Transporters and Pumps in Plant Signaling (eBook)

Transporters and Pumps in Plant Signaling 3
Preface 5
Contents 7
Part I: Membranes and Water Transport 9
Plant Aquaporins: Roles in Water Homeostasis, Nutrition, and Signaling Processes 10
1 Introduction 10
2 Plant Aquaporins 12
2.1 Plasma Membrane Intrinsic Proteins 12
2.2 Tonoplast Intrinsic Proteins 13
2.3 Small Basic Intrinsic Proteins 14
2.4 Nodulin26-Like Intrinsic Proteins 16
2.5 X Intrinsic Proteins 17
2.6 Hybrid Intrinsic Proteins 17
2.7 GlpF-Like Intrinsic Proteins 17
3 Structural Features of Major Intrinsic Proteins 18
3.1 Aquaporin Structure 18
3.2 Aromatic/Arginine (ar/R) Constriction Region 19
3.3 Oligomer Formation 19
4 Why Do Plants Contain So Many MIP Isoforms? 21
4.1 MIP Function Related to Water Transport 22
4.2 MIP Function Related to Nitric Oxide Transport 23
4.3 MIP Function Related to Ammonia Transport 24
4.4 MIP Function Related to Urea Transport 25
4.5 MIP Function Related to Carbon Dioxide Transport 26
4.6 MIP Function Related to Hydrogen Peroxide Transport 27
4.7 MIP Function Related to Organic Acid Transport 28
4.8 MIP Function Related to Glycerol Transport 29
4.9 MIP Function Related to Boric Acid Transport 30
4.10 MIP Function Related to Silicic Acid Transport 31
4.11 MIP Function Related to Arsenite/Antimonite Transport 31
5 Conclusion 33
References 33
Part II: Signaling Related to Ion Transport 44
Plant Proton Pumps: Regulatory Circuits Involving H+-ATPase and H+-PPase 45
1 P-Type H+-ATPases 45
1.1 Arabidopsis Encodes 11 Members of H+-ATPases 46
1.2 Mechanism of Activation by 14-3-3 Proteins 47
1.3 Phosphoproteomic Studies of Plasma Membrane H+-ATPases 48
1.4 Controlling the Size of the Stomatal Pore 49
1.4.1 Opening of Guard Cells 49
1.4.2 Closure of Guard Cells 50
1.4.3 Pathogens Modulate the H+ Pumps to Invade Plants Through the Stomatal Pore 50
1.5 PKS5: A Protein Kinase Preventing Binding of 14-3-3 Protein 51
1.5.1 ScaBP1: A Calcium Binding Protein Modulating PKS5 Action 51
1.5.2 DnaJ: A Chaperone Like Protein Repressing PKS5 Activity 52
1.6 Nutrient Uptake and Responses to Changes in the Soil 52
1.6.1 Response to Limited Phosphate 53
2 Plant H+-PPases 53
2.1 Vacuolar H+-PPases in Fruits 55
2.2 Vacuolar H+-PPase Is a Key Player for Plant Salt Tolerance 56
2.3 Vacuolar H+-PPases in Maize Aleurone 56
2.4 Subcellular Localization of Plant H+-PPases 57
2.5 Are There Other H+-PPases in Plants? 58
2.6 Transcriptional Regulation of H+-PPases 58
2.6.1 Sugar Starvation 59
2.6.2 Pi Starvation 60
2.7 Puzzling Phenotypes Triggered by Altering the Expression of H+-PPases in Plants 60
2.8 Could the H+-PPase Affect Sucrose Phloem Loading? 61
2.8.1 PPi Concentrations Are Essential for Sucrose Phloem Loading 61
2.8.2 H+-PPase and H+-ATPase Localize in Close Proximity at the PM of Sieve Elements 61
2.8.3 Hypothetical Model 62
References 63
Na+ and K+ Transporters in Plant Signaling 71
1 Introduction 72
2 K+ Transport 72
2.1 K+ Uptake from Diluted Solutions and Plant Signaling 73
2.2 Transcriptional Regulation of High-Affinity HAK Transporters 74
2.3 Regulation of AKT1 Channels by Phosphorylation/Dephosphorylation 78
3 Sodium Transport 80
3.1 Sodium Influx at the Plasma Membrane 80
3.2 Sodium Efflux and Long-Distance Transport the SOS System85
