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Annexin-phospholipid interactions. Functional implications. Int J Mol Sci 2013; 14:2652-83. [PMID: 23358253 PMCID: PMC3588008 DOI: 10.3390/ijms14022652] [Citation(s) in RCA: 158] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Revised: 01/12/2013] [Accepted: 01/15/2013] [Indexed: 02/03/2023] Open
Abstract
Annexins constitute an evolutionary conserved multigene protein superfamily characterized by their ability to interact with biological membranes in a calcium dependent manner. They are expressed by all living organisms with the exception of certain unicellular organisms. The vertebrate annexin core is composed of four (eight in annexin A6) homologous domains of around 70 amino acids, with the overall shape of a slightly bent ring surrounding a central hydrophilic pore. Calcium- and phospholipid-binding sites are located on the convex side while the N-terminus links domains I and IV on the concave side. The N-terminus region shows great variability in length and amino acid sequence and it greatly influences protein stability and specific functions of annexins. These proteins interact mainly with acidic phospholipids, such as phosphatidylserine, but differences are found regarding their affinity for lipids and calcium requirements for the interaction. Annexins are involved in a wide range of intra- and extracellular biological processes in vitro, most of them directly related with the conserved ability to bind to phospholipid bilayers: membrane trafficking, membrane-cytoskeleton anchorage, ion channel activity and regulation, as well as antiinflammatory and anticoagulant activities. However, the in vivo physiological functions of annexins are just beginning to be established.
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Qiu X, Huang K, Liu Y, Zhang X, Gao Y. Cloning, expression, purification, crystallization and preliminary X-ray diffraction crystallographic study of human synaptotagmin 5 C2A domain. Acta Crystallogr Sect F Struct Biol Cryst Commun 2011; 67:1375-7. [PMID: 22102235 PMCID: PMC3212454 DOI: 10.1107/s1744309111032155] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Accepted: 08/08/2011] [Indexed: 11/10/2022]
Abstract
Synaptotagmin acts as the Ca(2+) sensor for neural and endocrine exocytosis. Synaptotagmin 5 has been demonstrated to play a key role in the acquisition of cathepsin D and the vesicular proton ATPase and in Ca(2+)-dependent insulin exocytosis. The C2 domains modulate the interaction of synaptotagmin with the phospholipid bilayer of the presynaptic terminus and effector proteins such as the SNARE complex. This study reports the cloning, expression in Escherichia coli, purification, crystallization and preliminary X-ray analysis of the C2A domain of human synaptotagmin 5 with an N-terminal His(6) tag. The crystals diffracted to 1.90 Å resolution and belonged to the hexagonal space group P6(5), with unit-cell parameters a = b = 93.97, c = 28.05 Å. A preliminary model of the protein structure has been built and refinement of the model is ongoing.
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Affiliation(s)
- Xiaoting Qiu
- Hefei National Laboratory for Physical Sciences at Microscale, School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, People’s Republic of China
- Key Laboratory of Structural Biology, Chinese Academy of Sciences, 96 Jinzhai Road, Hefei, Anhui 230026, People’s Republic of China
| | - Kai Huang
- Hefei National Laboratory for Physical Sciences at Microscale, School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, People’s Republic of China
- Key Laboratory of Structural Biology, Chinese Academy of Sciences, 96 Jinzhai Road, Hefei, Anhui 230026, People’s Republic of China
| | - Yiwei Liu
- Hefei National Laboratory for Physical Sciences at Microscale, School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, People’s Republic of China
- Key Laboratory of Structural Biology, Chinese Academy of Sciences, 96 Jinzhai Road, Hefei, Anhui 230026, People’s Republic of China
| | - Xiao Zhang
- Hefei National Laboratory for Physical Sciences at Microscale, School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, People’s Republic of China
- Key Laboratory of Structural Biology, Chinese Academy of Sciences, 96 Jinzhai Road, Hefei, Anhui 230026, People’s Republic of China
| | - Yongxiang Gao
- Hefei National Laboratory for Physical Sciences at Microscale, School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, People’s Republic of China
- Key Laboratory of Structural Biology, Chinese Academy of Sciences, 96 Jinzhai Road, Hefei, Anhui 230026, People’s Republic of China
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Montes M, Fuson KL, Sutton RB, Robert JJ. Purification, crystallization and X-ray diffraction analysis of human synaptotagmin 1 C2A-C2B. Acta Crystallogr Sect F Struct Biol Cryst Commun 2006; 62:926-9. [PMID: 16946482 PMCID: PMC2242877 DOI: 10.1107/s1744309106029253] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2006] [Accepted: 07/28/2006] [Indexed: 11/10/2022]
Abstract
Synaptotagmin acts as the Ca(2+) sensor for neuronal exocytosis. The cytosolic domain of human synaptotagmin 1 is composed of tandem C2 domains: C2A and C2B. These C2 domains modulate the interaction of synaptotagmin with the phospholipid bilayer of the presynaptic terminus and effector proteins such as the SNARE complex. Human synaptotagmin C2A-C2B has been expressed as a glutathione-S-transferase fusion protein in Escherichia coli. The purification, crystallization and preliminary X-ray analysis of this protein are reported here. The crystals diffract to 2.7 A and belong to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 82.37, b = 86.31, c = 140.2 A. From self-rotation function analysis, there are two molecules in the asymmetric unit. The structure determination of the protein using this data is ongoing.
