Harris Cholesterol Binding and Cholesterol Transport Proteins:

Structure and Function in Health and Disease
1. Auflage 2010
ISBN: 978-90-481-8622-8
Verlag: Springer Netherlands
Format: PDF
Kopierschutz: 1 - PDF Watermark

E-Book, Englisch, Band 51, 632 Seiten

Reihe: Subcellular Biochemistry

Knowledge of cholesterol and its interaction with protein molecules is of fundamental importance in both animal and human biology. This book contains 22 chapters, dealing in depth with structural and functional aspects of the currently known and extremely diverse unrelated families of cholesterol-binding and cholesterol transport proteins. By drawing together this range of topics the Editor has attempted to correlate this broad field of study for the first time. Technical aspects are given considerable emphasis, particularly in relation cholesterol reporter molecules and to the isolation and study of membrane cholesterol- and sphingomyelin-rich "raft" domains. Cell biological, biochemical and clinical topics are included in this book, which serve to emphasize the acknowledged and important benefits to be gained from the study of cholesterol and cholesterol-binding proteins within the biomedical sciences and the involvement of cholesterol in several clinical disorders.

It is hoped that by presenting this topic in this integrated manner that an appreciation of the fact that there is much more that needs to be taken into account, studied and understood than the widely discussed "bad and good cholesterol" associated, respectively, with the low- and high-density lipoproteins, LDL and HDL.

Autoren/Hrsg.

Harris, J. Robin

Inhaltsverzeichnis

1;Frontispiece;8
2;Preface;10
3;Contents;14
4;Contributors;18
5;1 CholesterolProtein Interaction: Methods and Cholesterol Reporter Molecules;23
5.1;1.1 Introduction;24
5.2;1.2 Cholesterol-Rich Microdomains;27
5.2.1;1.2.1 Detergent-Based Methods;28
5.2.2;1.2.2 Detergent-Free Methods;29
5.2.3;1.2.3 Receptors in Cholesterol-Rich Microdomains (Lipid Rafts);30
5.3;1.3 Manipulation of the Membrane Cholesterol Content by Cyclodextrins;31
5.4;1.4 Cholesterol-Binding Molecules;35
5.4.1;1.4.1 Polyenes;35
5.4.2;1.4.2 Cholesterol-Dependent Cytolysins;37
5.4.3;1.4.3 Enzymes with Cholesterol as Substrate;38
5.4.4;1.4.4 Other Cholesterol-binding Proteins;40
5.5;1.5 Binding Studies with Radiolabelled Cholesterol;42
5.6;1.6 Fluorescent Cholesterol Analogues;43
5.6.1;1.6.1 Dehydroergosterol;44
5.6.2;1.6.2 Cholestatrienol;47
5.6.3;1.6.3 NBD-Cholesterol;48
5.6.4;1.6.4 Bodipy-Cholesterol;49
5.6.5;1.6.5 Fluorescent PEG-Cholesterol;50
5.6.6;1.6.6 Dansyl-Cholestanol;50
5.7;1.7 Spin-Labelled Cholesterol;51
5.8;1.8 Affinity Labelling with Photoreactive Cholesterol;51
5.9;1.9 Concluding Remarks;54
5.10;References;55
6;2 Cholesterol in Alzheimer's Disease and other Amyloidogenic Disorders;68
6.1;2.1 Introduction;68
6.2;2.2 Cholesterol Metabolism and Alzheimers Disease;69
6.3;2.3 Cholesterol Binding to Aß and Aß Fibrillogenesis;72
6.3.1;2.3.1 Cholesterol and Membrane-Associated Aß Pore Formation and Fibrillogenesis;73
