Moroz
- Section on Islet Cell and Regenerative Biology, Research Division, Joslin Diabetes Center, Boston, MA, USA
- Biology Department, Emmanuel College, Boston, MA, USA
| | - Veronica Teixeira
- Section on Islet Cell and Regenerative Biology, Research Division, Joslin Diabetes Center, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Harvard Stem Cell Institute, Harvard Medical School, Boston, MA, USA
| | - Monet S. Bland
- Section on Islet Cell and Regenerative Biology, Research Division, Joslin Diabetes Center, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Harvard Stem Cell Institute, Harvard Medical School, Boston, MA, USA
| | - Nicolas J. Lehrbach
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA
| | - Lorenza Moronetti
- Section on Islet Cell and Regenerative Biology, Research Division, Joslin Diabetes Center, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Harvard Stem Cell Institute, Harvard Medical School, Boston, MA, USA
| | - Magdalena Teufl
- Section on Islet Cell and Regenerative Biology, Research Division, Joslin Diabetes Center, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Harvard Stem Cell Institute, Harvard Medical School, Boston, MA, USA
| | - T. Keith Blackwell
- Section on Islet Cell and Regenerative Biology, Research Division, Joslin Diabetes Center, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Harvard Stem Cell Institute, Harvard Medical School, Boston, MA, USA
- Corresponding author.
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5
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Wang Q, Zhu Y, Song B, Fu R, Zhou Y. The In Vivo Toxicity Assessments of Water-Dispersed Fluorescent Silicon Nanoparticles in Caenorhabditis elegans. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19074101. [PMID: 35409783 PMCID: PMC8998271 DOI: 10.3390/ijerph19074101] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 03/27/2022] [Accepted: 03/29/2022] [Indexed: 12/17/2022]
Abstract
Fluorescent silicon nanoparticles (SiNPs), resembling a typical zero-dimensional silicon nanomaterial, have shown great potential in a wide range of biological and biomedical applications. However, information regarding the toxicity of this material in live organisms is still very scarce. In this study, we utilized Caenorhabditis elegans (C. elegans), a simple but biologically and anatomically well-described model, as a platform to systematically investigate the in vivo toxicity of SiNPs in live organisms at the whole-animal, cellular, subcellular, and molecular levels. We calculated the effect of SiNPs on C. elegans body length (N ≥ 75), lifespan (N ≥ 30), reproductive capacity (N ≥ 10), endocytic sorting (N ≥ 20), endoplasmic reticulum (ER) stress (N ≥ 20), mitochondrial stress (N ≥ 20), oxidative stress (N ≥ 20), immune response (N ≥ 20), apoptosis (N ≥ 200), hypoxia response (N ≥ 200), metal detoxification (N ≥ 200), and aging (N ≥ 200). The studies showed that SiNPs had no significant effect on development, lifespan, or reproductive ability (p > 0.05), even when the worms were treated with a high concentration (e.g., 50 mg/mL) of SiNPs at all growth and development stages. Subcellular analysis of the SiNP-treated worms revealed that the intracellular processes of the C. elegans intestine were not disturbed by the presence of SiNPs (p > 0.05). Toxicity analyses at the molecular level also demonstrated that the SiNPs did not induce harmful or defensive cellular events, such as ER stress, mitochondria stress, or oxidative stress (p > 0.05). Together, these findings confirmed that the SiNPs are low in toxicity and biocompatible, supporting the suggestion that the material is an ideal fluorescent nanoprobe for wide-ranging biological and biomedical applications.
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Affiliation(s)
- Qin Wang
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences (IBMS), Soochow University, Suzhou 215123, China; (Q.W.); (Y.Z.); (R.F.)
| | - Yi Zhu
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences (IBMS), Soochow University, Suzhou 215123, China; (Q.W.); (Y.Z.); (R.F.)
| | - Bin Song
- Institute of Functional Nano & Soft Materials (FUNSOM) and Collaborative Innovation Center of Suzhou Nano Science and Technology, Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou 215123, China;
| | - Rong Fu
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences (IBMS), Soochow University, Suzhou 215123, China; (Q.W.); (Y.Z.); (R.F.)
| | - Yanfeng Zhou
- Institute of Functional Nano & Soft Materials (FUNSOM) and Collaborative Innovation Center of Suzhou Nano Science and Technology, Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou 215123, China;
- School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
- Correspondence:
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6
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Hasegawa J, Uchida Y, Mukai K, Lee S, Matsudaira T, Taguchi T. A Role of Phosphatidylserine in the Function of Recycling Endosomes. Front Cell Dev Biol 2022; 9:783857. [PMID: 35004683 PMCID: PMC8740049 DOI: 10.3389/fcell.2021.783857] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 11/29/2021] [Indexed: 11/13/2022] Open
Abstract
Cells internalize proteins and lipids in the plasma membrane (PM) and solutes in the extracellular space by endocytosis. The removal of PM by endocytosis is constantly balanced by the replenishment of proteins and lipids to PM through recycling pathway. Recycling endosomes (REs) are specific subsets of endosomes. Besides the established role of REs in recycling pathway, recent studies have revealed unanticipated roles of REs in membrane traffic and cell signalling. In this review, we highlight these emerging issues, with a particular focus on phosphatidylserine (PS), a phospholipid that is highly enriched in the cytosolic leaflet of RE membranes. We also discuss the pathogenesis of Hermansky Pudlak syndrome type 2 (HPS2) that arises from mutations in the AP3B1 gene, from the point of view of dysregulated RE functions.
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Affiliation(s)
- Junya Hasegawa
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Yasunori Uchida
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Kojiro Mukai
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Shoken Lee
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Tatsuyuki Matsudaira
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Tomohiko Taguchi
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
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7
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Brandt JN, Voss L, Rambo FM, Nicholson K, Thein JR, Fairchild L, Seabrook L, Lewis D, Guevara-Hernandez L, White ML, Sax L, Eichten V, Harper L, Hermann GJ. Asymmetric organelle positioning during epithelial polarization of C. elegans intestinal cells. Dev Biol 2022; 481:75-94. [PMID: 34597675 PMCID: PMC8665101 DOI: 10.1016/j.ydbio.2021.09.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 09/11/2021] [Accepted: 09/24/2021] [Indexed: 01/03/2023]
Abstract
While the epithelial cell cortex displays profound asymmetries in protein distribution and morphology along the apico-basal axis, the extent to which the cytoplasm is similarly polarized within epithelial cells remains relatively unexplored. We show that cytoplasmic organelles within C. elegans embryonic intestinal cells develop extensive apico-basal polarity at the time they establish cortical asymmetry. Nuclei and conventional endosomes, including early endosomes, late endosomes, and lysosomes, become polarized apically. Lysosome-related gut granules, yolk platelets, and lipid droplets become basally enriched. Removal of par-3 activity does not disrupt organelle positioning, indicating that cytoplasmic apico-basal asymmetry is independent of the PAR polarity pathway. Blocking the apical migration of nuclei leads to the apical positioning of gut granules and yolk platelets, whereas the asymmetric localization of conventional endosomes and lipid droplets is unaltered. This suggests that nuclear positioning organizes some, but not all, cytoplasmic asymmetries in this cell type. We show that gut granules become apically enriched when WHT-2 and WHT-7 function is disrupted, identifying a novel role for ABCG transporters in gut granule positioning during epithelial polarization. Analysis of WHT-2 and WHT-7 ATPase mutants is consistent with a WHT-2/WHT-7 heterodimer acting as a transporter in gut granule positioning. In wht-2(-) mutants, the polarized distribution of other organelles is not altered and gut granules do not take on characteristics of conventional endosomes that could have explained their apical mispositioning. During epithelial polarization wht-2(-) gut granules exhibit a loss of the Rab32/38 family member GLO-1 and ectopic expression of GLO-1 is sufficient to rescue the basal positioning of wht-2(-) and wht-7(-) gut granules. Furthermore, depletion of GLO-1 causes the mislocalization of the endolysosomal RAB-7 to gut granules and RAB-7 drives the apical mispositioning of gut granules when GLO-1, WHT-2, or WHT-7 function is disrupted. We suggest that ABC transporters residing on gut granules can regulate Rab dynamics to control organelle positioning during epithelial polarization.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | - Greg J. Hermann
- Corresponding author. Department of Biology, Lewis & Clark College, Portland, OR, USA, (G.J. Hermann)
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8
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Zhang H, Cheng Z, Li W, Hu J, Zhao L, Chen D, Gao J, Chen J, Yan Y, Lin L, Shi A. WTS-1/LATS regulates endocytic recycling by restraining F-actin assembly in a synergistic manner. J Cell Sci 2021; 134:273738. [PMID: 34817059 DOI: 10.1242/jcs.259085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 11/16/2021] [Indexed: 12/30/2022] Open
Abstract
The disruption of endosomal actin architecture negatively affects endocytic recycling. However, the underlying homeostatic mechanisms that regulate actin organization during recycling remain unclear. In this study, we identified a synergistic endosomal actin assembly restricting mechanism in C. elegans involving WTS-1, the homolog of LATS kinases, which is a core component of the Hippo pathway. WTS-1 resides on the sorting endosomes and colocalizes with the actin polymerization regulator PTRN-1 [the homolog of the calmodulin-regulated spectrin-associated proteins (CAMSAPs)]. We observed an increase in PTRN-1-labeled structures in WTS-1-deficient cells, indicating that WTS-1 can limit the endosomal localization of PTRN-1. Accordingly, the actin overaccumulation phenotype in WTS-1-depleted cells was mitigated by the associated PTRN-1 loss. We further demonstrated that recycling defects and actin overaccumulation in WTS-1-deficient cells were reduced by the overexpression of constitutively active UNC-60A(S3A) (a cofilin protein homolog), which aligns with the role of LATS as a positive regulator of cofilin activity. Altogether, our data confirmed previous findings, and we propose an additional model, that WTS-1 acts alongside the UNC-60A-mediated actin disassembly to restrict the assembly of endosomal F-actin by curbing PTRN-1 dwelling on endosomes, preserving recycling transport.
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Affiliation(s)
- Hanchong Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China
| | - Zihang Cheng
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China
| | - Wenbo Li
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China
| | - Jie Hu
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China
| | - Linyue Zhao
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China
| | - Dan Chen
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China
| | - Jinghu Gao
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China
| | - Juan Chen
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China.,Cell Architecture Research Center, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China
| | - Yanling Yan
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China.,Cell Architecture Research Center, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China
| | - Long Lin
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China.,Cell Architecture Research Center, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China
| | - Anbing Shi
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China.,Cell Architecture Research Center, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China
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9
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Nilsson L, Rahmani S, Tuck S. C. elegans TAT-6, a putative aminophospholipid translocase, is expressed in sujc cells in the hermaphrodite gonad. MICROPUBLICATION BIOLOGY 2021; 2021. [PMID: 34746684 PMCID: PMC8569451 DOI: 10.17912/micropub.biology.000495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 10/25/2021] [Accepted: 10/25/2021] [Indexed: 11/28/2022]
Abstract
In healthy eukaryotic cells, the two leaflets that make up plasma membranes are highly asymmetric with respect to the lipids they contain. In both unicellular eukaryotes and metazoans, the asymmetry in the distribution of aminophospholipids is maintained by P4-family transmembrane ATPases, which catalyze the movement of selected phospholipids from the outer leaflet to the inner. C. elegans has six P4-family ATPases, TAT-1 – TAT-6. TAT-1 – TAT-5 are expressed in many tissues and cells. Here we report that, in contrast, TAT-6 is much less broadly expressed and that, within the somatic gonad, expression of TAT-6 reporters is restricted to the spermathecal-uterine core cell (sujc) cells.