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Affiliation(s)
- Miguel Montes
- Department of Neuroscience and Cell Biology, The University of Texas Medical Branch, Galveston, TX 77555-0437, USA
| | - Kerry L. Fuson
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, TX 77555-0437, USA
| | - R. Bryan Sutton
- Department of Neuroscience and Cell Biology, The University of Texas Medical Branch, Galveston, TX 77555-0437, USA
- Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, TX 77555-0437, USA
| | - J. Justin Robert
- Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, TX 77555-0437, USA
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Tsuboi T, Kikuta T, Sakurai T, Terakawa S. Water secretion associated with exocytosis in endocrine cells revealed by micro forcemetry and evanescent wave microscopy. Biophys J 2002; 83:172-83. [PMID: 12080110 PMCID: PMC1302137 DOI: 10.1016/s0006-3495(02)75159-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
It has been a long belief that release of substances from the cell to the extracellular milieu by exocytosis is completed by diffusion of the substances from secretory vesicles through the fusion pore. Involvement of any mechanical force that may be superposed on the diffusion to enhance the releasing process has not been elucidated to date. We tackled this problem in cultured bovine chromaffin cells using direct and sensitive methods: the laser-trap forcemetry and the evanescent-wave fluorescence microscopy. With a laser beam, we trapped a micro bead in the vicinity of a cell (with 1 microm of separation) and observed movements of the bead optically. Electrical stimulation of the cell induced many of rapid and transient movements of the bead in a direction away from the cell surface. Upon the same stimulation, secretory vesicles stained with a fluorescent probe, acridine orange, and excited under the evanescent field illumination, showed a flash-like response: a transient increase in fluorescence intensity associated with a diffuse cloud of brightness, followed by a complete disappearance. These mechanical and fluorescence transients indicate a directional flow of substances. Blockers of the Cl(-) channel suppressed the rates of both responses in a characteristic way but not exocytotic fusion itself. Immunocytochemical studies revealed the presence of Cl(-) and K(+) channels on the vesicle membranes. These results suggest that the externalization of hormones or transmitters upon exocytosis of vesicles is augmented by secretion of water from the vesicle membrane through the widened fusion pore, possibly modulating the rate and reach of the hormone or transmitter release and facilitating transport of the signal molecules in intercellular spaces.
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Affiliation(s)
- Takashi Tsuboi
- Photon Medical Research Center, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan
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Tritel M, Resh MD. The late stage of human immunodeficiency virus type 1 assembly is an energy-dependent process. J Virol 2001; 75:5473-81. [PMID: 11356954 PMCID: PMC114259 DOI: 10.1128/jvi.75.12.5473-5481.2001] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Several recent studies have indicated the involvement of host cell factors in human immunodeficiency virus type 1 (HIV-1) assembly. To ascertain whether ATP-dependent factors play a role in this process, we quantified virus-like particle (VLP) production by ATP-depleted cells. Pharmacological ATP depletion abrogated VLP production without affecting cell viability or inducing degradation of HIV-1 Gag protein. This effect occurred even when the ATP-depleting agents were added 1 h into the assembly process, and it was reversed by removal of these agents. ATP depletion did not affect Gag membrane binding or multimerization. Density gradient analysis indicated that HIV-1 assembly intermediates were stalled late in the assembly process. This conclusion was further supported by electron microscopy analysis, which revealed a preponderance of plasma membrane-associated stalk-like structures in the ATP-depleted cells. Since no HIV-1 proteins bind or hydrolyze ATP, these findings indicate that an ATP-requiring cellular factor is an obligatory participant late in the HIV-1 assembly process.
