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Hirata E, Sakata KT, Dearden GI, Menon I, Chiduza GN, Menon AK. Molecular characterization of Rft1, a membrane protein associated with congenital disorder of glycosylation type 1N. bioRxiv 2024:2024.04.03.587922. [PMID: 38617304 PMCID: PMC11014557 DOI: 10.1101/2024.04.03.587922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
The oligosaccharide needed for protein N-glycosylation is assembled on a lipid carrier via a multi-step pathway. Synthesis is initiated on the cytoplasmic face of the endoplasmic reticulum (ER) and completed on the luminal side after transbilayer translocation of a heptasaccharide lipid intermediate. More than 30 Congenital Disorders of Glycosylation (CDGs) are associated with this pathway, including CDG 1N which results from defects in the membrane protein Rft1. Rft1 is essential for the viability of yeast and mammalian cells and was proposed as the transporter needed to flip the heptasaccharide lipid intermediate across the ER membrane. However, other studies indicated that Rft1 is not required for heptasaccharide lipid flipping in microsomes or unilamellar vesicles reconstituted with ER membrane proteins, nor is it required for the viability of at least one eukaryote. It is therefore not known what role Rft1 plays in N-glycosylation. Here, we present a molecular characterization of human Rft1, using yeast cells as a reporter system. We show that it is a multi-spanning membrane protein located in the ER, with its N and C-termini facing the cytoplasm. It is not N-glycosylated. The majority of CDG 1N mutations map to highly conserved regions of the protein. We identify key residues that are important for Rft1's ability to support glycosylation and cell viability. Our results provide a necessary platform for future work on this enigmatic protein.
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Affiliation(s)
- Eri Hirata
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
| | - Ken-taro Sakata
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
| | - Grace I. Dearden
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
| | - Indu Menon
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
| | - George N. Chiduza
- Structure and Function of Biological Membranes - Chemistry Department, Université Libre de Bruxelles - Campus Plaine, 1050 Brussels, Belgium
| | - Anant K. Menon
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
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Tsuji T. Subcellular distribution of membrane lipids revealed by freeze-fracture electron microscopy. Anat Sci Int 2024; 99:1-6. [PMID: 37314684 DOI: 10.1007/s12565-023-00731-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 05/30/2023] [Indexed: 06/15/2023]
Abstract
Cell membranes are composed of a large variety of lipids and proteins. While the localization and function of membrane proteins have been extensively investigated, the distribution of membrane lipids, especially in the non-cytoplasmic leaflet of organelle membranes, remains largely unknown. Fluorescent biosensors have been widely used to study membrane lipid distribution; however, they have some limitations. By utilizing the quick-freezing and freeze-fracture replica labeling electron microscopy technique, we can uncover the precise distribution of membrane lipids within cells and assess the function of lipid-transporting proteins. In this review, I summarize recent progress in analyzing intracellular lipid distribution by utilizing this method.
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Affiliation(s)
- Takuma Tsuji
- Laboratory of Molecular Cell Biology, Research Institute for Diseases of Old Age, Juntendo University Graduate School of Medicine, Tokyo, 113-8421, Japan.
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Cao SY, Liu YS, Gao XD, Kinoshita T, Fujita M. A lipid scramblase TMEM41B is involved in the processing and transport of GPI-anchored proteins. J Biochem 2023:7190350. [PMID: 37279648 DOI: 10.1093/jb/mvad041] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 04/27/2023] [Indexed: 06/08/2023] Open
Abstract
Protein modification by glycosylphosphatidylinositol (GPI) takes place in the endoplasmic reticulum (ER). GPI-anchored proteins (GPI-APs) formed in the ER are transported to the cell surface through the Golgi apparatus. During transport, the GPI-anchor structure is processed. In most cells, an acyl chain modified to the inositol of GPI is removed by a GPI-inositol deacylase, PGAP1, in the ER. Inositol-deacylated GPI-APs become sensitive to bacterial phosphatidylinositol-specific phospholipase C (PI-PLC). We previously reported that GPI-APs are partially resistant to PI-PLC when PGAP1 activity is weakened by the deletion of selenoprotein T (SELT) or cleft lip and palate transmembrane protein 1 (CLPTM1). In this study, we found that the loss of TMEM41B, an ER-localized lipid scramblase, restored PI-PLC sensitivity of GPI-APs in SELT-knockout (KO) and CLPTM1-KO cells. In TMEM41B-KO cells, the transport of GPI-APs as well as transmembrane proteins from the ER to the Golgi was delayed. Furthermore, the turnover of PGAP1, which is mediated by ER-associated degradation, was slowed in TMEM41B-KO cells. Taken together, these findings indicate that inhibition of TMEM41B-dependent lipid scrambling promotes GPI-AP processing in the ER through PGAP1 stabilization and slowed protein trafficking.