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10
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Lenoir G, D'Ambrosio JM, Dieudonné T, Čopič A. Transport Pathways That Contribute to the Cellular Distribution of Phosphatidylserine. Front Cell Dev Biol 2021; 9:737907. [PMID: 34540851 PMCID: PMC8440936 DOI: 10.3389/fcell.2021.737907] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 08/10/2021] [Indexed: 12/05/2022] Open
Abstract
Phosphatidylserine (PS) is a negatively charged phospholipid that displays a highly uneven distribution within cellular membranes, essential for establishment of cell polarity and other processes. In this review, we discuss how combined action of PS biosynthesis enzymes in the endoplasmic reticulum (ER), lipid transfer proteins (LTPs) acting within membrane contact sites (MCS) between the ER and other compartments, and lipid flippases and scramblases that mediate PS flip-flop between membrane leaflets controls the cellular distribution of PS. Enrichment of PS in specific compartments, in particular in the cytosolic leaflet of the plasma membrane (PM), requires input of energy, which can be supplied in the form of ATP or by phosphoinositides. Conversely, coupling between PS synthesis or degradation, PS flip-flop and PS transfer may enable PS transfer by passive flow. Such scenario is best documented by recent work on the formation of autophagosomes. The existence of lateral PS nanodomains, which is well-documented in the case of the PM and postulated for other compartments, can change the steepness or direction of PS gradients between compartments. Improvements in cellular imaging of lipids and membranes, lipidomic analysis of complex cellular samples, reconstitution of cellular lipid transport reactions and high-resolution structural data have greatly increased our understanding of cellular PS homeostasis. Our review also highlights how budding yeast has been instrumental for our understanding of the organization and transport of PS in cells.
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Affiliation(s)
- Guillaume Lenoir
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, Gif-sur-Yvette, France
| | - Juan Martín D'Ambrosio
- Centre de Recherche en Biologie Cellulaire de Montpellier (CRBM), Université de Montpellier, CNRS, Montpellier, France
| | - Thibaud Dieudonné
- Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic EMBL Partnership for Molecular Medicine, Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Alenka Čopič
- Centre de Recherche en Biologie Cellulaire de Montpellier (CRBM), Université de Montpellier, CNRS, Montpellier, France
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11
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Schmick M, Bastiaens PIH. Understanding Ras Spatial Cycles Through Reaction-Diffusion Simulations. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2021; 2262:199-215. [PMID: 33977478 DOI: 10.1007/978-1-0716-1190-6_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Reaction-diffusion simulations allow us to recapitulate experimentally observed behavior, e.g., from time series of fluorescent micrographs. This is essential to inform our intuitive understanding of the chemical and biophysical interaction of proteins in a cellular context as well as their role in reaction networks. This chapter aims to give a brief introduction to setting up reaction-diffusion simulations and applies these in silico techniques to take apart the spatial cycles that maintain Ras localization in the cell.
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Affiliation(s)
- Malte Schmick
- Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Philippe I H Bastiaens
- Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany. .,Faculty of Chemistry and Chemical Biology, TU Dortmund, Dortmund, Germany.
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12
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Perez MA, Watts JL. Worms, Fat, and Death: Caenorhabditis elegans Lipid Metabolites Regulate Cell Death. Metabolites 2021; 11:metabo11020125. [PMID: 33672292 PMCID: PMC7926963 DOI: 10.3390/metabo11020125] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 02/19/2021] [Accepted: 02/19/2021] [Indexed: 12/28/2022] Open
Abstract
Caenorhabditis elegans is well-known as the model organism used to elucidate the genetic pathways underlying the first described form of regulated cell death, apoptosis. Since then, C. elegans investigations have contributed to the further understanding of lipids in apoptosis, especially the roles of phosphatidylserines and phosphatidylinositols. More recently, studies in C. elegans have shown that dietary polyunsaturated fatty acids can induce the non-apoptotic, iron-dependent form of cell death, ferroptosis. In this review, we examine the roles of various lipids in specific aspects of regulated cell death, emphasizing recent work in C. elegans.
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13
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Redpath GMI, Betzler VM, Rossatti P, Rossy J. Membrane Heterogeneity Controls Cellular Endocytic Trafficking. Front Cell Dev Biol 2020; 8:757. [PMID: 32850860 PMCID: PMC7419583 DOI: 10.3389/fcell.2020.00757] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 07/20/2020] [Indexed: 12/21/2022] Open
Abstract
Endocytic trafficking relies on highly localized events in cell membranes. Endocytosis involves the gathering of protein (cargo/receptor) at distinct plasma membrane locations defined by specific lipid and protein compositions. Simultaneously, the molecular machinery that drives invagination and eventually scission of the endocytic vesicle assembles at the very same place on the inner leaflet of the membrane. It is membrane heterogeneity - the existence of specific lipid and protein domains in localized regions of membranes - that creates the distinct molecular identity required for an endocytic event to occur precisely when and where it is required rather than at some random location within the plasma membrane. Accumulating evidence leads us to believe that the trafficking fate of internalized proteins is sealed following endocytosis, as this distinct membrane identity is preserved through the endocytic pathway, upon fusion of endocytic vesicles with early and sorting endosomes. In fact, just like at the plasma membrane, multiple domains coexist at the surface of these endosomes, regulating local membrane tubulation, fission and sorting to recycling pathways or to the trans-Golgi network via late endosomes. From here, membrane heterogeneity ensures that fusion events between intracellular vesicles and larger compartments are spatially regulated to promote the transport of cargoes to their intracellular destination.
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Affiliation(s)
- Gregory M I Redpath
- Department of Biochemistry, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.,The ANZAC Research Institute, Concord Repatriation General Hospital, Concord, NSW, Australia
| | - Verena M Betzler
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland.,Biotechnology Institute Thurgau (BITg) at the University of Konstanz, Kreuzlingen, Switzerland
| | - Pascal Rossatti
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland.,Biotechnology Institute Thurgau (BITg) at the University of Konstanz, Kreuzlingen, Switzerland
| | - Jérémie Rossy
- Biotechnology Institute Thurgau (BITg) at the University of Konstanz, Kreuzlingen, Switzerland.,Department of Biology, University of Konstanz, Konstanz, Germany
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14
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Pan P, Xu L, Zhang H, Liu Y, Lu X, Chen G, Tang H, Wu J. A Review of Hematoma Components Clearance Mechanism After Subarachnoid Hemorrhage. Front Neurosci 2020; 14:685. [PMID: 32733194 PMCID: PMC7358443 DOI: 10.3389/fnins.2020.00685] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 06/04/2020] [Indexed: 12/18/2022] Open
Abstract
Subarachnoid hemorrhage (SAH) is a complicated clinical syndrome, which is caused by several kinds of cerebrovascular disorders, with high morbidity, disability and mortality rate. In recent years, several studies have shown that early brain injury (EBI) is an important factor leading to the poor prognosis of SAH. A major cause of EBI has been attributed that hematoma components invade into the brain parenchyma, resulting in neuronal cell death. Therefore, the clearance of hematoma components is essential in the clinical outcome of patients after SAH. Here, in the review, we provide a summary of the current known hematoma components clearance mechanisms and simultaneously propose a new hypothesis for hematoma components clearance.
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Affiliation(s)
- Pengjie Pan
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Li Xu
- Intensive Care Unit of Department of Anesthesiology, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Hongrong Zhang
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Yuan Liu
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Xiaocheng Lu
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Gang Chen
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Hailiang Tang
- Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, China
| | - Jiang Wu
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Suzhou, China
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15
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Petkovic M, Oses-Prieto J, Burlingame A, Jan LY, Jan YN. TMEM16K is an interorganelle regulator of endosomal sorting. Nat Commun 2020; 11:3298. [PMID: 32620747 PMCID: PMC7335067 DOI: 10.1038/s41467-020-17016-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 06/05/2020] [Indexed: 12/17/2022] Open
Abstract
Communication between organelles is essential for their cellular homeostasis. Neurodegeneration reflects the declining ability of neurons to maintain cellular homeostasis over a lifetime, where the endolysosomal pathway plays a prominent role by regulating protein and lipid sorting and degradation. Here we report that TMEM16K, an endoplasmic reticulum lipid scramblase causative for spinocerebellar ataxia (SCAR10), is an interorganelle regulator of the endolysosomal pathway. We identify endosomal transport as a major functional cluster of TMEM16K in proximity biotinylation proteomics analyses. TMEM16K forms contact sites with endosomes, reconstituting split-GFP with the small GTPase RAB7. Our study further implicates TMEM16K lipid scrambling activity in endosomal sorting at these sites. Loss of TMEM16K function led to impaired endosomal retrograde transport and neuromuscular function, one of the symptoms of SCAR10. Thus, TMEM16K-containing ER-endosome contact sites represent clinically relevant platforms for regulating endosomal sorting.
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Affiliation(s)
- Maja Petkovic
- Departments of Physiology, Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA, 94158, USA.
| | - Juan Oses-Prieto
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Alma Burlingame
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Lily Yeh Jan
- Departments of Physiology, Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA, 94158, USA
- Howard Hughes Medical Institute, University of California, San Francisco, CA, USA
| | - Yuh Nung Jan
- Departments of Physiology, Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA, 94158, USA.
- Howard Hughes Medical Institute, University of California, San Francisco, CA, USA.
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16
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The roles of the diversity of amphipathic lipids in shaping membranes by membrane-shaping proteins. Biochem Soc Trans 2020; 48:837-851. [PMID: 32597479 DOI: 10.1042/bst20190376] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 06/02/2020] [Accepted: 06/05/2020] [Indexed: 12/23/2022]
Abstract
Lipid compositions of cells differ according to cell types and intracellular organelles. Phospholipids are major cell membrane lipids and have hydrophilic head groups and hydrophobic fatty acid tails. The cellular lipid membrane without any protein adapts to spherical shapes, and protein binding to the membrane is thought to be required for shaping the membrane for various cellular events. Until recently, modulation of cellular lipid membranes was initially shown to be mediated by proteins recognizing lipid head groups, including the negatively charged ones of phosphatidylserine and phosphoinositides. Recent studies have shown that the abilities of membrane-deforming proteins are also regulated by the composition of fatty acid tails, which cause different degrees of packing defects. The binding of proteins to cellular lipid membranes is affected by the packing defects, presumably through modulation of their interactions with hydrophobic amino acid residues. Therefore, lipid composition can be characterized by both packing defects and charge density. The lipid composition regarding fatty acid tails affects membrane bending via the proteins with amphipathic helices, including those with the ArfGAP1 lipid packing sensor (ALPS) motif and via membrane-deforming proteins with structural folding, including those with the Bin-Amphiphysin-Rvs167 (BAR) domains. This review focuses on how the fatty acid tails, in combination with the head groups of phospholipids, affect protein-mediated membrane deformation.