3.3 Transport at the Tonoplast for Na+ Sequestration 91
4 Concluding Remarks 94
References 95
Iron Transport and Signaling in Plants 105
1 Introduction 105
2 Fe Transport and Signaling in Yeast and Mammalian Cells 106
2.1 A Brief Overview of Fe Transport and Signaling in Yeast 106
2.2 A Brief Overview of Fe Transport and Signaling in Mammals 107
3 Fe Transport Systems in Plant Cells 108
3.1 Fe Uptake 108
3.1.1 Strategy I 108
3.1.2 Strategy II 110
3.2 Intracellular Fe Distribution 111
3.2.1 Vacuole 112
3.2.2 Chloroplast 113
3.2.3 Mitochondria 114
3.2.4 Other Compartments 114
3.3 Long-Distance Transport 115
3.3.1 Xylem Transport 115
3.3.2 Phloem Transport 115
4 Mechanisms of the Regulation of Fe Uptake in Plants 116
4.1 Transcriptional Control of Fe Uptake in Strategy I Plants 116
4.2 Post-transcriptional Control of Fe Acquisition Mechanisms in Strategy I Plants 118
4.3 Transcriptional Control of Fe Uptake in Strategy II Plants 119
5 Local Versus Long-Distance Regulation 121
6 Hormonal Signals 123
6.1 Ethylene 124
6.2 Cytokinins 125
6.3 Nitric Oxide 125
7 Diurnal Regulation and Control by the Circadian Clock 127
8 Conclusion 128
References 129
Ca2+ Pumps and Ca2+ Antiporters in Plant Development 138
1 Introduction 138
2 Ca2+-ATPases 141
2.1 Characteristics of Type 2A Ca2+-ATPases (ECAs) 142
2.2 Characteristics of Type 2B Ca2+-ATPases (ACAs) 143
2.3 Physiological Role of Ca2+-ATPases 148
3 Ca2+/H+ Antiporters 151
3.1 Biochemical and Regulatory Properties of Ca2+/H+ Antiporters 152
3.2 Roles of Ca2+/H+ Antiporters in Ca2+ Signaling and Plant Development 155
4 Summary and Future Perspectives 158
References 159
Part III: Nutrient Transport 167
Nitrate Transporters and Root Architecture 168
1 Introduction 168
2 NO3- at the Whole Plant Level 170
3 Physiology of the Root and NO3- 172
3.1 Root Development 172
3.2 The Influence of NO3- on RSA 173
3.3 Root Water Influences NO3- Uptake 173
4 Achieving Uptake: NRTs 174
4.1 High- and Low-affinity Transport Systems 174
4.2 NRT1s 175
4.3 NRT2s 176
4.4 NAR2s (NRT3) 178
5 Molecular Regulation of Nitrate Transporters 178
5.1 Gene Expression 178
5.2 Post-translational Regulation of NRTs 179
5.3 Overlap with Hormones 180
6 NO3- Signaling 182
7 Conclusions 185
8 Outlook 186
References 188
Sensing and Signaling of PO43- 194
1 Introduction 195
1.1 Necessity and Low Availability 195
2 Mechanisms of Acquisition and Transport of Phosphate 196
2.1 Going Through Membranes 196
2.1.1 Phosphate Transporters H+/Pi Symporter 196
2.1.2 Pi Translocators 198
2.2 Pi Uptake and Translocation into the Plant 200
3 Adaptation of Plants to Pi Starvation 201
3.1 Increasing the Pi Availability 201
3.1.1 Phosphorus Is Solubilized 201
3.2 Enhancing Pi Uptake, 202
3.2.1 Phosphate Transport, and Translocation 202
3.2.2 Increasing in Root Absorption Area 204
3.3 Recovering Pi from the Cell Membrane 206
3.4 Metabolic Alterations 206
4 Regulation of the Low Pi Rescue System 207
4.1 Pi Sensing 207
4.1.1 Pi Local Sensing 207
4.1.2 Long Distance Sensing 209
4.1.3 SPX Genes Domain Role in Pi Sensing 209
4.2 Regulation of Transcription 210
4.2.1 Chromatin Structure Modifications 210
4.2.2 Transcription Factors 211
4.2.3 Hormonal Regulation 213
5 Pi Homeostasis 215