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Affiliation(s)
- Shu-Ya Cao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Yi-Shi Liu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Xiao-Dong Gao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Taroh Kinoshita
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
- WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan
| | - Morihisa Fujita
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China
- Institute for Glyco-core Research (iGCORE), Gifu University, Gifu 501-1193, Japan
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Holthuis JCM, Jahn H, Menon AK, Mizushima N. An alliance between lipid transfer proteins and scramblases for membrane expansion. Fac Rev 2022; 11:22. [PMID: 36081427 PMCID: PMC9397520 DOI: 10.12703/r-01-0000015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Membrane growth requires lipid supply, which is usually accomplished by lipid synthesis or vesicular trafficking. In the case of autophagosomes, these principles do not apply. Ghanbarpour et al. postulate that autophagosome expansion relies on non-vesicular lipid delivery from the ER, whereby the activity of a lipid transfer protein (LTP) is directly coupled to scramblase activities in the donor and acceptor bilayers1. This new concept opens the possibility that lipid traffic is controlled by scramblases that provide not only specific docking sites for LTPs, thereby directing lipid flow, but also support their activity by overcoming barriers for lipid extraction and deposition.
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Dai Z, Wang Q, Tang J, Wu M, Li H, Yang Y, Zhen X, Yu C. Immune-regulating bimetallic metal-organic framework nanoparticles designed for cancer immunotherapy. Biomaterials 2021; 280:121261. [PMID: 34815099 DOI: 10.1016/j.biomaterials.2021.121261] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 11/10/2021] [Accepted: 11/14/2021] [Indexed: 12/12/2022]
Abstract
Immunogenic cell death (ICD) is a promising strategy in cancer immunotherapy to induce high immunogenicity and activate the immune system. However, its efficacy is counteracted by the concurrent exposure of phosphatidylserine (PS), an immunosuppressive signal on the surface of cancer cells. Here we report the synthesis of a bimetallic metal-organic framework (MOF) nanoparticle containing Gd3+ and Zn2+ (Gd-MOF-5) that can be used as an immunomodulator to downregulate the immunosuppressive PS signal and an ICD inducer to upregulate immunostimulatory signals. Gd3+ inhibits PS externalization via inhibiting the activity of scramblase, an enzyme to transfer PS to the outer leaflet of plasma membrane. Moreover, intracellular Zn2+ overload activates endoplasmic reticulum stress for ICD induction. In combination with an immune checkpoint inhibitor (PD-L1 antibody, denoted as aPDL1), Gd-MOF-5 activated potent immune response and effectively inhibited primary and distal tumor growth in a bilateral 4T1 tumor model. This work presents a new strategy using designed MOF materials to modulate the cell signalling and immunosuppressive microenvironment to improve the outcome of cancer immunotherapy.
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Affiliation(s)
- Zan Dai
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, Brisbane, QLD, 4072, Australia
| | - Qiaoyun Wang
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, Brisbane, QLD, 4072, Australia
| | - Jie Tang
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, Brisbane, QLD, 4072, Australia
| | - Min Wu
- MOE Key Laboratory of High Performance Polymer Materials and Technology, Department of Polymer Science & Engineering, College of Chemistry & Chemical Engineering, Nanjing University, Nanjing, 210093, PR China
| | - Haoze Li
- MOE Key Laboratory of High Performance Polymer Materials and Technology, Department of Polymer Science & Engineering, College of Chemistry & Chemical Engineering, Nanjing University, Nanjing, 210093, PR China
| | - Yannan Yang
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, Brisbane, QLD, 4072, Australia
| | - Xu Zhen
- MOE Key Laboratory of High Performance Polymer Materials and Technology, Department of Polymer Science & Engineering, College of Chemistry & Chemical Engineering, Nanjing University, Nanjing, 210093, PR China.
| | - Chengzhong Yu
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, Brisbane, QLD, 4072, Australia; School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200241, PR China.