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17
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Voss L, Foster OK, Harper L, Morris C, Lavoy S, Brandt JN, Peloza K, Handa S, Maxfield A, Harp M, King B, Eichten V, Rambo FM, Hermann GJ. An ABCG Transporter Functions in Rab Localization and Lysosome-Related Organelle Biogenesis in Caenorhabditis elegans. Genetics 2020; 214:419-445. [PMID: 31848222 PMCID: PMC7017009 DOI: 10.1534/genetics.119.302900] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 12/11/2019] [Indexed: 12/20/2022] Open
Abstract
ABC transporters couple ATP hydrolysis to the transport of substrates across cellular membranes. This protein superfamily has diverse activities resulting from differences in their cargo and subcellular localization. Our work investigates the role of the ABCG family member WHT-2 in the biogenesis of gut granules, a Caenorhabditis elegans lysosome-related organelle. In addition to being required for the accumulation of birefringent material within gut granules, WHT-2 is necessary for the localization of gut granule proteins when trafficking pathways to this organelle are partially disrupted. The role of WHT-2 in gut granule protein targeting is likely linked to its function in Rab GTPase localization. We show that WHT-2 promotes the gut granule association of the Rab32 family member GLO-1 and the endolysosomal RAB-7, identifying a novel function for an ABC transporter. WHT-2 localizes to gut granules where it could play a direct role in controlling Rab localization. Loss of CCZ-1 and GLO-3, which likely function as a guanine nucleotide exchange factor (GEF) for GLO-1, lead to similar disruption of GLO-1 localization. We show that CCZ-1, like GLO-3, is localized to gut granules. WHT-2 does not direct the gut granule association of the GLO-1 GEF and our results point to WHT-2 functioning differently than GLO-3 and CCZ-1 Point mutations in WHT-2 that inhibit its transport activity, but not its subcellular localization, lead to the loss of GLO-1 from gut granules, while other WHT-2 activities are not completely disrupted, suggesting that WHT-2 functions in organelle biogenesis through transport-dependent and transport-independent activities.
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Affiliation(s)
- Laura Voss
- Department of Biology, Lewis & Clark College, Portland, Oregon
| | - Olivia K Foster
- Department of Biology, Lewis & Clark College, Portland, Oregon
| | - Logan Harper
- Department of Biology, Lewis & Clark College, Portland, Oregon
| | - Caitlin Morris
- Department of Biology, Lewis & Clark College, Portland, Oregon
| | - Sierra Lavoy
- Department of Biology, Lewis & Clark College, Portland, Oregon
| | - James N Brandt
- Department of Biology, Lewis & Clark College, Portland, Oregon
| | - Kimberly Peloza
- Department of Biology, Lewis & Clark College, Portland, Oregon
| | - Simran Handa
- Department of Biology, Lewis & Clark College, Portland, Oregon
| | - Amanda Maxfield
- Department of Biology, Lewis & Clark College, Portland, Oregon
| | - Marie Harp
- Department of Biology, Lewis & Clark College, Portland, Oregon
| | - Brian King
- Department of Biology, Lewis & Clark College, Portland, Oregon
| | | | - Fiona M Rambo
- Department of Biology, Lewis & Clark College, Portland, Oregon
| | - Greg J Hermann
- Department of Biology, Lewis & Clark College, Portland, Oregon
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18
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Wang Z, Zhao H, Yuan C, Zhao D, Sun Y, Wang X, Zhang H. The RBG-1-RBG-2 complex modulates autophagy activity by regulating lysosomal biogenesis and function in C. elegans. J Cell Sci 2019; 132:jcs.234195. [PMID: 31444285 DOI: 10.1242/jcs.234195] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Accepted: 08/19/2019] [Indexed: 01/05/2023] Open
Abstract
Vici syndrome is a severe and progressive multisystem disease caused by mutations in the EPG5 gene. In patient tissues and animal models, loss of EPG5 function is associated with defective autophagy caused by accumulation of non-degradative autolysosomes, but very little is known about the mechanism underlying this cellular phenotype. Here, we demonstrate that loss of function of the RBG-1-RBG-2 complex ameliorates the autophagy defect in C. elegans epg-5 mutants. The suppression effect is independent of the complex's activity as a RAB-3 GAP and a RAB-18 GEF. Loss of rbg-1 activity promotes lysosomal biogenesis and function, and also suppresses the accumulation of non-functional autolysosomes in epg-5 mutants. The mobility of late endosome- and lysosome-associated RAB-7 is reduced in epg-5 mutants, and this defect is rescued by simultaneous loss of function of rbg-1 Expression of the GDP-bound form of RAB-7 also promotes lysosomal biogenesis and suppresses the autophagy defect in epg-5 mutants. Our study reveals that the RBG-1-RBG-2 complex acts by modulating the dynamics of membrane-associated RAB-7 to regulate lysosomal biogenesis, and provides insights into the pathogenesis of Vici syndrome.
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Affiliation(s)
- Zhaoyu Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Hongyu Zhao
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Chongzhen Yuan
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Dongfeng Zhao
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Yanan Sun
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiaochen Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hong Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China .,College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
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19
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Rakvács Z, Kucsma N, Gera M, Igriczi B, Kiss K, Barna J, Kovács D, Vellai T, Bencs L, Reisecker JM, Szoboszlai N, Szakács G. The human ABCB6 protein is the functional homologue of HMT-1 proteins mediating cadmium detoxification. Cell Mol Life Sci 2019; 76:4131-4144. [PMID: 31053883 PMCID: PMC6785578 DOI: 10.1007/s00018-019-03105-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 04/09/2019] [Accepted: 04/11/2019] [Indexed: 12/31/2022]
Abstract
ABCB6 belongs to the family of ATP-binding cassette (ABC) transporters, which transport various molecules across extra- and intra-cellular membranes, bearing significant impact on human disease and pharmacology. Although mutations in the ABCB6 gene have been linked to a variety of pathophysiological conditions ranging from transfusion incompatibility to pigmentation defects, its precise cellular localization and function is not understood. In particular, the intracellular localization of ABCB6 has been a matter of debate, with conflicting reports suggesting mitochondrial or endolysosomal expression. ABCB6 shows significant sequence identity to HMT-1 (heavy metal tolerance factor 1) proteins, whose evolutionarily conserved role is to confer tolerance to heavy metals through the intracellular sequestration of metal complexes. Here, we show that the cadmium-sensitive phenotype of Schizosaccharomyces pombe and Caenorhabditis elegans strains defective for HMT-1 is rescued by the human ABCB6 protein. Overexpression of ABCB6 conferred tolerance to cadmium and As(III) (As2O3), but not to As(V) (Na2HAsO4), Sb(V), Hg(II), or Zn(II). Inactivating mutations of ABCB6 abolished vacuolar sequestration of cadmium, effectively suppressing the cadmium tolerance phenotype. Modulation of ABCB6 expression levels in human glioblastoma cells resulted in a concomitant change in cadmium sensitivity. Our findings reveal ABCB6 as a functional homologue of the HMT-1 proteins, linking endolysosomal ABCB6 to the highly conserved mechanism of intracellular cadmium detoxification.
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Affiliation(s)
- Zsófia Rakvács
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Nóra Kucsma
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Melinda Gera
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Barbara Igriczi
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Katalin Kiss
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - János Barna
- Department of Genetics, Institute of Biology, Eötvös Loránd University, Budapest, Hungary
| | - Dániel Kovács
- Department of Genetics, Institute of Biology, Eötvös Loránd University, Budapest, Hungary
| | - Tibor Vellai
- Department of Genetics, Institute of Biology, Eötvös Loránd University, Budapest, Hungary
| | - László Bencs
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest, Hungary
| | - Johannes M Reisecker
- Department of Medicine I, Comprehensive Cancer Center, Institute of Cancer Research, Medical University of Vienna, Vienna, Austria
| | - Norbert Szoboszlai
- Department of Analytical Chemistry, Institute of Chemistry, Eötvös Loránd University, Budapest, Hungary
| | - Gergely Szakács
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary.
- Department of Medicine I, Comprehensive Cancer Center, Institute of Cancer Research, Medical University of Vienna, Vienna, Austria.
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20
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Kitamata M, Hanawa-Suetsugu K, Maruyama K, Suetsugu S. Membrane-Deformation Ability of ANKHD1 Is Involved in the Early Endosome Enlargement. iScience 2019; 17:101-118. [PMID: 31255983 PMCID: PMC6606961 DOI: 10.1016/j.isci.2019.06.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 03/22/2019] [Accepted: 06/12/2019] [Indexed: 02/06/2023] Open
Abstract
Ankyrin-repeat domains (ARDs) are conserved in large numbers of proteins. ARDs are composed of various numbers of ankyrin repeats (ANKs). ARDs often adopt curved structures reminiscent of the Bin-Amphiphysin-Rvs (BAR) domain, which is the dimeric scaffold for membrane tubulation. BAR domains sometimes have amphipathic helices for membrane tubulation and vesiculation. However, it is unclear whether ARD-containing proteins exhibit similar membrane deformation properties. We found that the ARD of ANK and KH domain-containing protein 1 (ANKHD1) dimerize and deform membranes into tubules and vesicles. Among 25 ANKs of ANKHD1, the first 15 ANKs can form a dimer and the latter 10 ANKs enable membrane tubulation and vesiculation through an adjacent amphipathic helix and a predicted curved structure with a positively charged surface, analogous to BAR domains. Knockdown and localization of ANKHD1 suggested its involvement in the negative regulation of early endosome enlargement owing to its membrane vesiculation. ANKHD1 is a large protein of 270 kDa, containing 25 ankyrin repeats ANKHD1 generates membrane tubules and vesicles by its ankyrin-repeat domain (ARD). The ARD has an amphipathic helix and a predicted curved structure, like BAR domains ANKHD1 negatively regulates early endosome enlargement by its vesiculation ability
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Affiliation(s)
- Manabu Kitamata
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma 630-0192, Japan
| | - Kyoko Hanawa-Suetsugu
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma 630-0192, Japan
| | - Kohei Maruyama
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma 630-0192, Japan
| | - Shiro Suetsugu
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma 630-0192, Japan.
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21
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Hu J, Cheng S, Wang H, Li X, Liu S, Wu M, Liu Y, Wang X. Distinct roles of two myosins in C. elegans spermatid differentiation. PLoS Biol 2019; 17:e3000211. [PMID: 30990821 PMCID: PMC6485759 DOI: 10.1371/journal.pbio.3000211] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 04/26/2019] [Accepted: 03/20/2019] [Indexed: 12/24/2022] Open
Abstract
During spermatogenesis, interconnected haploid spermatids segregate undesired cellular contents into residual bodies (RBs) before detaching from RBs. It is unclear how this differentiation process is controlled to produce individual spermatids or motile spermatozoa. Here, we developed a live imaging system to visualize and investigate this process in C. elegans. We found that non-muscle myosin 2 (NMY-2)/myosin II drives incomplete cytokinesis to generate connected haploid spermatids, which are then polarized to segregate undesired cellular contents into RBs under the control of myosin II and myosin VI. NMY-2/myosin II extends from the pseudo-cleavage furrow formed between two haploid spermatids to the spermatid poles, thus promoting RB expansion. In the meantime, defective spermatogenesis 15 (SPE-15)/myosin VI migrates from spermatids towards the expanding RB to promote spermatid budding. Loss of myosin II or myosin VI causes distinct cytoplasm segregation defects, while loss of both myosins completely blocks RB formation. We found that the final separation of spermatids from RBs is achieved through myosin VI-mediated cytokinesis, while myosin II is dispensable at this step. SPE-15/myosin VI and F-actin form a detergent-resistant actomyosin VI ring that undergoes continuous contraction to promote membrane constriction between spermatid and RB. We further identified that RGS-GAIP-interacting protein C terminus (GIPC)-1 and GIPC-2 cooperate with myosin VI to regulate contractile ring formation and spermatid release. Our study reveals distinct roles of myosin II and myosin VI in spermatid differentiation and uncovers a novel myosin VI-mediated cytokinesis process that controls spermatid release.