5.1 Phosphate Signaling Pathway Dependent on PHR1, PHO2 and MicroRNA399 215
5.2 Emerging Insights into Ca2+ Roles in Pi Homeostasis 216
5.3 Soil Minerals Affecting Pi Response 216
6 Conclusions 217
References 218
Sucrose Transporters and Plant Development 228
1 Plants Contain More than One Sucrose Transporter 228
2 Sucrose Transporters from Monocotyledonous Plants 230
3 Sucrose Efflux 231
4 Phloem Mobility of Sucrose Transporter mRNAs 231
5 Sucrose Import into the Sieve Element-Companion Cell Complex 232
6 Vacuolar Sucrose Transporters 235
7 Substrate Specificity of Sucrose Transporters 236
8 Sucrose Facilitators (SUFs) 237
9 Regulation of Sucrose Transporters 237
9.1 Regulation at the Transcriptional Level 237
9.2 Post-transcriptional Regulation of Sucrose Transporters 238
9.3 Translational Control of Sucrose Transporter Expression 239
9.4 Post-translational Control of Sucrose Transporter Expression 239
9.4.1 Phosphorylation/Dephosphorylation 239
9.4.2 Redox-dependent Targeting and Dimerization 240
9.4.3 Protein-Protein Interactions of Sucrose Transporters 240
9.4.4 Subcellular Localisation of Sucrose Transporters 240
10 Potential Function of Sucrose Transporters in Sink Organs 241
10.1 Members of the SUT2 Subfamily of Sucrose Transporters 241
10.2 Members of the SUT4 Subfamily of Sucrose Transporters 243
11 Phloem Mobile Signals 244
11.1 Phloem RNAs 244
11.2 MicroRNAs 244
11.3 Metabolites (Sucrose) 245
11.4 Ca2+, ROS, Electric Potential Waves 245
12 Sucrose Transport and Plant Signaling 246
13 Conclusion 248
References 248
Part IV: Signaling Molecules 255
Auxin Transporters Controlling Plant Development 256
1 Introduction: Auxin as the Signaling Molecule 256
1.1 Auxin: The ``Slavey´´ in Plant Growth and Development 256
1.2 Physical-Chemical Properties of Auxin Molecule: The (Molecular) Form Does Matter! 257
2 Auxin Transporters: Inward, Outward, and Within the Cell 258
2.1 Auxin Carriers: Source of Energy and Topology 258
2.2 Auxin Uptake/Influx Carriers 261
2.3 Auxin Efflux Carriers 262
2.4 Intracellular Auxin Carriers 264
3 Regulation of Auxin Transporters´ Function: How, How Much, and Where? 264
3.1 Levels of Regulation 264
3.2 The Abundance of Auxin Carriers: Transcription, Translation, and Degradation 266
3.3 Intracellular Trafficking and Targeting of Auxin Carriers 267
3.4 Regulation of the Auxin Carrier Proteins´ Activity 270
4 Auxin Transporters in Plant Development: When and Why? 272
4.1 The Formation of Auxin Gradients: Morphogenic Action of Auxin 272
4.2 Auxin Transporters During Embryogenesis 273
4.3 Auxin Transporters During Root and Shoot Development 275
4.4 Auxin Transporters During Tropisms 277
5 Quantitative Aspects of Auxin Flow: Not Just the Form but Also the Amount Matters 278
6 Evolutionary Aspects: Many Transporters and What Was the First? 279
7 Conclusions: There Is No Proper Development Without Auxin (Transporters) 280
References 281
Part V: Membrane Structures and Development, Trafficking and Lipid-Transporter Interactions 292
V-ATPases: Rotary Engines for Transport and Traffic 293
1 Introduction 293
2 The V-ATPase Structure and Mechanism of a Complex Proton Pump 294
2.1 Subunit Composition 294
3 Levels of V-ATPase Regulation 297
3.1 V-ATPase Isoforms: The Even More Complex Pump of Higher Plants 297