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Pereira-Martins DA, Coelho-Silva JL, Domingos IF, Weinhäuser I, Franca-Neto PL, Araujo AS, Franca RF, Bezerra MA, Lucena-Araujo AR. The ratio of ATP11C/PLSCR1 mRNA transcripts has clinical significance in sickle cell anemia. Ann Hematol 2021; 101:281-287. [PMID: 34651249 DOI: 10.1007/s00277-021-04696-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 10/10/2021] [Indexed: 11/27/2022]
Abstract
One of the physiologic mechanisms responsible to maintain asymmetric phospholipid distribution (in particular phosphatidylserine, PS) in human erythrocyte membranes is orchestrated by the balance between enzymes responsible for active transport of PS from the outer to the inner leaflet (ATP11C) and those whose counteracts these activities (PLSCR1). Using quantitative real-time polymerase chain reaction and standard flow cytometry procedures, we hypothesized that the aberrant expression of either or both ATP11C and PLSCR1 transcripts may disrupt the PS internalization/externalization process and become clinically relevant for patients with sickle cell anemia (SCA). Overall, neither ATP11C/PLSCR1 ratio or ATP11C and PLSCR1 (if analyzed separately) had impact on risk to present acute or chronic organ damage in 178 patients with SCA. By collecting a new set of samples from SCA patients during a vaso-occlusive crisis (VOC, crisis state, 13 patients) and comparing with new samples of patients in steady state (15 patients), we noticed that patients in steady state exhibited mean values of ATP11C/PLSCR1 ratio significantly higher (mean value: 18.2, range, 0.3-53) than those who were in crisis (mean value: 3.7, range, 0.5-9) (P = 0.013). Most importantly, there was a strong inverse correlation between PS exposure and ATP11C/PLSCR1 ratio in sickle erythrocytes (Pearson correlation coefficient, r: - 0.78). Based on these findings, it is conceivable that the ATP11C/PLSCR1 ratio may switch from high to low during a VOC, although the underlying reasons require further investigations.
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Affiliation(s)
- Diego A Pereira-Martins
- Department of Genetics, Federal University of Pernambuco, Av. Prof. Moraes Rego, 1235, Recife, PE, 50670-901, Brazil
- Department of Internal Medicine, Medical School of Ribeirao Preto and Centre for Cell-Based Therapy, University of São Paulo, Ribeirao Preto, SP, 14051140, Brazil
| | - Juan L Coelho-Silva
- Department of Genetics, Federal University of Pernambuco, Av. Prof. Moraes Rego, 1235, Recife, PE, 50670-901, Brazil
| | - Igor F Domingos
- Department of Genetics, Federal University of Pernambuco, Av. Prof. Moraes Rego, 1235, Recife, PE, 50670-901, Brazil
| | - Isabel Weinhäuser
- Department of Internal Medicine, Medical School of Ribeirao Preto and Centre for Cell-Based Therapy, University of São Paulo, Ribeirao Preto, SP, 14051140, Brazil
| | - Pedro L Franca-Neto
- Department of Genetics, Federal University of Pernambuco, Av. Prof. Moraes Rego, 1235, Recife, PE, 50670-901, Brazil
| | - Aderson S Araujo
- Department of Internal Medicine, Hematology and Hemotherapy Foundation of Pernambuco, Recife, PE, 52011-000, Brazil
| | - Rafael F Franca
- Department of Virology, Aggeu Magalhães Institute/Oswaldo Cruz Foundation, Recife, PE, 50670-901, Brazil
| | - Marcos A Bezerra
- Department of Genetics, Federal University of Pernambuco, Av. Prof. Moraes Rego, 1235, Recife, PE, 50670-901, Brazil
| | - Antonio R Lucena-Araujo
- Department of Genetics, Federal University of Pernambuco, Av. Prof. Moraes Rego, 1235, Recife, PE, 50670-901, Brazil.
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Danek A. "Huntington disease-like phenotype in a patient with ANO3 mutation" Expert commentary. Parkinsonism Relat Disord 2021; 90:123-124. [PMID: 34281767 DOI: 10.1016/j.parkreldis.2021.07.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 07/06/2021] [Accepted: 07/07/2021] [Indexed: 11/20/2022]
Affiliation(s)
- Adrian Danek
- University Hospital, LMU Munich, Department of Neurology, Marchioninistr. 15, 81377, München, Germany.
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Noda NN. Atg2 and Atg9: Intermembrane and interleaflet lipid transporters driving autophagy. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:158956. [PMID: 33932584 DOI: 10.1016/j.bbalip.2021.158956] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 04/03/2021] [Accepted: 04/08/2021] [Indexed: 12/14/2022]
Abstract
Autophagy, an intracellular degradation mechanism, involves de novo generation of autophagosomes that sequester and deliver cytoplasmic components to the lysosome for degradation. The mechanism behind autophagosomal membrane expansion has been a longstanding enigma in this field. Recent structural and biochemical analyses have revealed that two mysterious autophagy-related (Atg) proteins, Atg2 and Atg9, are novel types of intermembrane and interleaflet lipid transporters, respectively. This review summarizes recent discoveries surrounding Atg2 and Atg9 as a lipid transporter and discusses the molecular mechanism of autophagosomal membrane expansion driven by collaboration between these two lipid transporters.