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Affiliation(s)
- M Tritel
- Cell Biology Program, Memorial Sloan-Kettering Cancer Center, and Graduate Program in Cell Biology and Genetics, Weill Graduate School of Medical Sciences of Cornell University, New York, New York 10021, USA
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Sutton RB, Ernst JA, Brunger AT. Crystal structure of the cytosolic C2A-C2B domains of synaptotagmin III. Implications for Ca(+2)-independent snare complex interaction. J Cell Biol 1999; 147:589-98. [PMID: 10545502 PMCID: PMC2151181 DOI: 10.1083/jcb.147.3.589] [Citation(s) in RCA: 156] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/1999] [Accepted: 09/30/1999] [Indexed: 11/22/2022] Open
Abstract
Synaptotagmins are synaptic vesicle-associated, phospholipid-binding proteins most commonly associated with Ca(+2)-dependent exocytotic and Ca(+2)- independent endocytotic events. Synaptotagmin III is a 63.2-kD member of the synaptotagmin homology group; one of its characteristic properties is the ability to bind divalent cations and accessory proteins promiscuously. In the cytosolic portion of this protein, a flexible seven-amino acid linker joins two homologous C2 domains. The C2A domain binds to phospholipid membranes and other accessory proteins in a divalent cation-dependent fashion. The C2B domain promotes binding to other C2B domains, as well as accessory proteins independent of divalent cations. The 3.2 A crystal structure of synaptotagmin III, residues 295-566, which includes the C2A and C2B domains, exhibits differences in the shape of the Ca(+2)-binding pocket, the electrostatic surface potential, and the stoichiometry of bound divalent cations for the two domains. These observations may explain the disparate binding properties of the two domains. The C2A and the C2B domains do not interact; synaptotagmin, therefore, covalently links two independent C2 domains, each with potentially different binding partners. A model of synaptotagmin's involvement in Ca(+2)-dependent regulation of membrane fusion through its interaction with the SNARE complex is presented.
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Affiliation(s)
- R. Bryan Sutton
- The Howard Hughes Medical Institute, Yale University, New Haven, Connecticut 06520
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
| | - James A. Ernst
- Department of Chemistry, Yale University, New Haven, Connecticut 06520
| | - Axel T. Brunger
- The Howard Hughes Medical Institute, Yale University, New Haven, Connecticut 06520
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
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Niles WD, Smith DO. Anion blockers inhibit impulse-evoked quantal transmitter release at the crayfish neuromuscular junction. J Physiol 1982; 329:203-10. [PMID: 6128409 PMCID: PMC1224775 DOI: 10.1113/jphysiol.1982.sp014298] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
1. The effects of the anion-transport blocking reagents Probenecid, 4,4'diisothiocyanostilbene-2,2'-disulphonate (DIDS), and pyridoxal phosphate on the number of quanta released (m) and the time course of the probability of quantal release, alpha(t), following an action potential were studied at single synaptic sites on the opener muscle in the crayfish leg.2. Low concentrations (10-50 muM) of DIDS or Probenecid produced decreases in m to about 30-50% of the initial value; at higher concentrations (100 muM or greater), evoked release failed. Much greater concentrations (500 muM) of pyridoxal phosphate were necessary to produce decreases in m.3. Synaptic depression in 50 muM-Probenecid was reversible by removing the agent; after treatment with 50 muM-DIDS, however, m partially regained the initial value upon removal of the drug.4. The time course of alpha(t) after an action potential was unaffected by any of the reagents.5. It is concluded that the reagents decrease the number of quanta evoked by a nerve impulse by decreasing the magnitude, but not the time course, of the average rate of quantal release following an action potential; it is suggested that nerves and other secretory cells may share a common mechanism during exocytosis that is subject to modification by these agents.
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