6.3.2;2.3.2 Gangliosides and Aß Fibrillogenesis;74
6.3.3;2.3.3 Cholesterol and In Vitro Aß Fibrillogenesis: Structural Studies;74
6.4;2.4 Apolipoprotein E, Cholesterol and Alzheimers Disease;78
6.5;2.5 Cholesterol Oxidation and Alzheimers Disease;81
6.6;2.6 Atherosclerosis and Alzheimers Disease;83
6.7;2.7 Cholesterol and Tau Fibrillization in AD, the Tauopathies and Non-A Amyloidogenic Disorders;84
6.8;2.8 Conclusions;86
6.9;References;86
7;3 Cholesterol-Binding Viral Proteins in Virus Entry and Morphogenesis;97
7.1;3.1 Introduction;99
7.1.1;3.1.1 Virus Lipidomics;100
7.1.2;3.1.2 Cholesterol Binding Sites;101
7.1.3;3.1.3 Methods Demonstrating Protein--Cholesterol Binding;102
7.2;3.2 Human Immunodeficiency Virus Fusion Protein gp41;105
7.2.1;3.2.1 Mutational Studies on the Pre-TM CRAC Motif in Virus-Cell Systems;106
7.2.2;3.2.2 Studies on Full-Length gp160, gp41 and Polypeptide Constructs;108
7.2.3;3.2.3 Peptide Studies and Modelling;108
7.3;3.3 Infuenza Virus M2 Protein;110
7.3.1;3.3.1 Influenza Virus Entry and Egress;110
7.3.2;3.3.2 M2 Protein Structural and Functional Domains;110
7.3.3;3.3.3 Influenza Virus Membrane Rafts;112
7.3.4;3.3.4 Cholesterol in the Apical Transport and Maturation of M2 Protein;112
7.3.5;3.3.5 M2 Protein-Cholesterol Binding Experiments;113
7.3.6;3.3.6 Membrane Raft Binding Determinants and CRAC Motifs in the Post-TM;114
7.3.7;3.3.7 Morphogenesis and Budding;116
7.3.8;3.3.8 Incorporation of M2 into Virus Particles and the Process of Membrane Fission;117
7.4;3.4 Fusion Proteins of Alphavirus Species;118
7.5;3.5 Other Cholesterol-Binding Virus Proteins;119
7.6;3.6 Conclusions;119
7.7;References;120
8;4 Sterol--Protein Interactions in Cholesterol and BileAcid Synthesis;129
8.1;4.1 Introduction;130
8.2;4.2 Brief Overview of Cholesterol and Bile Acid Biosynthesis;131
8.3;4.3 The Binding of (Chole)sterols to Cytochrome P450 Enzymes: Highly Stringent and Less Stringent EnzymeSubstrate Interactions;133
8.4;4.4 Bile AcidProtein Interactions: The Molecular Mechanisms Underlying Bile Acid Synthesis Feedback Regulation and Beyond;135
8.5;4.5 The Liver X Receptor: Sterol or Non-sterol, This Is the Question;140
8.6;4.6 Interactions Between Sterols and Sterol-Sensing Proteins Dictate Their Fate Toward Retention in the Endoplasmic Reticulum;143
8.7;4.7 Interactions Between Sterols and Sterol-Sensing Proteins Dictate their Fate Toward Degradation;147
8.8;4.8 Summary;148
8.9;4.9 Conclusions;150
8.10;References;150
9;5 Cholesterol Oxidase: Structure and Function;156
9.1;5.1 Introduction;156
9.2;5.2 Forms of Cholesterol Oxidase;157
9.3;5.3 Applications of Cholesterol Oxidase;159
9.4;5.4 Redox Properties of Cholesterol Oxidase;161
9.5;5.5 Structure Characterization;162
9.5.1;5.5.1 Non-covalent Enzyme Structure;162
9.5.2;5.5.2 Covalent Enzyme Structure;164
9.6;5.6 Catalytic Mechanism;165
9.6.1;5.6.1 Non-covalent Enzyme Mechanism;165
9.6.2;5.6.2 Covalent Enzyme Mechanism;168
9.7;5.7 Oxygen Channel;169
9.8;References;172
10;6 Oxysterol-Binding Proteins;178