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Abstract
Phospholipids are asymmetrically distributed at the plasma membrane. Phosphatidylserine (PtdSer) is exclusively located in the inner leaflet of the cell membrane while phosphatidylcholine (PtdCho) and glycolipids are mainly located in the outer leaflet of the membrane. However, this asymmetry is disrupted in various physiological situations, and PtdSer is exposed on the cell surface. In platelets, exposed PtdSer functions as a scaffold for the coagulation reaction, while in dead cells, exposed PtdSer serves as an "Eat-me" signal for efferocytosis. In the developing brain, synaptic connections are over-formed during the fetal period, but about half of the neurons are removed by apoptosis, and synaptic and dendritic compartments of living neurons are also removed by phagocytes. During these processes, glial cells such as microglia and astrocyte engulf unwanted dead cells and compartments in living cells using several phagocytic receptors, recognizing PtdSer by direct binding or an indirect way using secreted molecules. Based on recent findings, we will discuss how the compartments in living neurons are eliminated for the neuronal circuit plasticity.
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Abstract
The TMEM16 protein family comprises two novel classes of structurally conserved but functionally distinct membrane transporters that function as Ca2+-dependent Cl- channels (CaCCs) or dual functional Ca2+-dependent ion channels and phospholipid scramblases. Extensive functional and structural studies have advanced our understanding of TMEM16 molecular mechanisms and physiological functions. TMEM16A and TMEM16B CaCCs control transepithelial fluid transport, smooth muscle contraction, and neuronal excitability, whereas TMEM16 phospholipid scramblases mediate the flip-flop of phospholipids across the membrane to allow phosphatidylserine externalization, which is essential in a plethora of important processes such as blood coagulation, bone development, and viral and cell fusion. In this chapter, we summarize the major methods in studying TMEM16 ion channels and scramblases and then focus on the current mechanistic understanding of TMEM16 Ca2+- and voltage-dependent channel gating as well as their ion and phospholipid permeation.
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Affiliation(s)
- Son C Le
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
| | - Huanghe Yang
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA.
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Abstract
Phosphatidylserine (PtdSer), an essential constituent of eukaryotic membranes, is the most abundant anionic phospholipid in the eukaryotic cell accounting for up to 10% of the total cellular lipid. Much of what is known about PtdSer is the role exofacial PtdSer plays in apoptosis and blood clotting. However, PtdSer is generally not externally exposed in healthy cells and plays a vital role in several intracellular signaling pathways, though relatively little is known about the precise subcellular localization, transmembrane topology and intracellular dynamics of PtdSer within the cell. The recent development of new, genetically-encoded probes able to detect phosphatidylserine is leading to a more in-depth understanding of the biology of this phospholipid. This review aims to give an overview of recent developments in our understanding of the role of PtdSer in intracellular signaling events derived from the use of these recently developed methods of phosphatidylserine detection.
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Affiliation(s)
- Jason G Kay
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, Buffalo, NY, 14214, USA.
| | - Gregory D Fairn
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, M5B 1W8, Canada. .,Department of Surgery, University of Toronto, Toronto, ON, M5S 1A8, Canada. .,Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada.
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Chowdhury KD, Sarkar A, Chatterjee S, Patra D, Sengupta D, Banerjee S, Chakraborty P, Sadhukhan GC. Cathepsin B mediated scramblase activation triggers cytotoxicity and cell cycle arrest by andrographolide to overcome cellular resistance in cisplatin resistant human hepatocellular carcinoma HepG2 cells. Environ Toxicol Pharmacol 2019; 68:120-132. [PMID: 30889542 DOI: 10.1016/j.etap.2019.03.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Revised: 10/24/2018] [Accepted: 03/03/2019] [Indexed: 06/09/2023]
Abstract
Andrographolide regimen in single or in combination with anticancer drugs is a promising new strategy to reverse chemoresistance in heaptocellular carcinoma. Apoptosis inducing factor (AIF) may regulate a complementary, cooperative or redundant pathway, along with caspase cascades. Despite these findings, mechanisms underlying caspase-dependent and-independent signaling pathways in andrographolide -induced apoptosis in cisplatin-resistant human hepatocellular carcinoma cell line (HepG2CR) remain unclear. Andrographolide treatment effectively reduced NF-κβ nuclear localization by modulating protein kinase A- protein phosphatase 2 A- Iκβ kinase (PKA/PP2 A/IKK) axis that in turn maintains initiator caspase8 activity. Lysosomal distribution of tBid stimulates cytosolic cathepsin B resulting accumulation of truncated-AIF with induction in scramblase mediated phosphatidylserine exposure in HepG2CR cells. Andrographolide treatment thereby switch on subG1 phase arrest by modulating cellular check points (cyclin A, B, cyclin dependent kinase-1) cueing to the apoptosis event. Collectively, this study suggested antineoplastic potential of andrographolide through PKA/PP2 A/IKK pathway in HepG2CR cells.