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Affiliation(s)
- Junyan Hu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Shiya Cheng
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Haibin Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Xin Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Sun Liu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Mengmeng Wu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Yubing Liu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Xiaochen Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
- * E-mail:
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22
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Thomas BJ, Wight IE, Chou WYY, Moreno M, Dawson Z, Homayouni A, Huang H, Kim H, Jia H, Buland JR, Wambach JA, Cole FS, Pak SC, Silverman GA, Luke CJ. CemOrange2 fusions facilitate multifluorophore subcellular imaging in C. elegans. PLoS One 2019; 14:e0214257. [PMID: 30913273 PMCID: PMC6435234 DOI: 10.1371/journal.pone.0214257] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 03/08/2019] [Indexed: 11/18/2022] Open
Abstract
Due to its ease of genetic manipulation and transparency, Caenorhabditis elegans (C. elegans) has become a preferred model system to study gene function by microscopy. The use of Aequorea victoria green fluorescent protein (GFP) fused to proteins or targeting sequences of interest, further expanded upon the utility of C. elegans by labeling subcellular structures, which enables following their disposition during development or in the presence of genetic mutations. Fluorescent proteins with excitation and emission spectra different from that of GFP accelerated the use of multifluorophore imaging in real time. We have expanded the repertoire of fluorescent proteins for use in C. elegans by developing a codon-optimized version of Orange2 (CemOrange2). Proteins or targeting motifs fused to CemOrange2 were distinguishable from the more common fluorophores used in the nematode; such as GFP, YFP, and mKate2. We generated a panel of CemOrange2 fusion constructs, and confirmed they were targeted to their correct subcellular addresses by colocalization with independent markers. To demonstrate the potential usefulness of this new panel of fluorescent protein markers, we showed that CemOrange2 fusion proteins could be used to: 1) monitor biological pathways, 2) multiplex with other fluorescent proteins to determine colocalization and 3) gain phenotypic knowledge of a human ABCA3 orthologue, ABT-4, trafficking variant in the C. elegans model organism.
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Affiliation(s)
- Brian J. Thomas
- Department of Pediatrics, Washington University School of Medicine and St. Louis Children’s Hospital, St. Louis, MO, United States of America
| | - Ira E. Wight
- Department of Pediatrics, Washington University School of Medicine and St. Louis Children’s Hospital, St. Louis, MO, United States of America
| | - Wendy Y. Y. Chou
- Department of Pediatrics, Washington University School of Medicine and St. Louis Children’s Hospital, St. Louis, MO, United States of America
| | - Marco Moreno
- Department of Pediatrics, Washington University School of Medicine and St. Louis Children’s Hospital, St. Louis, MO, United States of America
| | - Zachary Dawson
- Department of Pediatrics, Washington University School of Medicine and St. Louis Children’s Hospital, St. Louis, MO, United States of America
| | - Arielle Homayouni
- Division of Biology and Biomedical Sciences, Washington University in St. Louis, St. Louis, MO, United States of America
| | - Huiyan Huang
- Department of Pediatrics, Washington University School of Medicine and St. Louis Children’s Hospital, St. Louis, MO, United States of America
| | - Hyori Kim
- Department of Pediatrics, Washington University School of Medicine and St. Louis Children’s Hospital, St. Louis, MO, United States of America
| | - Hanna Jia
- Department of Pediatrics, Washington University School of Medicine and St. Louis Children’s Hospital, St. Louis, MO, United States of America
| | - Justin R. Buland
- Department of Pediatrics, Washington University School of Medicine and St. Louis Children’s Hospital, St. Louis, MO, United States of America
| | - Jennifer A. Wambach
- Department of Pediatrics, Washington University School of Medicine and St. Louis Children’s Hospital, St. Louis, MO, United States of America
| | - F. Sessions Cole
- Department of Pediatrics, Washington University School of Medicine and St. Louis Children’s Hospital, St. Louis, MO, United States of America
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, United States of America
| | - Stephen C. Pak
- Department of Pediatrics, Washington University School of Medicine and St. Louis Children’s Hospital, St. Louis, MO, United States of America
| | - Gary A. Silverman
- Department of Pediatrics, Washington University School of Medicine and St. Louis Children’s Hospital, St. Louis, MO, United States of America
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, United States of America
- Department of Genetics, Washington University School of Medicine, St. Louis, MO, United States of America
| | - Cliff J. Luke
- Department of Pediatrics, Washington University School of Medicine and St. Louis Children’s Hospital, St. Louis, MO, United States of America
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Best JT, Xu P, Graham TR. Phospholipid flippases in membrane remodeling and transport carrier biogenesis. Curr Opin Cell Biol 2019; 59:8-15. [PMID: 30897446 DOI: 10.1016/j.ceb.2019.02.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Revised: 02/18/2019] [Accepted: 02/20/2019] [Indexed: 12/21/2022]
Abstract
Molecular mechanisms underlying the formation of multiple classes of transport carriers or vesicles from Golgi and endosomal membranes remain poorly understood. However, one theme that has emerged over three decades is the dramatic influence of membrane lipid remodeling on transport mechanisms. A large cohort of lipid transfer proteins, lipid transporters, and lipid modifying enzymes are linked to protein sorting, carrier formation and SNARE-mediated fusion events. Here, we focus on one type of lipid transporter, phospholipid flippases in the type IV P-type ATPase (P4-ATPase) family, and discuss recent advances in defining P4-ATPase influences on membrane remodeling and vesicular transport.
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Affiliation(s)
- Jordan T Best
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States
| | - Peng Xu
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States
| | - Todd R Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States
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24
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Chen YZ, Klöditz K, Lee ES, Nguyen DP, Yuan Q, Johnson J, Lee-Yow Y, Hall A, Mitani S, Xia NS, Fadeel B, Xue D. Structure and function analysis of the C. elegans aminophospholipid translocase TAT-1. J Cell Sci 2019; 132:jcs.227660. [PMID: 30683797 DOI: 10.1242/jcs.227660] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 01/21/2019] [Indexed: 11/20/2022] Open
Abstract
The Caenorhabditis elegans aminophospholipid translocase TAT-1 maintains phosphatidylserine (PS) asymmetry in the plasma membrane and regulates endocytic transport. Despite these important functions, the structure-function relationship of this protein is poorly understood. Taking advantage of the tat-1 mutations identified by the C. elegans million mutation project, we investigated the effects of 16 single amino acid substitutions on the two functions of the TAT-1 protein. Two substitutions that alter a highly conserved PISL motif in the fourth transmembrane domain and a highly conserved DKTGT phosphorylation motif, respectively, disrupt both functions of TAT-1, leading to a vesicular gut defect and ectopic PS exposure on the cell surface, whereas most other substitutions across the TAT-1 protein, often predicted to be deleterious by bioinformatics programs, do not affect the functions of TAT-1. These results provide in vivo evidence for the importance of the PISL and DKTGT motifs in P4-type ATPases and improve our understanding of the structure-function relationship of TAT-1. Our study also provides an example of how the C. elegans million mutation project helps decipher the structure, functions, and mechanisms of action of important genes.
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Affiliation(s)
- Yu-Zen Chen
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Katharina Klöditz
- Division of Molecular Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm 17177, Sweden
| | - Eui-Seung Lee
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Diemmy Pham Nguyen
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Quan Yuan
- National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, Fujian 361005, China
| | - Jack Johnson
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Yannick Lee-Yow
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Adam Hall
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Shohei Mitani
- Department of Physiology, School of Medicine, Tokyo Women's Medical University, Tokyo 162-8666, Japan
| | - Ning-Shao Xia
- National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, Fujian 361005, China
| | - Bengt Fadeel
- Division of Molecular Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm 17177, Sweden
| | - Ding Xue
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, CO 80309, USA
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25
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Wang Q, Zhou Y, Fu R, Zhu Y, Song B, Zhong Y, Wu S, Shi Y, Wu Y, Su Y, Zhang H, He Y. Distinct autophagy-inducing abilities of similar-sized nanoparticles in cell culture and live C. elegans. NANOSCALE 2018; 10:23059-23069. [PMID: 30511716 DOI: 10.1039/c8nr05851b] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Nanomaterial-induced autophagy has raised increasing concerns. A variety of nanomaterials, conventional or recently emerged, have the capability of inducing autophagy. As a consequence, it is becoming a popular belief that induction of autophagy is a common response of cells upon exposure to nanoscale materials. In order to clarify whether the "nanoscale" size is the determining factor for the nanomaterials to induce autophagy, we utilized in vitro cultured cells and an in vivo Caenorhabditis elegans (C. elegans) model to systemically investigate the autophagy-inducing ability of nanomaterials. We selected four types of representative nanomaterials with similar sizes, namely silicon nanoparticles (SiNPs), CdTe quantum dots (QDs), carbon dots (CDs) and gold nanoparticles (AuNPs). We demonstrated that, unlike most other nanomaterials tested, no autophagosome formation was detected in cultured cells or in live C. elegans with SiNP treatment. The expression of autophagy-related genes and the lipidation of LGG-1/LC3 in cells and C. elegans also remained unchanged after the treatment of SiNPs. In addition, the ability of the nanomaterials to induce autophagy appeared to correlate with those to incur subcellular organelle damage. Together, our studies demonstrate that SiNPs do not induce autophagy in vitro or in vivo in the selected model organisms and cell lines, thus clarifying that the "nanoscale" size is not the determining factor for the nanomaterials to induce autophagy. The results also suggest that the autophagy-inducing ability of most nanomaterials could be merely a reflection of their detrimental effect on cellular structures.
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Affiliation(s)
- Qin Wang
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences (IBMS), Soochow University, Suzhou, Jiangsu 215123, China.
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26
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Shin HW, Takatsu H. Substrates of P4‐ATPases: beyond aminophospholipids (phosphatidylserine and phosphatidylethanolamine). FASEB J 2018; 33:3087-3096. [DOI: 10.1096/fj.201801873r] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Hye-Won Shin
- Graduate School of Pharmaceutical SciencesKyoto University Kyoto Japan
| | - Hiroyuki Takatsu
- Graduate School of Pharmaceutical SciencesKyoto University Kyoto Japan
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27
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Morris C, Foster OK, Handa S, Peloza K, Voss L, Somhegyi H, Jian Y, Vo MV, Harp M, Rambo FM, Yang C, Hermann GJ. Function and regulation of the Caenorhabditis elegans Rab32 family member GLO-1 in lysosome-related organelle biogenesis. PLoS Genet 2018; 14:e1007772. [PMID: 30419011 PMCID: PMC6268011 DOI: 10.1371/journal.pgen.1007772] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 11/30/2018] [Accepted: 10/17/2018] [Indexed: 02/07/2023] Open
Abstract
Cell type-specific modifications of conventional endosomal trafficking pathways lead to the formation of lysosome-related organelles (LROs). C. elegans gut granules are intestinally restricted LROs that coexist with conventional degradative lysosomes. The formation of gut granules requires the Rab32 family member GLO-1. We show that the loss of glo-1 leads to the mistrafficking of gut granule proteins but does not significantly alter conventional endolysosome biogenesis. GLO-3 directly binds to CCZ-1 and they both function to promote the gut granule association of GLO-1, strongly suggesting that together, GLO-3 and CCZ-1 activate GLO-1. We found that a point mutation in GLO-1 predicted to spontaneously activate, and function independently of it guanine nucleotide exchange factor (GEF), localizes to gut granules and partially restores gut granule protein localization in ccz-1(-) and glo-3(-) mutants. CCZ-1 forms a heterodimeric complex with SAND-1(MON1), which does not function in gut granule formation, to activate RAB-7 in trafficking pathways to conventional lysosomes. Therefore, our data suggest a model whereby the function of a Rab GEF can be altered by subunit exchange. glo-3(-) mutants, which retain low levels of GLO-3 activity, generate gut granules that lack GLO-1 and improperly accumulate RAB-7 in a SAND-1 dependent process. We show that GLO-1 and GLO-3 restrict the distribution of RAB-7 to conventional endolysosomes, providing insights into the segregation of pathways leading to conventional lysosomes and LROs.