10.1;6.1 Introduction;179
10.2;6.2 Pathways of Intracellular Cholesterol Transport;179
10.3;6.3 Cholesterol Transfer by Soluble Binding Proteins;180
10.4;6.4 Oxysterol-Binding Protein (OSBP) and OSBP-Related Proteins (ORPs);181
10.5;6.5 Phylogenetic Distribution of OSBP/ORPs;181
10.6;6.6 Structural Organization of the OSBP/ORP Family;183
10.6.1;6.6.1 Ligand Binding Domain;183
10.6.2;6.6.2 Organelle-Specific Targeting Domains;184
10.7;6.7 Role of Mammalian OSBP/ORPs in Sterol Transport and Signalling;185
10.7.1;6.7.1 OSBP;186
10.7.2;6.7.2 ORP1;189
10.7.3;6.7.3 ORP2;189
10.7.4;6.7.4 ORP3, ORP6 and ORP7;190
10.7.5;6.7.5 ORP4;191
10.7.6;6.7.6 ORP5 and ORP8;191
10.7.7;6.7.7 ORP9;192
10.7.8;6.7.8 ORP10 and ORP11;193
10.8;6.8 Summary and Conclusions;193
10.9;References;194
11;7 High Density Lipoprotein StructureFunction and Role in Reverse Cholesterol Transport;202
11.1;7.1 Introduction;203
11.2;7.2 Structures of ApoA-I and ApoE in the Lipid-Free State;204
11.2.1;7.2.1 Primary and Secondary Structures;204
11.2.2;7.2.2 Tertiary Structure;206
11.2.3;7.2.3 Quaternary Structure;209
11.3;7.3 Interaction of ApoA-I and ApoE with Lipids;210
11.3.1;7.3.1 Molecular Mechanism of Lipid-Binding;210
11.3.2;7.3.2 Apolipoprotein Conformation in Discoidal and Spherical HDL Particles;212
11.3.3;7.3.3 Remodeling of HDL Particles;214
11.4;7.4 Lipid Solubilizing Properties of ApoA-1 andApoE;216
11.4.1;7.4.1 Historical Perspective;216
11.4.2;7.4.2 Mechanism of Solubilization Reaction;218
11.4.3;7.4.3 Influence of Apolipoprotein Structure;220
11.5;7.5 HDL and Reverse Cholesterol Transport (RCT);221
11.5.1;7.5.1 Overview of RCT Pathway -- HDL Species and Receptors Involved;221
11.5.2;7.5.2 ABCA1;223
11.5.3;7.5.3 SR-BI;226
11.5.4;7.5.4 ApoE-HDL;229
11.6;7.6 HDL and Inflammation;231
11.6.1;7.6.1 Serum Amyloid A;231
11.7;7.7 Summary and Conclusions;232
11.8;References;233
12;8 Lipoprotein Modification and Macrophage Uptake: Role of Pathologic Cholesterol Transport in Atherogenesis;247
12.1;8.1 Introduction;248
12.1.1;8.1.1 Physiologic Role of LDL in Cholesterol Transport;248
12.1.2;8.1.2 Atherosclerosis and the LDL Paradox. Modified LDL;249
12.2;8.2 Mechanisms of LDL Oxidation and Enzymatic Degradation;250
12.3;8.3 Box 8.1 Evidence that LDL undergoes oxidation in vivo;250
12.3.1;8.2.1 LDL Oxidation by Copper;251
12.3.2;8.2.2 LDL Oxidation by Heme;252
12.3.3;8.2.3 Enzymatic and Cell-Mediated Oxidation of LDL;253
12.3.3.1;8.2.3.1 12/15-Lipoxygenase;253
12.3.3.2;8.2.3.2 Myeloperoxidase;254
12.3.3.3;8.2.3.3 Endothelial and Inducible Nitric Oxide Synthases and NADPH Oxidases;255
12.3.4;8.2.4 Non-oxidative Enzymatic Modifications of LDL;256
12.4;8.3 Macrophage Uptake of Modified LDL;256
12.5;8.4 Box 8.2 Major pathways mediating uptake of modified LDL by macrophages;256
12.5.1;8.3.1 Pattern-Recognition Receptors;257
12.5.1.1;8.3.1.1 CD36, SR-A and Other Scavenger Receptors;257
12.5.1.2;8.3.1.2 TLR4 and Macropinocytosis;259
12.5.1.3;8.3.1.3 Immune and Complement Complexes;260
12.5.2;8.3.2 Constitutive Macropinocytosis;260