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Affiliation(s)
- Kaustav Dutta Chowdhury
- Cyto-genetics Laboratory, Department of Zoology, Rammohan College, 102/1, Raja Rammohan Sarani, Kolkata, 700 009, India
| | - Avik Sarkar
- Department of Molecular Biology and Bioinformatics, Tripura University, India
| | - Sujan Chatterjee
- Molecular Biology and Tissue Culture Laboratory, Post Graduate Department of Zoology, Vidyasagar College, Kolkata, 700006, India
| | - Debajyoti Patra
- Molecular Biology and Tissue Culture Laboratory, Post Graduate Department of Zoology, Vidyasagar College, Kolkata, 700006, India
| | | | - Soumi Banerjee
- Cyto-genetics Laboratory, Department of Zoology, Rammohan College, 102/1, Raja Rammohan Sarani, Kolkata, 700 009, India
| | - Pratip Chakraborty
- Department of Infertility, Institute of Reproductive Medicine, HB-36/A/3, Salt Lake, Sector-III, Kolkata, 700106, India
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Veit M, Koyro KI, Ahrens B, Bleibaum F, Munz M, Rövekamp H, Andrä J, Schreiber R, Kunzelmann K, Sommer A, Bhakdi S, Reiss K. Anoctamin-6 regulates ADAM sheddase function. Biochim Biophys Acta Mol Cell Res 2018; 1865:1598-1610. [PMID: 30327201 DOI: 10.1016/j.bbamcr.2018.08.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 08/17/2018] [Accepted: 08/20/2018] [Indexed: 02/07/2023]
Abstract
ADAM17, a prominent member of the "Disintegrin and Metalloproteinase" (ADAM) family, controls vital cellular functions through cleavage of transmembrane substrates including TGF-alpha, Amphiregulin (AREG) and TNF-Receptor 1 (TNFR1). We recently presented evidence that surface exposure of phosphatidylserine (PS) is pivotal for ADAM17 to exert sheddase activity. Anoctamin-6 (ANO6) has Ca2+-dependent phospholipid scramblase activity and it followed that the functions of ANO6 and ADAM17 might be linked. We report that overexpression of ANO6 in HEK293T cells led to increased Ca2+-mediated PS-exposure that was indeed accompanied by enhanced release of AREG and TGF-alpha. The effect was not observed when cells were treated with the PKC-dependent ADAM17 activator PMA. Transformation of cells with a constitutively active ANO6 mutant led to spontaneous PS-exposure and to the release of ADAM17-substrates in the absence of any stimuli. Inhibitor experiments indicated that ANO6-mediated enhancement of substrate cleavage simultaneously broadened the spectrum of participating metalloproteinases. In complementary experiments, siRNA-mediated downregulation of ANO6 was shown to decrease ionophore-mediated release of TNFR1 in human umbilical vein endothelial cells (HUVECs). We conclude that ANO6, by virtue of its scramblase activity, may play a role as an important regulator of the ADAM-network in the plasma membrane.
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Affiliation(s)
- Martin Veit
- Dept. of Dermatology, University of Kiel, 24105 Kiel, Germany
| | | | - Björn Ahrens
- Dept. of Dermatology, University of Kiel, 24105 Kiel, Germany
| | | | - Martin Munz
- Dept. of Dermatology, University of Kiel, 24105 Kiel, Germany
| | - Hagen Rövekamp
- Dept. of Dermatology, University of Kiel, 24105 Kiel, Germany
| | - Jörg Andrä
- Hamburg University of Applied Science, Ulmenliet 20, 21033 Hamburg, Germany
| | - Rainer Schreiber
- Physiological Institute, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Karl Kunzelmann
- Physiological Institute, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Anselm Sommer
- Dept. of Dermatology, University of Kiel, 24105 Kiel, Germany
| | - Sucharit Bhakdi
- Dept. of Dermatology, University of Kiel, 24105 Kiel, Germany
| | - Karina Reiss
- Dept. of Dermatology, University of Kiel, 24105 Kiel, Germany.