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Affiliation(s)
- Caitlin Morris
- Department of Biology, Lewis & Clark College, Portland, Oregon, United States of America
| | - Olivia K. Foster
- Department of Biology, Lewis & Clark College, Portland, Oregon, United States of America
| | - Simran Handa
- Department of Biology, Lewis & Clark College, Portland, Oregon, United States of America
| | - Kimberly Peloza
- Department of Biology, Lewis & Clark College, Portland, Oregon, United States of America
| | - Laura Voss
- Department of Biology, Lewis & Clark College, Portland, Oregon, United States of America
| | - Hannah Somhegyi
- Department of Biology, Lewis & Clark College, Portland, Oregon, United States of America
| | - Youli Jian
- State Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - My Van Vo
- Department of Biology, Lewis & Clark College, Portland, Oregon, United States of America
| | - Marie Harp
- Department of Biology, Lewis & Clark College, Portland, Oregon, United States of America
| | - Fiona M. Rambo
- Department of Biology, Lewis & Clark College, Portland, Oregon, United States of America
| | - Chonglin Yang
- State Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Greg J. Hermann
- Department of Biology, Lewis & Clark College, Portland, Oregon, United States of America
- * E-mail:
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28
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pH dependent membrane binding of the Solanum tuberosum plant specific insert: An in silico study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:2608-2618. [PMID: 30291921 DOI: 10.1016/j.bbamem.2018.10.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 09/27/2018] [Accepted: 10/01/2018] [Indexed: 01/07/2023]
Abstract
The Solanum tuberosum plant-specific insert (StPSI) has been shown to possess potent antimicrobial activity against both human and plant pathogens. Furthermore, in vitro, the StPSI is capable of fusing phospholipid vesicles, provided the conditions of net anionic vesicle charge and acidic pH are met. Constant pH replica-exchange simulations indicate several acidic residues on the dimer have highly perturbed pKas (<3.0; E15, D28, E85 & E100) due to involvement in salt bridges. After setting the pH of the system to either 3.0 or 7.4, all-atom simulations provided details of the effect of pH on secondary structural elements, particularly in the previously unresolved crystallographic structure of the loop section. Coarse-grained dimer-bilayer simulations demonstrated that at pH 7.4, the dimer had no affinity for neutral or anionic membranes over the course of 1 μs simulations. Conversely, at pH 3.0 two binding modes were observed. Mode 1 is mediated primarily via strong N-terminal interactions on one monomer only, whereas in mode 2, N- and C-terminal residues of one monomer and numerous polar and basic residues on the second monomer, particularly in the third helix, participate in membrane interactions. Mode 2 was accompanied by re-orientation of the dimer to a more vertical position with respect to helices 1 and 4, positioning the dimer for membrane interactions. These results offer the first examination at near-atomic resolution of residues mediating the StPSI-membrane interactions, and allow for the postulation of a possible fusion mechanism.
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29
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Li Y, Wang C, Huang Y, Fu R, Zheng H, Zhu Y, Shi X, Padakanti PK, Tu Z, Su X, Zhang H. C. Elegans Fatty Acid Two-Hydroxylase Regulates Intestinal Homeostasis by Affecting Heptadecenoic Acid Production. Cell Physiol Biochem 2018; 49:947-960. [PMID: 30184537 DOI: 10.1159/000493226] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 08/27/2018] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND/AIMS The hydroxylation of fatty acids at the C-2 position is the first step of fatty acid α-oxidation and generates sphingolipids containing 2-hydroxy fatty acyl moieties. Fatty acid 2-hydroxylation is catalyzed by Fatty acid 2-hydroxylase (FA2H) enzyme. However, the precise roles of FA2H and fatty acid 2-hydroxylation in whole cell homeostasis still remain unclear. METHODS Here we utilize Caenorhabditis elegans as the model and systemically investigate the physiological functions of FATH-1/C25A1.5, the highly conserved worm homolog for mammalian FA2H enzyme. Immunostaining, dye-staining and translational fusion reporters were used to visualize FATH-1 protein and a variety of subcellular structures. The "click chemistry" method was employed to label 2-OH fatty acid in vivo. Global and tissue-specific RNAi knockdown experiments were performed to inactivate FATH-1 function. Lipid analysis of the fath-1 deficient mutants was achieved by mass spectrometry. RESULTS C. elegans FATH-1 is expressed at most developmental stages and in most tissues. Loss of fath-1 expression results in severe growth retardation and shortened lifespan. FATH-1 function is crucially required in the intestine but not the epidermis with stereospecificity. The "click chemistry" labeling technique showed that the FATH-1 metabolites are mainly enriched in membrane structures preferable to the apical side of the intestinal cells. At the subcellular level, we found that loss of fath-1 expression inhibits lipid droplets formation, as well as selectively disrupts peroxisomes and apical endosomes. Lipid analysis of the fath-1 deficient animals revealed a significant reduction in the content of heptadecenoic acid, while other major FAs remain unaffected. Feeding of exogenous heptadecenoic acid (C17: 1), but not oleic acid (C18: 1), rescues the global and subcellular defects of fath-1 knockdown worms. CONCLUSION Our study revealed that FATH-1 and its catalytic products are highly specific in the context of chirality, C-chain length, spatial distribution, as well as the types of cellular organelles they affect. Such an unexpected degree of specificity for the synthesis and functions of hydroxylated FAs helps to regulate protein transport and fat metabolism, therefore maintaining the cellular homeostasis of the intestinal cells. These findings may help our understanding of FA2H functions across species, and offer potential therapeutical targets for treating FA2H-related diseases.
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Affiliation(s)
- Yuanbao Li
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China
| | - Chunxia Wang
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China
| | - Yikai Huang
- Department of Biochemistry and Molecular Biology, Soochow University Medical College, Suzhou, China
| | - Rong Fu
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China
| | - Hanxi Zheng
- Department of Biochemistry and Molecular Biology, Soochow University Medical College, Suzhou, China
| | - Yi Zhu
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China
| | - Xiaoruo Shi
- Department of Biochemistry and Molecular Biology, Soochow University Medical College, Suzhou, China
| | - Prashanth K Padakanti
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Zhude Tu
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Xiong Su
- Department of Biochemistry and Molecular Biology, Soochow University Medical College, Suzhou, China.,Center for Human Nutrition, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Huimin Zhang
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China
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30
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Takasugi N, Araya R, Kamikubo Y, Kaneshiro N, Imaoka R, Jin H, Kashiyama T, Hashimoto Y, Kurosawa M, Uehara T, Nukina N, Sakurai T. TMEM30A is a candidate interacting partner for the β-carboxyl-terminal fragment of amyloid-β precursor protein in endosomes. PLoS One 2018; 13:e0200988. [PMID: 30086173 PMCID: PMC6080755 DOI: 10.1371/journal.pone.0200988] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 07/08/2018] [Indexed: 11/19/2022] Open
Abstract
Although the aggregation of amyloid-β peptide (Aβ) clearly plays a central role in the pathogenesis of Alzheimer's disease (AD), endosomal traffic dysfunction is considered to precede Aβ aggregation and trigger AD pathogenesis. A body of evidence suggests that the β-carboxyl-terminal fragment (βCTF) of amyloid-β precursor protein (APP), which is the direct precursor of Aβ, accumulates in endosomes and causes vesicular traffic impairment. However, the mechanism underlying this impairment remains unclear. Here we identified TMEM30A as a candidate partner for βCTF. TMEM30A is a subcomponent of lipid flippase that translocates phospholipids from the outer to the inner leaflet of the lipid bilayer. TMEM30A physically interacts with βCTF in endosomes and may impair vesicular traffic, leading to abnormally enlarged endosomes. APP traffic is also concomitantly impaired, resulting in the accumulation of APP-CTFs, including βCTF. In addition, we found that expressed BACE1 accumulated in enlarged endosomes and increased Aβ production. Our data suggested that TMEM30A is involved in βCTF-dependent endosome abnormalities that are related to Aβ overproduction.
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Affiliation(s)
- Nobumasa Takasugi
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan
- Department of Medicinal Pharmacology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Runa Araya
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan
| | - Yuji Kamikubo
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan
| | - Nanaka Kaneshiro
- Department of Medicinal Pharmacology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Ryosuke Imaoka
- Department of Medicinal Pharmacology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Hao Jin
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan
| | - Taku Kashiyama
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan
| | - Yoshie Hashimoto
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan
| | - Masaru Kurosawa
- Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Saitama, Japan
| | - Takashi Uehara
- Department of Medicinal Pharmacology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Nobuyuki Nukina
- Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Saitama, Japan
- Laboratory of Structural Neuropathology, Doshisha University Graduate School of Brain Science, Kyoto, Japan
- Department of Neuroscience for Neurodegenerative Disorders, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan
| | - Takashi Sakurai
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan
- Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Saitama, Japan
- * E-mail:
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31
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Phosphatidylserine exposure mediated by ABC transporter activates the integrin signaling pathway promoting axon regeneration. Nat Commun 2018; 9:3099. [PMID: 30082731 PMCID: PMC6079064 DOI: 10.1038/s41467-018-05478-w] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 07/02/2018] [Indexed: 12/22/2022] Open
Abstract
Following axon injury, a cascade of signaling events is triggered to initiate axon regeneration. However, the mechanisms regulating axon regeneration are not well understood at present. In Caenorhabditis elegans, axon regeneration utilizes many of the components involved in phagocytosis, including integrin and Rac GTPase. Here, we identify the transthyretin (TTR)-like protein TTR-11 as a component functioning in axon regeneration upstream of integrin. We show that TTR-11 binds to both the extracellular domain of integrin-α and phosphatidylserine (PS). Axon injury induces the accumulation of PS around the injured axons in a manner dependent on TTR-11, the ABC transporter CED-7, and the caspase CED-3. Furthermore, we demonstrate that CED-3 activates CED-7 during axon regeneration. Thus, TTR-11 functions to link the PS injury signal to activation of the integrin pathway, which then initiates axon regeneration.
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33
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Abstract
Membrane biology seeks to understand how lipids and proteins within bilayers assemble into large structures such as organelles and the plasma membranes. Historically, lipids were thought to merely provide structural support for bilayer formation and membrane protein function. Research has now revealed that phospholipid metabolism regulates nearly all cellular processes. Sophisticated techniques helped identify >10,000 lipid species suggesting that lipids support many biological processes. Here, we highlight the synthesis of the most abundant glycerophospholipid classes and their distribution in organelles. We review vesicular and nonvesicular transport pathways shuttling lipids between organelles and discuss lipid regulators of membrane trafficking and second messengers in eukaryotic cells.