12.5.3;8.3.3 Phagocytosis and Patocytosis of Aggregated LDL;260
12.5.4;8.3.4 LDLR Family Receptor-Mediated Uptake;261
12.6;8.4 Future Directions;261
12.6.1;8.4.1 Zebrafish Model for Studying Early Events in Atherogenesis;261
12.7;8.5 Summary;262
12.8;References;262
13;9 Cholesterol Interaction with Proteins That Partition into Membrane Domains: An Overview;270
13.1;9.1 Lipid Mixtures That Spontaneously Segregate into Cholesterol-Rich Domains;270
13.1.1;9.1.1 Lipid Mixtures Exhibiting Liquid--Liquid Phase Immiscibility;271
13.1.2;9.1.2 The Liquid Ordered Phase;271
13.1.3;9.1.3 Comparison Between the Domains Formed in Simple Lipid Mixtures and Those of Biological Membranes;271
13.1.4;9.1.4 Detection of Rafts in Biological Membranes;273
13.1.5;9.1.5 Properties of Rafts in Biological Membranes;273
13.1.6;9.1.6 Transbilayer Coupling and Rafts;274
13.2;9.2 Perturbation of Phase Behaviour by Proteins;275
13.3;9.3 Proteins Favouring Colocalization with Cholesterol;275
13.3.1;9.3.1 Lipidated Proteins;276
13.3.2;9.3.2 CRAC Motif;277
13.3.3;9.3.3 Sterol-Sensing Domains;285
13.4;9.4 Summary and Future Perspectives;287
13.5;References;288
14;10 Caveolin, Sterol Carrier Protein-2, MembraneCholesterol-Rich Microdomains and Intracellular Cholesterol Trafficking;296
14.1;10.1 Introduction;297
14.2;10.2 What Are Cholesterol-Rich and -Poor Microdomains?;297
14.3;10.3 How Is Cholesterol Organized Within Plasma Membranes?;299
14.4;10.4 What Are the Dynamics of Cholesterol Efflux in Cholesterol-Rich Versus -Poor Microdomains?;300
14.5;10.5 Does Membrane Lipid Composition Affect Cholesterol Dynamics in Cholesterol-Rich and -Poor Microdomains?;301
14.6;10.6 How May Plasma Membrane Proteins Regulate Cholesterol Dynamics?;302
14.7;10.7 How May Intracellular Cholesterol-Binding Proteins Regulate Cholesterol Dynamics?;303
14.7.1;10.7.1 Sterol Carrier Protein-2 (SCP-2);304
14.7.2;10.7.2 Liver Fatty Acid-Binding Protein (L-FABP);304
14.7.3;10.7.3 Steroidogenic Acute Regulatory Related (START) Proteins;305
14.7.4;10.7.4 Oxysterol Related Proteins (ORP);305
14.7.5;10.7.5 Niemann Pick C (NPC) Proteins;305
14.7.6;10.7.6 Other Intracellular Proteins;306
14.8;10.8 Sterol Carrier Protein-2 Facilitates Intermembrane Cholesterol Transfer In Vitro;306
14.9;10.9 Do Cholesterol-Rich and -Poor Microdomains Exist in the Plasma Membranes of Living Cells: Real-Time Multiphoton Imaging of a Naturally Fluorescent Sterol (Dehydroergosterol, DHE)?;307
14.10;10.10 Can the Existence of Cholesterol-Rich and -Poor Microdomains in Plasma Membranes of Living Cells Be Confirmed by Other Real-Time Approaches Using Synthetic Fluorescent Sterols Suitable for Confocal Imaging?;308
14.10.1;10.10.1 Colocalization of DChol with the Lipid-Rich Microdomain Marker GM 1 ;309
14.10.2;10.10.2 DChol Colocalization and Fluorescence Resonance Energy Transfer (FRET) with DiD, a Liquid Ordered Phase Lipid-Rich Microdomain Marker;310
14.10.3;10.10.3 FRET Between DChol and DHE in Living Cells;312
14.10.4;10.10.4 Colocalization and Fluorescence Resonance Energy Transfer (FRET) Between DChol and BC;313