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Cotton RJ, Ploier B, Goren MA, Menon AK, Graumann J. flippant-An R package for the automated analysis of fluorescence-based scramblase assays. BMC Bioinformatics 2017; 18:146. [PMID: 28253836 PMCID: PMC5335725 DOI: 10.1186/s12859-017-1542-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 02/08/2017] [Indexed: 11/30/2022] Open
Abstract
Background The lipid scrambling activity of protein extracts and purified scramblases is typically measured using a fluorescence-based assay. While the assay has yielded insight into the scramblase activity in crude membrane preparations, functional validation of candidate scramblases, stoichiometry of scramblase complexes as well as ATP-dependence of flippases, data analysis in its context has remained a task involving many manual steps. Results With the extension package “flippant” to R, a free software environment for statistical computing and graphics, we introduce an integrated solution for the analysis and publication-grade graphical presentation of dithionite scramblase assays and demonstrate its utility in revisiting an originally manual analysis from the publication record, closely reproducing the reported results. Conclusions “flippant” allows for quick, reproducible data analysis of scramblase activity assays and provides a platform for review, dissemination and extension of the strategies it employs. Electronic supplementary material The online version of this article (doi:10.1186/s12859-017-1542-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Richard J Cotton
- Research Division, Weill Cornell Medicine-Qatar, P.O.Box 24144, Doha, State of Qatar
| | - Birgit Ploier
- Department of Biochemistry, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Michael A Goren
- Department of Biochemistry, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Anant K Menon
- Department of Biochemistry, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Johannes Graumann
- Research Division, Weill Cornell Medicine-Qatar, P.O.Box 24144, Doha, State of Qatar. .,Current Address: Scientific Service Group Biomolecular Mass Spectrometry, Max Planck Institute for Heart and Lung Research, W.G. Kerckhoff Institute, Ludwigstr. 43, D-61231, Bad Nauheim, Germany.
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Andraka N, Sánchez-Magraner L, García-Pacios M, Goñi FM, Arrondo JLR. The conformation of human phospholipid scramblase 1, as studied by infrared spectroscopy. Effects of calcium and detergent. Biochim Biophys Acta Biomembr 2017; 1859:1019-1028. [PMID: 28238818 DOI: 10.1016/j.bbamem.2017.02.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 02/18/2017] [Accepted: 02/22/2017] [Indexed: 12/18/2022]
Abstract
Human phospholipid scramblase 1 (SCR) is a membrane protein that catalyzes the transmembrane (flip-flop) motion of phospholipids. It can also exist in a non membrane-bound form in the nucleus, where it modulates several aspects of gene expression. Catalysis of phospholipid flip-flop requires the presence of millimolar Ca2+, and occurs in the absence of ATP. Membrane-bound SCR contains a C-terminal α-helical domain embedded in the membrane bilayer. The latter domain can be removed giving rise to a stable truncated mutant SCRΔ that is devoid of scramblase activity. In order to improve our understanding of SCR structure infrared spectra have been recorded of both the native and truncated forms, and the effects of adding Ca2+, or removing detergent, or thermally denaturing the protein have been observed. Under all conditions the main structural component of SCR/SCRΔ is a β-sheet. Removing the C-terminal 28 aa residues, which anchor SCR to the membrane, leads to a change in tertiary structure and an increased structural flexibility. The main effect of Ca2+ is an increase in the α/β ratio of secondary structure components, with a concomitant increase in the proportion of non-periodic structures. At least in SCRΔ, detergent (Zwittergent 3-12) decreases the structural flexibility, an effect somewhat opposite to that of increasing temperature. Thermal denaturation is affected by Ca2+, detergent, and by the presence or absence of the C-terminal domain, each of them influencing in different ways the denaturation pattern.
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Affiliation(s)
- Nagore Andraka
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, P.O. Box 644, 48080 Bilbao, Spain
| | - Lissete Sánchez-Magraner
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, P.O. Box 644, 48080 Bilbao, Spain
| | - Marcos García-Pacios
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, P.O. Box 644, 48080 Bilbao, Spain
| | - Félix M Goñi
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, P.O. Box 644, 48080 Bilbao, Spain
| | - José L R Arrondo
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, P.O. Box 644, 48080 Bilbao, Spain.
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16
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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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17
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Sivagnanam U, Narayana Murthy S, Gummadi SN. Identification and characterization of the novel nuclease activity of human phospholipid scramblase 1. BMC Biochem 2016; 17:10. [PMID: 27206388 PMCID: PMC4875679 DOI: 10.1186/s12858-016-0067-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 05/17/2016] [Indexed: 01/05/2023]
Abstract
Background Human phospholipid scramblase 1 (hPLSCR1) was initially identified as a Ca2+ dependent phospholipid translocator involved in disrupting membrane asymmetry. Recent reports revealed that hPLSCR1 acts as a multifunctional signaling molecule rather than functioning as scramblase. hPLSCR1 is overexpressed in a variety of tumor cells and is known to interact with a number of protein molecules implying diverse functions. Results In this study, the nuclease activity of recombinant hPLSCR1 and its biochemical properties have been determined. Point mutations were generated to identify the critical region responsible for the nuclease activity. Recombinant hPLSCR1 exhibits Mg2+ dependent nuclease activity with an optimum pH and temperature of 8.5 and 37 °C respectively. Experiments with amino acid modifying reagents revealed that histidine, cysteine and arginine residues were crucial for its function. hPLSCR1 has five histidine residues and point mutations of histidine residues to alanine in hPLSCR1 resulted in 60 % loss in nuclease activity. Thus histidine residues could play a critical role in the nuclease activity of hPLSCR1. Conclusions This is the first report on the novel nuclease activity of the multi-functional hPLSCR1. hPLSCR1 shows a metal dependent nuclease activity which could play a role in key cellular processes that needs to be further investigated.