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Affiliation(s)
- Yanbo Yang
- From the Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario M5B 1W8.,the Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, and
| | - Minhyoung Lee
- From the Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario M5B 1W8.,the Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, and
| | - Gregory D Fairn
- From the Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario M5B 1W8, .,the Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, and.,the Department of Surgery, University of Toronto, Toronto, Ontario M5T 1P5, Canada
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Extracellular vesicle budding is inhibited by redundant regulators of TAT-5 flippase localization and phospholipid asymmetry. Proc Natl Acad Sci U S A 2018; 115:E1127-E1136. [PMID: 29367422 PMCID: PMC5819400 DOI: 10.1073/pnas.1714085115] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cells release extracellular vesicles (EVs) that mediate intercellular communication and repair damaged membranes. Despite the pleiotropic functions of EVs in vitro, their in vivo function is debated, largely because it is unclear how to induce or inhibit their formation. In particular, the mechanisms of EV release by plasma membrane budding or ectocytosis are poorly understood. We previously showed that TAT-5 phospholipid flippase activity maintains the asymmetric localization of the lipid phosphatidylethanolamine (PE) in the plasma membrane and inhibits EV budding by ectocytosis in Caenorhabditis elegans However, no proteins that inhibit ectocytosis upstream of TAT-5 were known. Here, we identify TAT-5 regulators associated with retrograde endosomal recycling: PI3Kinase VPS-34, Beclin1 homolog BEC-1, DnaJ protein RME-8, and the uncharacterized Dopey homolog PAD-1. PI3Kinase, RME-8, and semiredundant sorting nexins are required for the plasma membrane localization of TAT-5, which is important to maintain PE asymmetry and inhibit EV release. PAD-1 does not directly regulate TAT-5 localization, but is required for the lipid flipping activity of TAT-5. PAD-1 also has roles in endosomal trafficking with the GEF-like protein MON-2, which regulates PE asymmetry and EV release redundantly with sorting nexins independent of the core retromer. Thus, in addition to uncovering redundant intracellular trafficking pathways, our study identifies additional proteins that regulate EV release. This work pinpoints TAT-5 and PE as key regulators of plasma membrane budding, further supporting the model that PE externalization drives ectocytosis.
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Early endosome as a pathogenic target for antiphosphatidylethanolamine antibodies. Proc Natl Acad Sci U S A 2017; 114:13798-13803. [PMID: 29229837 DOI: 10.1073/pnas.1714027115] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Phosphatidylethanolamine (PE) is a major phospholipid species with important roles in membrane trafficking and reorganization. Accumulating clinical data indicate that the presence of circulating antibodies against PE is positively correlated with the symptoms of antiphospholipid syndromes (APS), including thrombosis and repeated pregnancy loss. However, PE is generally sequestered inside a normal resting cell, and the mechanism by which circulating anti-PE antibodies access cellular PE remains unknown. The studies presented here were conducted with synthetic PE-binding agents, plasma samples from patients with anti-PE autoimmunity, and purified anti-PE antibodies. The results suggest that the cellular vulnerability to anti-PE antibodies may be mediated by the binding of PE molecules in the membrane of the early endosome. Endosomal PE binding led to functional changes in endothelial cells, including declines in proliferation and increases in the production of reactive oxygen species, as well as the expression of inflammatory molecules. Collectively, our findings provide insight into the etiology of anti-PE autoimmunity and, because endosomes are of central importance in almost all types of cells, could have important implications for a wide range of biological processes.
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36
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Watts JL, Ristow M. Lipid and Carbohydrate Metabolism in Caenorhabditis elegans. Genetics 2017; 207:413-446. [PMID: 28978773 PMCID: PMC5629314 DOI: 10.1534/genetics.117.300106] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 08/02/2017] [Indexed: 12/14/2022] Open
Abstract
Lipid and carbohydrate metabolism are highly conserved processes that affect nearly all aspects of organismal biology. Caenorhabditis elegans eat bacteria, which consist of lipids, carbohydrates, and proteins that are broken down during digestion into fatty acids, simple sugars, and amino acid precursors. With these nutrients, C. elegans synthesizes a wide range of metabolites that are required for development and behavior. In this review, we outline lipid and carbohydrate structures as well as biosynthesis and breakdown pathways that have been characterized in C. elegans We bring attention to functional studies using mutant strains that reveal physiological roles for specific lipids and carbohydrates during development, aging, and adaptation to changing environmental conditions.
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Affiliation(s)
- Jennifer L Watts
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, Washington 99164
| | - Michael Ristow
- Energy Metabolism Laboratory, Institute of Translational Medicine, Department of Health Sciences and Technology, Swiss Federal Institute of Technology Zurich, 8603 Schwerzenbach-Zurich, Switzerland
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Cell surface binding, uptaking and anticancer activity of L-K6, a lysine/leucine-rich peptide, on human breast cancer MCF-7 cells. Sci Rep 2017; 7:8293. [PMID: 28811617 PMCID: PMC5557901 DOI: 10.1038/s41598-017-08963-2] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Accepted: 07/20/2017] [Indexed: 01/06/2023] Open
Abstract
Cell surface binding and internalization are critical for the specific targeting and biofunctions of some cationic antimicrobial peptides (CAPs) with anticancer activities. However, the detailed cellular process for CAPs interacting with cancer cells and the exact molecular basis for their anticancer effects are still far from being fully understood. In the present study, we examined the cell surface binding, uptaking and anti-cancer activity of L-K6, a lysine/leucine-rich CAP, in human MCF-7 breast cancer cells. We found that L-K6 preferentially interact with MCF-7 cells. This tumor-targeting property of L-K6 might be partially due to its interactions with the surface exposed and negatively charged phosphatidylserine. Subsequently, L-K6 could internalize into MCF-7 cells mainly through a clathrin-independent macropinocytosis, without significant cell surface disruption. Finally, the internalized L-K6 induced a dramatic nuclear damage and MCF-7 cell death, without significant cytoskeleton disruption and mitochondrial impairment. This cytotoxicity of L-K6 against MCF-7 cancer cells could be further confirmed by using a mouse xenograft model. In summary, all these findings outlined the cellular process and cytotoxicity of L-K6 in MCF-7 cancer cells, and might help understand the complicated interactions between CAPs and cancer cells.
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Chun H, Sharma AK, Lee J, Chan J, Jia S, Kim BE. The Intestinal Copper Exporter CUA-1 Is Required for Systemic Copper Homeostasis in Caenorhabditis elegans. J Biol Chem 2016; 292:1-14. [PMID: 27881675 DOI: 10.1074/jbc.m116.760876] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 11/15/2016] [Indexed: 12/23/2022] Open
Abstract
Copper plays key catalytic and regulatory roles in biochemical processes essential for normal growth, development, and health. Defects in copper metabolism cause Menkes and Wilson's disease, myeloneuropathy, and cardiovascular disease and are associated with other pathophysiological states. Consequently, it is critical to understand the mechanisms by which organisms control the acquisition, distribution, and utilization of copper. The intestinal enterocyte is a key regulatory point for copper absorption into the body; however, the mechanisms by which intestinal cells transport copper to maintain organismal copper homeostasis are poorly understood. Here, we identify a mechanism by which organismal copper homeostasis is maintained by intestinal copper exporter trafficking that is coordinated with extraintestinal copper levels in Caenorhabditis elegans Specifically, we show that CUA-1, the C. elegans homolog of ATP7A/B, localizes to lysosome-like organelles (gut granules) in the intestine under copper overload conditions for copper detoxification, whereas copper deficiency results in a redistribution of CUA-1 to basolateral membranes for copper efflux to peripheral tissues. Worms defective in gut granule biogenesis exhibit defects in copper sequestration and increased susceptibility to toxic copper levels. Interestingly, however, a splice isoform CUA-1.2 that lacks a portion of the N-terminal domain is targeted constitutively to the basolateral membrane irrespective of dietary copper concentration. Our studies establish that CUA-1 is a key intestinal copper exporter and that its trafficking is regulated to maintain systemic copper homeostasis. C. elegans could therefore be exploited as a whole-animal model system to study regulation of intra- and intercellular copper trafficking pathways.
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Affiliation(s)
- Haarin Chun
- From the Department of Animal and Avian Sciences
| | | | - Jaekwon Lee
- the Redox Biology Center, Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588, and
| | - Jefferson Chan
- the Department of Chemistry, University of California at Berkeley, Berkeley, California 94720
| | - Shang Jia
- the Department of Chemistry, University of California at Berkeley, Berkeley, California 94720
| | - Byung-Eun Kim
- From the Department of Animal and Avian Sciences, .,Biological Sciences Graduate Program, University of Maryland, College Park, Maryland 20742
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van der Mark VA, Ghiboub M, Marsman C, Zhao J, van Dijk R, Hiralall JK, Ho-Mok KS, Castricum Z, de Jonge WJ, Oude Elferink RPJ, Paulusma CC. Phospholipid flippases attenuate LPS-induced TLR4 signaling by mediating endocytic retrieval of Toll-like receptor 4. Cell Mol Life Sci 2016; 74:715-730. [PMID: 27628304 PMCID: PMC5272906 DOI: 10.1007/s00018-016-2360-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 08/31/2016] [Accepted: 09/06/2016] [Indexed: 01/01/2023]
Abstract
P4-ATPases are lipid flippases that catalyze the transport of phospholipids to create membrane phospholipid asymmetry and to initiate the biogenesis of transport vesicles. Here we show, for the first time, that lipid flippases are essential to dampen the inflammatory response and to mediate the endotoxin-induced endocytic retrieval of Toll-like receptor 4 (TLR4) in human macrophages. Depletion of CDC50A, the β-subunit that is crucial for the activity of multiple P4-ATPases, resulted in endotoxin-induced hypersecretion of proinflammatory cytokines, enhanced MAP kinase signaling and constitutive NF-κB activation. In addition, CDC50A-depleted THP-1 macrophages displayed reduced tolerance to endotoxin. Moreover, endotoxin-induced internalization of TLR4 was strongly reduced and coincided with impaired endosomal MyD88-independent signaling. The phenotype of CDC50A-depleted cells was also induced by separate knockdown of two P4-ATPases, namely ATP8B1 and ATP11A. We conclude that lipid flippases are novel elements of the innate immune response that are essential to attenuate the inflammatory response, possibly by mediating endotoxin-induced internalization of TLR4.
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Affiliation(s)
- Vincent A van der Mark
- Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, Meibergdreef 69-71, 1105 BK, Amsterdam, The Netherlands
| | - Mohammed Ghiboub
- Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, Meibergdreef 69-71, 1105 BK, Amsterdam, The Netherlands
| | - Casper Marsman
- Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, Meibergdreef 69-71, 1105 BK, Amsterdam, The Netherlands
| | - Jing Zhao
- Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, Meibergdreef 69-71, 1105 BK, Amsterdam, The Netherlands
| | - Remco van Dijk
- Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, Meibergdreef 69-71, 1105 BK, Amsterdam, The Netherlands
| | - Johan K Hiralall
- Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, Meibergdreef 69-71, 1105 BK, Amsterdam, The Netherlands
| | - Kam S Ho-Mok
- Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, Meibergdreef 69-71, 1105 BK, Amsterdam, The Netherlands
| | - Zoë Castricum
- Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, Meibergdreef 69-71, 1105 BK, Amsterdam, The Netherlands
| | - Wouter J de Jonge
- Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, Meibergdreef 69-71, 1105 BK, Amsterdam, The Netherlands
| | - Ronald P J Oude Elferink
- Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, Meibergdreef 69-71, 1105 BK, Amsterdam, The Netherlands
| | - Coen C Paulusma
- Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, Meibergdreef 69-71, 1105 BK, Amsterdam, The Netherlands.