14.10.5;10.10.5 Weak Colocalization and Absence of Fluorescence Resonance Energy Transfer (FRET) Between DChol and N-Rh-DOPE;314
14.11;10.11 Real-Time Imaging of Sterol Carrier Protein-2 Mediated Cholesterol Dynamics Through Cholesterol-Rich and -Poor Microdomains in Plasma Membranes of Cultured Cells;314
14.12;10.12 Physiological Studies of Effects of SCP-2 Overexpression and Gene Ablation on Cholesterol Dynamics;317
14.12.1;10.12.1 Effects of SCP-2 Over-Expression and Antisense Treatment on Hepatic and Biliary Cholesterol;318
14.12.2;10.12.2 Effects of SCP-2/SCP-x Gene Ablation on Hepatic and Biliary Cholesterol;318
14.13;10.13 Potential Compensation by Other Cholesterol-binding Proteins;319
14.14;10.14 Conclusions and Future Perspectives;322
14.15;References;323
15;11 Cholesterol in NiemannPick Type C disease;336
15.1;11.1 Introduction;336
15.2;11.2 NPC Proteins and Intracellular Cholesterol Transport;337
15.3;11.3 Cholesterol Accumulation in Niemann-Pick Type C Disease;338
15.4;11.4 Suppression of Brain Cholesterol Synthesis in NPC Disease;340
15.5;11.5 Impairment of Cholesterol Transport in NPC Disease;341
15.6;11.6 Cholesterol Accumulation-Associated Autophagy in NPC Disease;342
15.7;11.7 Treatment Development for NPC Disease;344
15.8;11.8 Conclusions;345
15.9;References;345
16;12 Protein Mediators of Sterol Transport Across Intestinal Brush Border Membrane;353
16.1;12.1 Introduction;354
16.2;12.2 Intestinal Cholesterol Absorption and Ezetimibe;354
16.3;12.3 NPC1L1;356
16.3.1;12.3.1 Structure: Gene, mRNA, and Protein Domains;356
16.3.2;12.3.2 Function: Lessons Learned from Animal Models and Human Genetics;358
16.3.3;12.3.3 Function: Lessons Learned from Cell Model Systems;359
16.3.4;12.3.4 Regulation of Expression;361
16.3.5;12.3.5 Cholesterol and Ezetimibe Binding Studies;363
16.3.6;12.3.6 Potential Mechanisms for NPC1L1 to Mediate Sterol Uptake;364
16.3.7;12.3.7 Therapeutic Perspectives;365
16.4;12.4 ATP-Binding Cassette Transporters G5 and G8 (ABCG5/G8);366
16.4.1;12.4.1 Discovery of ABCG5/G8: The Power of Human Genetics;366
16.4.2;12.4.2 Structure: Gene, mRNA, and Protein Domains;366
16.4.3;12.4.3 Function: Lessons Learned from Animal Models;367
16.4.4;12.4.4 Function: Lessons Learned from Cell Model Systems;368
16.4.5;12.4.5 Regulation of Expression;369
16.4.6;12.4.6 Biochemical Studies on ABCG5/G8-dependent Sterol Transport;370
16.4.7;12.4.7 Therapeutic Perspectives for ABCG5/G8;370
16.5;12.5 Scavenger Receptor Class B Type l (SR-Bl);372
16.5.1;12.5.1 Discovery of SR-BI;372
16.5.2;12.5.2 Structure: Gene, mRNA, and Protein Domains;372
16.5.3;12.5.3 Function: Lessons Learned from Animal Models;373
16.5.4;12.5.4 Function: Lessons Learned from Cell Model Systems;374
16.5.5;12.5.5 Regulation of Expression;375
16.5.6;12.5.6 Cholesterol Binding Studies;377
16.5.7;12.5.7 Therapeutic Perspectives for SR-BI;377
16.6;12.6 Other Proteins Influencing Intestinal Cholesterol Absorption;378
16.7;12.7 Concluding Comments;379
16.8;References;379