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Affiliation(s)
- Ulaganathan Sivagnanam
- From the Applied and Industrial Microbiology Laboratory, Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, 600 036, India
| | - Shweta Narayana Murthy
- From the Applied and Industrial Microbiology Laboratory, Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, 600 036, India
| | - Sathyanarayana N Gummadi
- From the Applied and Industrial Microbiology Laboratory, Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, 600 036, India.
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18
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Chauhan N, Farine L, Pandey K, Menon AK, Bütikofer P. Lipid topogenesis--35years on. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:757-766. [PMID: 26946259 DOI: 10.1016/j.bbalip.2016.02.025] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 02/24/2016] [Accepted: 02/25/2016] [Indexed: 12/28/2022]
Abstract
Glycerophospholipids are the principal fabric of cellular membranes. The pathways by which these lipids are synthesized were elucidated mainly through the work of Kennedy and colleagues in the late 1950s and early 1960s. Subsequently, attention turned to cell biological aspects of lipids: Where in the cell are lipids synthesized? How are lipids integrated into membranes to form a bilayer? How are they sorted and transported from their site of synthesis to other cellular destinations? These topics, collectively termed 'lipid topogenesis', were the subject of a review article in 1981 by Bell, Ballas and Coleman. We now assess what has been learned about early events of lipid topogenesis, i.e. "lipid synthesis, the integration of lipids into membranes, and lipid translocation across membranes", in the 35 years since the publication of this important review. We highlight the recent elucidation of the X-ray structures of key membrane enzymes of glycerophospholipid synthesis, progress on identifying lipid scramblase proteins needed to equilibrate lipids across membranes, and new complexities in the subcellular location and membrane topology of phosphatidylinositol synthesis revealed through a comparison of two unicellular model eukaryotes. 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)
- Neha Chauhan
- Department of Biochemistry, Weill Cornell Medical College, New York 10065, USA
| | - Luce Farine
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
| | - Kalpana Pandey
- Department of Biochemistry, Weill Cornell Medical College, New York 10065, USA
| | - Anant K Menon
- Department of Biochemistry, Weill Cornell Medical College, New York 10065, USA.
| | - Peter Bütikofer
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland.
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Abstract
Ca2+-activated Cl− channels (CaCCs) are a class of Cl− channels activated by intracellular Ca2+ that are known to mediate numerous physiological functions. In 2008, the molecular identity of CaCCs was found to be anoctamin 1 (ANO1/TMEM16A). Its roles have been studied in electrophysiological, histological, and genetic aspects. ANO1 is known to mediate Cl− secretion in secretory epithelia such as airways, salivary glands, intestines, renal tubules, and sweat glands. ANO1 is a heat sensor activated by noxious heat in somatosensory neurons and mediates acute pain sensation as well as chronic pain. ANO1 is also observed in vascular as well as airway smooth muscles, controlling vascular tone as well as airway hypersensitivity. ANO1 is upregulated in numerous types of cancers and thus thought to be involved in tumorigenesis. ANO1 is also found in proliferating cells. In addition to ANO1, involvement of its paralogs in pathophysiological conditions was also reported. ANO2 is involved in olfaction, whereas ANO6 works as a scramblase whose mutation causes a rare bleeding disorder, the Scott syndrome. ANO5 is associated with muscle and bone diseases. Recently, an X-ray crystal structure of a fungal TMEM16 was reported, which explains a precise molecular gating mechanism as well as ion conduction or phospholipid transport across the plasma membrane.
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Abstract
Phospholipids are asymmetrically distributed at plasma membrane in normal cells, and scrambled in various biological situations such as blood clotting and apoptotic cell death. Recent studies revealed that phospholipid scrambling is mediated by at least two independent mechanisms. An eight transmembrane-containing protein TMEM16F Ca(2+)-dependently promotes the phospholipid scrambling, which is required for the PS exposure in activated platelets during blood clotting. On the other hand, a six transmembrane-containing protein Xk-related family protein 8 is activated by caspases during apoptosis and promotes the phospholipid scrambling, thus exposing PS as an "eat-me-signal." In this chapter, we describe procedures for assaying phospholipid scrambling.