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Pomorski TG, Menon AK. Lipid somersaults: Uncovering the mechanisms of protein-mediated lipid flipping. Prog Lipid Res 2016; 64:69-84. [PMID: 27528189 DOI: 10.1016/j.plipres.2016.08.003] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 08/10/2016] [Indexed: 12/22/2022]
Abstract
Membrane lipids diffuse rapidly in the plane of the membrane but their ability to flip spontaneously across a membrane bilayer is hampered by a significant energy barrier. Thus spontaneous flip-flop of polar lipids across membranes is very slow, even though it must occur rapidly to support diverse aspects of cellular life. Here we discuss the mechanisms by which rapid flip-flop occurs, and what role lipid flipping plays in membrane homeostasis and cell growth. We focus on conceptual aspects, highlighting mechanistic insights from biochemical and in silico experiments, and the recent, ground-breaking identification of a number of lipid scramblases.
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Affiliation(s)
- Thomas Günther Pomorski
- Faculty of Chemistry and Biochemistry, Molecular Biochemistry, Ruhr University Bochum, Universitätstrasse 150, D-44780 Bochum, Germany; Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark.
| | - Anant K Menon
- Department of Biochemistry, Weill Cornell Medical College, 1300 York Avenue, New York, NY 10065, USA.
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Directed evolution of a sphingomyelin flippase reveals mechanism of substrate backbone discrimination by a P4-ATPase. Proc Natl Acad Sci U S A 2016; 113:E4460-6. [PMID: 27432949 DOI: 10.1073/pnas.1525730113] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Phospholipid flippases in the type IV P-type ATPase (P4-ATPases) family establish membrane asymmetry and play critical roles in vesicular transport, cell polarity, signal transduction, and neurologic development. All characterized P4-ATPases flip glycerophospholipids across the bilayer to the cytosolic leaflet of the membrane, but how these enzymes distinguish glycerophospholipids from sphingolipids is not known. We used a directed evolution approach to examine the molecular mechanisms through which P4-ATPases discriminate substrate backbone. A mutagenesis screen in the yeast Saccharomyces cerevisiae has identified several gain-of-function mutations in the P4-ATPase Dnf1 that facilitate the transport of a novel lipid substrate, sphingomyelin. We found that a highly conserved asparagine (N220) in the first transmembrane segment is a key enforcer of glycerophospholipid selection, and specific substitutions at this site allow transport of sphingomyelin.
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Wang P, Liu H, Wang Y, Liu O, Zhang J, Gleason A, Yang Z, Wang H, Shi A, Grant BD. RAB-10 Promotes EHBP-1 Bridging of Filamentous Actin and Tubular Recycling Endosomes. PLoS Genet 2016; 12:e1006093. [PMID: 27272733 PMCID: PMC4894640 DOI: 10.1371/journal.pgen.1006093] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Accepted: 05/10/2016] [Indexed: 12/21/2022] Open
Abstract
EHBP-1 (Ehbp1) is a conserved regulator of endocytic recycling, acting as an effector of small GTPases including RAB-10 (Rab10). Here we present evidence that EHBP-1 associates with tubular endosomal phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2] enriched membranes through an N-terminal C2-like (NT-C2) domain, and define residues within the NT-C2 domain that mediate membrane interaction. Furthermore, our results indicate that the EHBP-1 central calponin homology (CH) domain binds to actin microfilaments in a reaction that is stimulated by RAB-10(GTP). Loss of any aspect of this RAB-10/EHBP-1 system in the C. elegans intestinal epithelium leads to retention of basolateral recycling cargo in endosomes that have lost their normal tubular endosomal network (TEN) organization. We propose a mechanism whereby RAB-10 promotes the ability of endosome-bound EHBP-1 to also bind to the actin cytoskeleton, thereby promoting endosomal tubulation. Endosomes are intracellular organelles that sort protein and lipid components integral to the membrane, as well as more loosely associated lumenal content, for delivery to distinct intracellular destinations. Endosomes associated with recycling cargo back to the plasma membrane are often tubular in morphology, and this morphology is thought to be essential for recycling function. Our previous work identified a particularly dramatic network of endosomal tubules involved in membrane protein recycling in the basolateral intestinal epithelial cells of C. elegans. Our subsequent genetic analysis of basolateral recycling in this system identified a number of key regulators of these endosomes, including the small GTPase RAB-10 and its effector EHBP-1. Our new work presented here shows that EHBP-1 promotes endosomal tubulation by linking the membrane lipid PI(4,5)P2 to the actin cytoskeleton, and that the linkage of EHBP-1 to actin is enhanced by the interaction of EHBP-1 with RAB-10. This work has broad implications for how endosomal tubulation occurs in all cells, and has specific implications for the role of EHBP-1 in related processes such as insulin-stimulated recycling of glucose transporters in human adipocytes, a process intimately linked to type II diabetes.
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Affiliation(s)
- Peixiang Wang
- Department of Medical Genetics, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Hang Liu
- Department of Medical Genetics, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yu Wang
- Department of Medical Genetics, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Ou Liu
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey, United States of America
| | - Jing Zhang
- Department of Medical Genetics, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Adenrele Gleason
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey, United States of America
| | - Zhenrong Yang
- Department of Medical Genetics, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Hui Wang
- Department of Medical Genetics, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Anbing Shi
- Department of Medical Genetics, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Institute for Brain Research, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Key Laboratory of Neurological Disease of National Education Ministry, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- * E-mail: (AS); (BDG)
| | - Barth D. Grant
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey, United States of America
- * E-mail: (AS); (BDG)
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Nagata S, Suzuki J, Segawa K, Fujii T. Exposure of phosphatidylserine on the cell surface. Cell Death Differ 2016; 23:952-61. [PMID: 26891692 DOI: 10.1038/cdd.2016.7] [Citation(s) in RCA: 300] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 01/11/2016] [Indexed: 12/15/2022] Open
Abstract
Phosphatidylserine (PtdSer) is a phospholipid that is abundant in eukaryotic plasma membranes. An ATP-dependent enzyme called flippase normally keeps PtdSer inside the cell, but PtdSer is exposed by the action of scramblase on the cell's surface in biological processes such as apoptosis and platelet activation. Once exposed to the cell surface, PtdSer acts as an 'eat me' signal on dead cells, and creates a scaffold for blood-clotting factors on activated platelets. The molecular identities of the flippase and scramblase that work at plasma membranes have long eluded researchers. Indeed, their identity as well as the mechanism of the PtdSer exposure to the cell surface has only recently been revealed. Here, we describe how PtdSer is exposed in apoptotic cells and in activated platelets, and discuss PtdSer exposure in other biological processes.
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Affiliation(s)
- S Nagata
- Laboratory of Biochemistry & Immunology, Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
| | - J Suzuki
- Laboratory of Biochemistry & Immunology, Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
| | - K Segawa
- Laboratory of Biochemistry & Immunology, Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
| | - T Fujii
- Laboratory of Biochemistry & Immunology, Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
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Palmisano NJ, Meléndez A. Detection of Autophagy in Caenorhabditis elegans Using GFP::LGG-1 as an Autophagy Marker. Cold Spring Harb Protoc 2016; 2016:pdb.prot086496. [PMID: 26729905 DOI: 10.1101/pdb.prot086496] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In yeast and mammalian cells, the autophagy protein Atg8/LC3 (microtubule-associated proteins 1A/1B light chain 3B encoded by MAP1LC3B) has been the marker of choice to detect double-membraned autophagosomes that are produced during the process of autophagy. A lipid-conjugated form of Atg8/LC3B is localized to the inner and outer membrane of the early-forming structure known as the phagophore. During maturation of autophagosomes, Atg8/LC3 bound to the inner autophagosome membrane remains in situ as the autophagosomes fuse with lysosomes. The nematode Caenorhabditis elegans is thought to conduct a similar process, meaning that tagging the nematode ortholog of Atg8/LC3-known as LGG-1-with a fluorophore has become a widely accepted method to visualize autophagosomes. Under normal growth conditions, GFP-modified LGG-1 displays a diffuse expression pattern throughout a variety of tissues, whereas, when under conditions that induce autophagy, the GFP::LGG-1 tag labels positive punctate structures, and its overall level of expression increases. Here, we present a protocol for using fluorescent reporters of LGG-1 coupled to GFP to monitor autophagosomes in vivo. We also discuss the use of alternative fluorescent markers and the possible utility of the LGG-1 paralog LGG-2.
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Affiliation(s)
- Nicholas J Palmisano
- Department of Biology, Queens College-CUNY, Flushing, New York 11367; The Graduate Center, The City University of New York, New York 10016
| | - Alicia Meléndez
- Department of Biology, Queens College-CUNY, Flushing, New York 11367; The Graduate Center, The City University of New York, New York 10016
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Montigny C, Lyons J, Champeil P, Nissen P, Lenoir G. On the molecular mechanism of flippase- and scramblase-mediated phospholipid transport. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1861:767-783. [PMID: 26747647 DOI: 10.1016/j.bbalip.2015.12.020] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 12/20/2015] [Accepted: 12/28/2015] [Indexed: 11/20/2022]
Abstract
Phospholipid flippases are key regulators of transbilayer lipid asymmetry in eukaryotic cell membranes, critical to many trafficking and signaling pathways. P4-ATPases, in particular, are responsible for the uphill transport of phospholipids from the exoplasmic to the cytosolic leaflet of the plasma membrane, as well as membranes of the late secretory/endocytic pathways, thereby establishing transbilayer asymmetry. Recent studies combining cell biology and biochemical approaches have improved our understanding of the path taken by lipids through P4-ATPases. Additionally, identification of several protein families catalyzing phospholipid 'scrambling', i.e. disruption of phospholipid asymmetry through energy-independent bi-directional phospholipid transport, as well as the recent report of the structure of such a scramblase, opens the way to a deeper characterization of their mechanism of action. Here, we discuss the molecular nature of the mechanism by which lipids may 'flip' across membranes, with an emphasis on active lipid transport catalyzed by P4-ATPases. This article is part of a Special Issue entitled: The cellular lipid landscape edited by Tim P. Levine and Anant K. Menon.
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Affiliation(s)
- Cédric Montigny
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette, France
| | - Joseph Lyons
- DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, and PUMPkin, Danish National Research Foundation, Aarhus University, Department of Molecular Biology and Genetics, Gustav Wieds Vej 10C, 8000 Aarhus C, Denmark
| | - Philippe Champeil
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette, France
| | - Poul Nissen
- DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, and PUMPkin, Danish National Research Foundation, Aarhus University, Department of Molecular Biology and Genetics, Gustav Wieds Vej 10C, 8000 Aarhus C, Denmark
| | - Guillaume Lenoir
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette, France.