17;13 Cholesterol at the Endoplasmic Reticulum: Roles of the Sigma-1 Receptor Chaperone and Implications thereof in Human Diseases;397
17.1;13.1 Introduction;398
17.2;13.2 Structure and Subcellular Localization of the Sigma-1 Receptor;399
17.3;13.3 The Potential Link Between the Sigma-1 Receptor and Sterols;402
17.4;13.4 Sigma-1 Receptors Interact with Cholesterol;403
17.5;13.5 Molecular Function of the Sigma-1 Receptor;405
17.6;13.6 Ligand-Binding Profile of the Sigma-1 Receptor;406
17.7;13.7 Roles of Sigma-1 Receptors in Subcellular Distribution of Lipids and Reconstitution of Lipid Rafts;407
17.8;13.8 The Sigma-1 Receptor in Human Diseases;408
17.8.1;13.8.1 Neuropsychiatric Disorders;408
17.8.2;13.8.2 Cancer;409
17.9;13.9 Conclusions;409
17.10;References;410
18;14 Prominin-1: A Distinct Cholesterol-Binding Membrane Protein and the Organisation of the Apical Plasma Membrane of Epithelial Cells;415
18.1;14.1 Introduction;415
18.2;14.2 Prominin Molecules and Plasma Membrane Protrusions;417
18.2.1;14.2.1 Prominin -- Basic Facts;417
18.2.2;14.2.2 Prominin-1 and Photoreceptors;419
18.3;14.3 The Apical Plasma Membrane Contains Distinct Cholesterol-Based Membrane Microdomains;420
18.3.1;14.3.1 Prominin-1 -- A Cholesterol-Interacting Protein Associated with a Distinct Membrane Microdomain Subtype;420
18.3.2;14.3.2 Distinct Cholesterol-Based Membrane Microdomain Subtypes as Building Units of the Apical Plasma Membrane;423
18.3.3;14.3.3 Distinct Ganglioside-Associated Membrane Microdomain Within the Apical Plasma Membrane;425
18.3.4;14.3.4 How Are Prominins Incorporated into the Protrusion-Specific Subtype of Membrane Microdomains? -- Facts and Hypotheses;426
18.4;14.4 Dynamics of Apical Plasma Membrane Protrusions;427
18.4.1;14.4.1 Prominin-Containing Extracellular Membrane Vesicles;427
18.4.2;14.4.2 Role of Membrane Microdomains in the Release of Small Extracellular Membrane Vesicles;428
18.5;14.5 Perspectives;431
18.6;References;432
19;15 Mammalian StAR-Related Lipid Transfer (START) Domains with Specificity for Cholesterol: Structural Conservation and Mechanism of Reversible Binding;440
19.1;15.1 Introduction;440
19.2;15.2 The START Domains That Specifically Bind Cholesterol Have a Highly Conserved / Helix Grip Fold;443
19.3;15.3 To Be or Not to Be a Molten Globule to Bind and Release Cholesterol Reversibly?;444
19.4;15.4 Experimental Validation of the Two-State Model;445
19.5;15.5 Towards a Consensual Model for the Reversible and Specific Binding of Cholesterol by START Domain;449
19.6;15.6 Conclusions and Perspectives;450
19.7;References;450
20;16 Membrane Cholesterol in the Function and Organization of G-Protein Coupled Receptors;453
20.1;16.1 Introduction;454
20.2;16.2 Cholesterol in Biological Membranes: A Tale of Two Faces;455
20.3;16.3 Role of Membrane Cholesterol in the Function of G-Protein Coupled Receptors;457
20.3.1;16.3.1 Effect of Membrane Cholesterol on the Function of GPCRs: General Effect or Specific Interaction ?;458
20.3.1.1;16.3.1.1 Rhodopsin;459