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Affiliation(s)
- Jun Suzuki
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Shigekazu Nagata
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
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21
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Abstract
Apoptotic cells expose phosphatidylserine (PtdSer) on their surface as an "eat me" signal. Mammalian Xk-related (Xkr) protein 8, which is predicted to contain six transmembrane regions, and its Caenorhabditis elegans homolog CED-8 promote apoptotic PtdSer exposure. The mouse and human Xkr families consist of eight and nine members, respectively. Here, we found that mouse Xkr family members, with the exception of Xkr2, are localized to the plasma membrane. When Xkr8-deficient cells, which do not expose PtdSer during apoptosis, were transformed by Xkr family members, the transformants expressing Xkr4, Xkr8, or Xkr9 responded to apoptotic stimuli by exposing cell surface PtdSer and were efficiently engulfed by macrophages. Like Xkr8, Xkr4 and Xkr9 were found to possess a caspase recognition site in the C-terminal region and to require its direct cleavage by caspases for their function. Site-directed mutagenesis of the amino acid residues conserved among CED-8, Xkr4, Xkr8, and Xkr9 identified several essential residues in the second transmembrane and second cytoplasmic regions. Real time PCR analysis indicated that unlike Xkr8, which is ubiquitously expressed, Xkr4 and Xkr9 expression is tissue-specific.
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Affiliation(s)
- Jun Suzuki
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Yoshida-Konoe, Sakyo-ku, Kyoto, Kyoto 606-8501, Japan
| | - Eiichi Imanishi
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Yoshida-Konoe, Sakyo-ku, Kyoto, Kyoto 606-8501, Japan
| | - Shigekazu Nagata
- Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Yoshida-Konoe, Sakyo-ku, Kyoto, Kyoto 606-8501, Japan.
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22
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Posada IM, Busto JV, Goñi FM, Alonso A. Membrane binding and insertion of the predicted transmembrane domain of human scramblase 1. Biochim Biophys Acta 2014; 1838:388-97. [PMID: 24099740 DOI: 10.1016/j.bbamem.2013.09.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 09/19/2013] [Accepted: 09/25/2013] [Indexed: 10/26/2022]
Abstract
Human phospholipid scramblase 1 (SCR) was originally described as an intrinsic membrane protein catalyzing transbilayer phospholipid transfer in the absence of ATP. More recently, a role as a nuclear transcription factor has been proposed for SCR, either in addition or alternatively to its capacity to facilitate phospholipid flip-flop. Uncertainties exist as well from the structural point of view. A predicted α-helix (aa residues 288-306) located near the C-terminus has been alternatively proposed as a transmembrane domain, or as a protein core structural element. This paper explores the possibilities of the above helical segment as a transmembrane domain. To this aim two peptides were synthesized, one corresponding to the 19 α-helical residues, and one containing both the helix and the subsequent 12-residues constituting the C-end of the protein. The interaction of these peptides with lipid monolayers and bilayers was tested with Langmuir balance surface pressure measurements, proteoliposome reconstitution and analysis, differential scanning calorimetry, tests of bilayer permeability, and fluorescence confocal microscopy. Bilayers of 28 different lipid compositions were examined in which lipid electric charge, bilayer fluidity and lateral heterogeneity (domain formation) were varied. All the results concur in supporting the idea that the 288-306 peptide of SCR becomes membrane inserted in the presence of lipid bilayers. Thus, the data are in agreement with the possibility of SCR as an integral membrane protein, without rejecting alternative cell locations.
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Key Words
- 1,1,1,3,3,3-hexafluoro-2-propanol
- 1,1′-dioctadecyl-3,3,3′,3′-tetramethyl-indodicarbocyanine
- 8-aminonaphtalene-1,3,6-trisulfonic acid sodium salt
- ANTS
- DID
- DPX
- GUVs
- HFIP
- LUVs
- Lipid phases
- MLVs
- PC
- PE
- PG
- PI
- PLSCR1
- PS
- SCR
- SCR 288–306 peptide
- SCR 288–318 peptide
- Scramblase
- TM
- TM19
- TM31C
- Transbilayer
- Transmembrane helix
- giant unilamellar vesicles
- human phospholipid scramblase 1, or hPLSCR1
- large unilamellar vesicles
- multilamellar vesicles
- p-xylene-bis(pyridinium) bromide
- pSM
- palmitoyl sphingomyelin
- phosphatidylcholine
- phosphatidylethanolamine
- phosphatidylglycerol
- phosphatidylinositol
- phosphatidylserine
- transmembrane
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