3.2 Assembly of the V-ATPase: Putting the Pieces Together 300
3.3 Reversible Dissociation: Pulling the Complex Apart 301
3.4 Redox Regulation: An On- and Off-Switch? 302
3.5 Fine-Tuning by Protein Phosphorylation? 302
4 Genetic Studies: The Plant V-ATPase Is Essential: But Where? 303
4.1 The V-ATPase in the TGN/EE: Essential for Endocytic and Secretory Traffic 304
4.2 The Vacuolar V-ATPase: Important but Not Essential 305
4.3 The V-ATPase and Its Role in Salt Tolerance 306
5 Conclusion 307
References 307
Type IV (P4) and V (P5) P-ATPases in Lipid Translocation and Membrane Trafficking 313
1 Introduction 313
2 P4-ATPases 314
2.1 General Features 314
2.2 P4-ATPases in Plants and Their Subcellular Localisation 314
2.3 Tissue-specific Expression of Arabidopsis P4-ATPases 315
2.4 The Cdc50p Homologue Family As beta-subunits for P4-ATPases 316
2.4.1 General Features 316
2.4.2 Putative Role of P4-ATPase beta-subunits 316
2.5 Role of Plant P4-ATPases in Phospholipid Translocation 318
2.6 Role of Plant P4-ATPases in Membrane Trafficking 319
3 P5-ATPases 319
3.1 General Features 319
3.2 Physiological Role of P5A-ATPases 320
3.3 What Is the Substrate of P5A-ATPases? 321
4 Conclusions 322
References 322
Peroxisomal Transport Systems: Roles in Signaling and Metabolism 327
1 Introduction 327
2 The Peroxisomal Membrane as a Boundary: Permeability and Porins vs. Selective Transporters 330
2.1 Evidence for Peroxisomal Porins 330
2.2 Evidence for Specific Transporters 331
3 Import of Substrates, Cofactors and Co-Substrates for beta-Oxidation 331
3.1 ABC Transporters 333
3.2 Adenine Nucleotide Translocator 338
3.3 The Peroxisomal CoA Budget 338
3.4 Phosphate Transport 339
3.5 Import of Other Cofactors 339
4 Glyoxylate Cycle and Fatty Acid Respiration 340
4.1 Metabolite and Redox Shuttles Transport Requirements of the Glyoxylate Cycle340
5 Photorespiration 341
6 Peroxisomal pH 341
7 Peroxisomes as a Source of Signaling Molecules 343
8 Conclusions 344
References 344
Regulation of Plant Transporters by Lipids and Microdomains 352
1 General Principles of the Regulation of Transporters and Channels Through Lipid Annulus, Cofactors and Membrane Raft Microdomains 352
1.1 Lipids as Solvent: Annular Lipids 354
1.1.1 Importance of the Polar Head 354
1.1.2 Importance of the Hydrophobic Thickness 355
1.1.3 Effect of Membrane Viscosity 356
1.1.4 Effect of Interfacial Curvature and Elastic Strain 357
1.1.5 Effect of Membrane Tension: Mechanosensitive Ion Channels and Osmoregulated Transporters 357
1.1.6 Role of Asymetrical Distribution of Lipids Across the Plasma Membrane in the Permeability to Solutes 358
1.2 Lipids as Cofactors: Nonannular Lipids 358
1.3 Compartmentalization of Membrane Proteins Within Particular Domains of the Membrane 360
1.3.1 Definition of Membrane Rafts 360
1.3.2 Characterization of Plant Membrane Rafts 361
2 Regulation of Plant Transporters by Lipids 362
2.1 Examples of Regulation by Association to Microdomains 362
2.1.1 Channels 362
2.1.2 Pumps 363
2.1.3 Transporters 364
ABC Transporters 364
Amino-Acid Transporters 366
Sucrose Transporters 366
2.2 Examples of Regulation by Lipids as Cofactors 367
2.2.1 Channels 367
2.2.2 Pumps 369
2.2.3 Transporters 370
3 Conclusion 370
References 371
Index 377