20.3.1.2;16.3.1.2 Oxytocin and Cholecystokinin Receptors;460
20.3.1.3;16.3.1.3 Galanin Receptors;461
20.4;16.4 Nonannular Lipids in the Function of Membrane Proteins;461
20.4.1;16.4.1 Presence of Specific (Nonannular?) Cholesterol binding Sites in the Crystal Structures of GPCRs;463
20.4.1.1;16.4.1.1 Rhodopsin;463
20.4.1.2;16.4.1.2 0 ß2-Adrenergic Receptor;463
20.5;16.5 The Serotonin 1A Receptor: A Representative Member of the GPCR Superfamily in the Context of Membrane Cholesterol Dependence for Receptor Function;466
20.5.1;16.5.1 Cholesterol binding Motif(s) in Serotonin 1A Receptors?;471
20.6;16.6 Conclusion and Future Perspectives;471
20.7;References;473
21;17 Cholesterol Effects on Nicotinic Acetylcholine Receptor: Cellular Aspects;481
21.1;17.1 Introduction;482
21.2;17.2 The Natural Scenario of AChR-Cholesterol Interactions;483
21.3;17.3 Lipid-AChR Interactions at the Cellular Scale. Tentative Association of AChR Clusters with a Specific Subset of Lipid Domains, the Lipid Rafts;484
21.4;17.4 Cholesterol Sensitivity of AChR Exocytic Trafficking;486
21.5;17.5 Cholesterol Sensitivity of AChR Endocytosis;486
21.6;17.6 Diffuse AChRs Are in Fact Organized in the Form of Nanoclusters at the Cell Surface;491
21.7;17.7 How Do Cholesterol Levels Modulate AChR Stability at the Cell Membrane?;493
21.8;17.8 Possible Relationship Between AChR Nanocluster Organization and the Membrane-Associated Cortical Cytoskeletal Network;494
21.9;17.9 A Word on Cholesterol Binding Sites;496
21.10;References;497
22;18 Cholesterol and Myelin Biogenesis;502
22.1;18.1 Introduction;502
22.2;18.2 Myelin Structure and Composition;503
22.3;18.3 Schwann Cells;504
22.3.1;18.3.1 The Origin and Differentiation of Schwann Cells;505
22.3.2;18.3.2 Origin and Differentiation of Oligodendrocytes;507
22.4;18.4 Source of Cholesterol in Myelin;508
22.5;18.5 Cholesterol-Binding Proteins in Myelin;510
22.6;18.6 Cholesterol Depletion in Oligodendrocytes and Schwann cells In Vivo;512
22.7;18.7 Conclusions;516
22.8;References;517
23;19 Cholesterol and Ion Channels;522
23.1;19.1 Introduction;522
23.2;19.2 Cholesterol Regulation of K+ Channels;525
23.2.1;19.2.1 Inwardly Rectifying K+ (Kir) Channels;525
23.2.2;19.2.2 Kir2 Channels;526
23.2.3;19.2.3 Kir3 Channels;528
23.2.4;19.2.4 Kir4 Channels;529
23.2.5;19.2.5 Kir6 (K ATP) Channels;529
23.3;19.3 Association of Kir Channels with Cholesterol-Rich Membrane Domains (Lipid Rafts);529
23.3.1;19.3.1 Regulation of Kir Channels by Plasma Hypercholesterolemia In Vivo ;530
23.4;19.4 Voltage-Gated K+ (Kv) Channels;531
23.4.1;19.4.1 Kv1 Channels;532
23.4.2;19.4.2 Kv2 Channels;533
23.4.3;19.4.3 Other Kv Channels;533
23.4.4;19.4.4 Regulation of Kv Channels by Plasma Hypercholesterolemia;534
23.5;19.5 Ca2+ -Activated K+ Channels;534
23.5.1;19.5.1 BK;536
23.5.2;19.5.2 SK and IK;537
23.6;19.6 Na+ Channels;538
23.6.1;19.6.1 Voltage-Gated Na+ (Nav) Channels;538
23.6.2;19.6.2 Epithelial Na+ Channels (eNaC);540
23.7;19.7 Ca+ Channels;540
23.7.1;19.7.1 Voltage-Gated Ca+ 2 (Cav) Channels;541
23.7.2;19.7.2 L-Type Ca2+ Channels;541