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Matsuzaka Y, Hayashi H, Kusuhara H. Impaired Hepatic Uptake by Organic Anion-Transporting Polypeptides Is Associated with Hyperbilirubinemia and Hypercholanemia in Atp11c Mutant Mice. Mol Pharmacol 2015; 88:1085-92. [PMID: 26399598 DOI: 10.1124/mol.115.100578] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Accepted: 09/22/2015] [Indexed: 12/28/2022] Open
Abstract
Biliary excretion of organic anions, such as bile acids (BAs), is the main osmotic driving force for bile formation, and its impairment induces intrahepatic cholestasis. We investigated the involvement of Atp11c in the hepatic transport of organic anions using Atp11c mutant mice, which exhibit hypercholanemia and hyperbilirubinemia. Pharmacokinetic analysis following a constant intravenous infusion in Atp11c mutant mice showed decreased hepatic sinusoidal uptake and intact biliary secretion of [(3)H]17β estradiol 17β-d-glucuronide. Consistent with this result, compared with cells and membranes from control mice, isolated hepatocytes, and liver plasma membranes from Atp11c mutant mice had a much lower uptake of [(3)H]17β estradiol 17β-d-glucuronide and expression of organic anion-transporting polypeptides, which are transporters responsible for hepatic uptake of unconjugated BAs and organic anions, including bilirubin glucuronides. Uptake of [(3)H]TC into hepatocytes and expression of Na(+)-taurocholate cotransporting polypeptide in liver plasma membranes, which mediates hepatic uptake of conjugated BAs, was also lower in the Atp11c mutant mice. Bile flow rate, biliary BA concentration, and expression of hepatobiliary transporters did not differ between Atp11c mutant mice and control mice. These results suggest that Atp11c mediates the transport of BAs and organic anions across the sinusoidal membrane, but not the canalicular membrane, by regulating the abundance of transporters. Atp11c is a candidate gene for genetically undiagnosed cases of hypercholanemia and hyperbilirubinemia, but not of intrahepatic cholestasis. This gene may influence the pharmacological and adverse effect of drugs because organic anion-transporting polypeptides regulate their systemic exposure.
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Affiliation(s)
- Yusuke Matsuzaka
- Laboratory of Molecular Pharmacokinetics, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Hisamitsu Hayashi
- Laboratory of Molecular Pharmacokinetics, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Hiroyuki Kusuhara
- Laboratory of Molecular Pharmacokinetics, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
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Zou W, Yadav S, DeVault L, Jan YN, Sherwood DR. RAB-10-Dependent Membrane Transport Is Required for Dendrite Arborization. PLoS Genet 2015; 11:e1005484. [PMID: 26394140 PMCID: PMC4578882 DOI: 10.1371/journal.pgen.1005484] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 08/05/2015] [Indexed: 01/07/2023] Open
Abstract
Formation of elaborately branched dendrites is necessary for the proper input and connectivity of many sensory neurons. Previous studies have revealed that dendritic growth relies heavily on ER-to-Golgi transport, Golgi outposts and endocytic recycling. How new membrane and associated cargo is delivered from the secretory and endosomal compartments to sites of active dendritic growth, however, remains unknown. Using a candidate-based genetic screen in C. elegans, we have identified the small GTPase RAB-10 as a key regulator of membrane trafficking during dendrite morphogenesis. Loss of rab-10 severely reduced proximal dendritic arborization in the multi-dendritic PVD neuron. RAB-10 acts cell-autonomously in the PVD neuron and localizes to the Golgi and early endosomes. Loss of function mutations of the exocyst complex components exoc-8 and sec-8, which regulate tethering, docking and fusion of transport vesicles at the plasma membrane, also caused proximal dendritic arborization defects and led to the accumulation of intracellular RAB-10 vesicles. In rab-10 and exoc-8 mutants, the trans-membrane proteins DMA-1 and HPO-30, which promote PVD dendrite stabilization and branching, no longer localized strongly to the proximal dendritic membranes and instead were sequestered within intracellular vesicles. Together these results suggest a crucial role for the Rab10 GTPase and the exocyst complex in controlling membrane transport from the secretory and/or endosomal compartments that is required for dendritic growth. Dendrites are cellular extensions from neurons that gather information from other neurons or cues from the external environment to convey to the nervous system of an organism. Dendrites are often extensively branched, raising the question of how neurons supply plasma membrane and dendrite specific proteins from the source of synthesis inside the cell to developing dendrites. We have examined membrane trafficking in the PVD neuron in the nematode worm C. elegans to investigate how new membrane and dendrite proteins are trafficked. The PVD neuron is easy to visualize and has remarkably long and widely branched dendrites positioned along the skin of the worm, which transmits information about harsh touch and cold temperature to the nervous system. We have discovered that a key organizer of vesicle trafficking, the RAB-10 protein, localizes to membrane vesicles and is required to traffic these vesicles that contain plasma membrane and dendrite proteins to the growing PVD dendrite. Further, our work revealed that a complex of proteins, termed the exocyst, that helps fuse membrane vesicles at the plasma membrane, localizes with RAB-10 and is required for dendrite branching. Together, our work has revealed a novel mechanism for how neurons build dendrites that could be used to help repair damaged neurons in human diseases and during aging.
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Affiliation(s)
- Wei Zou
- Department of Biology, Duke University, Durham, North Carolina, United States of America
| | - Smita Yadav
- Howard Hughes Medical Institute, Department of Physiology, University of California, San Francisco, San Francisco, California, United States of America
| | - Laura DeVault
- Howard Hughes Medical Institute, Department of Physiology, University of California, San Francisco, San Francisco, California, United States of America
| | - Yuh Nung Jan
- Howard Hughes Medical Institute, Department of Physiology, University of California, San Francisco, San Francisco, California, United States of America
| | - David R. Sherwood
- Department of Biology, Duke University, Durham, North Carolina, United States of America
- * E-mail:
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Zhou Y, Wang Q, Song B, Wu S, Su Y, Zhang H, He Y. A real-time documentation and mechanistic investigation of quantum dots-induced autophagy in live Caenorhabditis elegans. Biomaterials 2015; 72:38-48. [PMID: 26342559 DOI: 10.1016/j.biomaterials.2015.08.044] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 08/25/2015] [Indexed: 12/31/2022]
Abstract
Autophagy is a highly important intracellular process for the degradation of endogenous or foreign contents in the cytoplasm. Though nanomaterials-induced autophagy has been extensively studied, real-time information about the autophagic process induced by nanomaterials in live organisms remains unknown. Here by using Caenorhabditis elegans as the model organism and fluorescent semiconductor quantum dots (QDs) as a representative nanomaterial, we systematically investigated the phenomenon of QDs-induced autophagy in live organisms. Our results demonstrated that the internalized QDs trigger a complete autophagic process in C. elegans intestinal cells. Further investigations revealed that this QD-induced autophagy in C. elegans is neither a response to released heavy metal ions by the QDs, nor an attempt to engulf exogenous QD materials, but a defensive strategy of the organism to clear and recycle damaged endosomes. Of particular significance, for the first time, we presented real-time tracking of autophagosomes formation in live organisms, providing detailed temporal-spatial information of this process. This study may help us better understand the relationship between nanomaterials and autophagy in vivo, and provide invaluable information for safety evaluation and bio-application of nanomaterials.
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Affiliation(s)
- Yanfeng Zhou
- Institute of Functional Nano & Soft Materials (FUNSOM), Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215123, China; Institutes of Biology and Medical Sciences (IBMS), Soochow University, Suzhou 215123, China
| | - Qin Wang
- Institute of Functional Nano & Soft Materials (FUNSOM), Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215123, China; Institutes of Biology and Medical Sciences (IBMS), Soochow University, Suzhou 215123, China
| | - Bin Song
- Institute of Functional Nano & Soft Materials (FUNSOM), Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215123, China
| | - Sicong Wu
- Institute of Functional Nano & Soft Materials (FUNSOM), Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215123, China
| | - Yuanyuan Su
- Institute of Functional Nano & Soft Materials (FUNSOM), Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215123, China
| | - Huimin Zhang
- Institutes of Biology and Medical Sciences (IBMS), Soochow University, Suzhou 215123, China.
| | - Yao He
- Institute of Functional Nano & Soft Materials (FUNSOM), Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215123, China.
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Serum- and Glucocorticoid-Inducible Kinase-1 (SGK-1) Plays a Role in Membrane Trafficking in Caenorhabditis elegans. PLoS One 2015; 10:e0130778. [PMID: 26115433 PMCID: PMC4482599 DOI: 10.1371/journal.pone.0130778] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 05/22/2015] [Indexed: 02/03/2023] Open
Abstract
The mammalian serum- and glucocorticoid-inducible kinase SGK1 regulates the endocytosis of ion channels. Here we report that in C. elegans sgk-1 null mutants, GFP-tagged MIG-14/Wntless, the sorting receptor of Wnt, failed to localize to the basolateral membrane of intestinal cells; instead, it was mis-sorted to lysosomes. This effect can be explained in part by altered sphingolipid levels, because reducing glucosylceramide biosynthesis restored the localization of MIG-14::GFP. Membrane traffic was not perturbed in general, as no obvious morphological defects were detected for early endosomes, the Golgi apparatus, and the endoplasmic reticulum (ER) in sgk-1 null animals. The recycling of MIG-14/Wntless through the Golgi might be partially responsible for the observed phenotype because the subcellular distribution of two plasma membrane cargoes that do not recycle through the trans-Golgi network (TGN) was affected to a lesser degree. Consistently, knockdown of the ArfGEF gbf-1 altered the distribution of SGK-1 at the basolateral membrane of intestinal cells. In addition, we found that sgk-1(RNAi) induced unfolded protein response in the ER, suggesting at least an indirect role of SGK-1 early in the secretory pathway. We propose that SGK-1 function is required for lipid homeostasis and that it acts at different intracellular trafficking steps.
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Panatala R, Hennrich H, Holthuis JCM. Inner workings and biological impact of phospholipid flippases. J Cell Sci 2015; 128:2021-32. [PMID: 25918123 DOI: 10.1242/jcs.102715] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The plasma membrane, trans-Golgi network and endosomal system of eukaryotic cells are populated with flippases that hydrolyze ATP to help establish asymmetric phospholipid distributions across the bilayer. Upholding phospholipid asymmetry is vital to a host of cellular processes, including membrane homeostasis, vesicle biogenesis, cell signaling, morphogenesis and migration. Consequently, defining the identity of flippases and their biological impact has been the subject of intense investigations. Recent work has revealed a remarkable degree of kinship between flippases and cation pumps. In this Commentary, we review emerging insights into how flippases work, how their activity is controlled according to cellular demands, and how disrupting flippase activity causes system failure of membrane function, culminating in membrane trafficking defects, aberrant signaling and disease.
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Affiliation(s)
- Radhakrishnan Panatala
- Department of Membrane Enzymology, Bijvoet Center and Institute of Biomembranes, Utrecht University, 3584 Utrecht, The Netherlands Molecular Cell Biology Division, University of Osnabrück, 49076 Osnabrück, Germany
| | - Hanka Hennrich
- Department of Membrane Enzymology, Bijvoet Center and Institute of Biomembranes, Utrecht University, 3584 Utrecht, The Netherlands
| | - Joost C M Holthuis
- Department of Membrane Enzymology, Bijvoet Center and Institute of Biomembranes, Utrecht University, 3584 Utrecht, The Netherlands Molecular Cell Biology Division, University of Osnabrück, 49076 Osnabrück, Germany
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