23.7.3;19.7.3 N-Type Ca2+ Channels;542
23.8;19.8 Transient Receptor Potential (TRP) Channels;542
23.8.1;19.8.1 TRPV Channels;543
23.8.2;19.8.2 TRPC Channels;543
23.9;19.9 TRPM Channels;545
23.10;19.10 Cl- Channels;545
23.10.1;19.10.1 Voltage-Gated Cl- Channels;546
23.10.2;19.10.2 CFTR;547
23.11;19.11 Volume-Regulated Anion Channel (VRAC);547
23.12;19.12 Mechanosensitive Channels;548
23.13;19.13 Concluding Remarks and Future Directions;550
23.14;References;551
24;20 The Cholesterol-Dependent Cytolysin Family of Gram-Positive Bacterial Toxins;563
24.1;20.1 Introduction;564
24.2;20.2 Mechanism of Pore Formation;564
24.2.1;20.2.1 Localizing the Target Membrane;569
24.2.2;20.2.2 Grouping Forces on the Membrane Surface: Pre-pore Formation;569
24.2.3;20.2.3 Perforating the Membrane: Insertion of a Large ß-Barrel;572
24.3;20.3 The Role of Cholesterol in Membrane Binding;573
24.3.1;20.3.1 Domain 4 and Membrane Recognition;573
24.3.1.1;20.3.1.1 The Conserved Loops;574
24.3.2;20.3.2 Searching for Cholesterol in the Membrane;576
24.3.2.1;20.3.2.1 Cholesterol Availability in Membrane Bilayers;577
24.3.2.2;20.3.2.2 The Role of Other Lipids;578
24.3.2.3;20.3.2.3 Cholesterol Alone Is Enough;580
24.4;20.4 Conclusions and Future Perspectives;581
24.5;References;583
25;21 Cholesterol Specificity of Some Heptameric -Barrel Pore-Forming Bacterial Toxins: Structural and Functional Aspects;590
25.1;21.1 Introduction;590
25.2;21.2 Vibrio cholerae Cytolysin (VCC);591
25.2.1;21.2.1 Structure of the VCC Oligomer;592
25.2.2;21.2.2 Fibril Formation by VCC and Other Toxins In Vitro;598
25.3;21.3 Hemolysins/Cytolysins from Other Vibrio Species;599
25.4;21.4 Cholesterol Dependency of Heptameric and Other -Barrel-Forming Hemolysins/Toxins from Non- Vibrio Species;600
25.5;21.5 Conclusions;602
25.6;References;603
26;22 Cholesterol-Binding Toxins and Anti-cholesterol Antibodies as Structural Probes for Cholesterol Localization;608
26.1;22.1 Introduction;609
26.2;22.2 Cholesterol-Binding Toxins;609
26.2.1;22.2.1 Preparation of Non-cytolytic Derivatives of Perfringolysin O;610
26.2.2;22.2.2 Binding Properties of Perfringolysin O Derivatives;612
26.2.2.1;22.2.2.1 Specific Binding to Cholesterol;612
26.2.2.2;22.2.2.2 Selective Binding to Cholesterol-Enriched Membranes;614
26.2.3;22.2.3 Application of Perfringolysin O Derivatives to the Detection of Cholesterol-Rich Membranes;617
26.2.3.1;22.2.3.1 BC as a Marker of Cholesterol-Rich Microdomains on the Cell Surface;618
26.2.3.2;22.2.3.2 Detection of Cholesterol-Rich Microdomains in the Inner Leaflet of the Plasma Membrane;619
26.2.3.3;22.2.3.3 Electron Microscopic Analysis of Microdomains in Intracellular Membranes;620
26.2.3.4;22.2.3.4 Microdomains in T-cell Receptor Signalling;621
26.2.3.5;22.2.3.5 Microdomains in Cholesterol Storage/Transport Disorders;622
26.3;22.3 Anti-cholesterol Antibodies;624
26.3.1;22.3.1 Characterization and Binding Properties;624
26.3.2;22.3.2 Application to Cellular Cholesterol Detection;625
26.4;22.4 Conclusions;626
26.5;References;626
27;Index;633