Integrated G Proteins Signaling in Plants (eBook)

Shaul Yalovsky, František Baluška, Alan Jones (Herausgeber)

eBook Download: PDF

2009 | 2010
X, 336 Seiten
Springer Berlin (Verlag)
978-3-642-03524-1 (ISBN)

Infos

This volume focuses on the structure, function and regulation of plant signaling G proteins and their function in hormonal pathways, polarity, differentiation, morphogenesis and responses to biotic and abiotic stresses.

Plants are sessile organisms that need to continuously coordinate between external and internal cues. This coordination requires the existence of hubs to allow cross-talk between different signaling pathways. A single family of Rho GTPases, termed either ROPS or RACs, and heterotrimeric G proteins have emerged as the major molecular switches in a multitude of signal transduction pathway in plants.

Inhalt

Preface 4
Contents 8
Plant Ga Structure and Properties 10
1 Introduction: Structure–function Relationships in G Protein Signaling 11
2 Comparison of Plant Ga Proteins to Mammalian Ga Proteins 12
2.1 Switch Regions and the Gbg Interacting Interface 12
2.2 Guanine Nucleotide-Binding Pocket 16
2.3 Loop Insertions 17
2.4 The a5 Helix 17
2.5 RGS Interacting Interface 18
2.6 Receptor and Effector Coupling 18
2.7 Cholera Toxin and Pertussis Toxin 19
2.8 Contacts Between Ras-like and Helical Domains ( Linkers 1 and 2) 19
2.9 Other Residues of Interest: Tools for Studying G Protein Signaling 19
2.10 Summary of Structural Comparison Between Plant and Mammalian Ga Proteins 20
3 Properties of Plant Ga Proteins 20
3.1 Kinetic Properties of the Arabidopsis Ga Protein 20
3.2 Kinetic Properties of Other Plant Ga Proteins 21
3.3 Possible Structural Determinants of Rapid Nucleotide Exchange 22
3.4 Plant Ga Lipid Modification and Subcellular Localization 22
3.5 Candidate Plant GPCRs 23
3.6 Candidate Plant Ga Effectors 25
3.7 Candidate Effectors in Plants Identified by Homology to Animal Effectors 27
4 Conclusions: Plant Ga Proteins are like Animal Ga Proteins, but Different 28
References 29
Regulatory and Cellular Functions of Plant RhoGAPs and RhoGDIs 35
1 Introduction 35
2 RhoGAP Protein Families 37
2.1 Plant RhoGAP SubFamily I: CRIB domain proteins 40
2.2 Plant RhoGAP Subfamily II: PH Domain Proteins 45
3 RhoGDI Protein Families 47
3.1 AtROPGDI1: Maintenance of Cellular Polarity Required for Root Hair Initiation and Growth 49
3.2 NtRhoGDI2: Maintenance of Polarized Rho GTPase Activation at the Tip of Tobacco Pollen Tubes 50
4 Conclusions 52
References 53
Structure and Function of ROPs and their GEFs 57
1 Introduction 57
2 Structure and Function of ROPs 59
2.1 Structural Characteristics of ROP Proteins 59
2.2 Nucleotide Binding, GTPase Activity, and Commonly Used Mutants 62

2.3 Plant- and Isoform-Specific Structural Features 63
3 RopGEFs: Novel Activators for Rho Proteins in Plants 65
3.1 Identification of RopGEFs 65
3.2 Architecture of RopGEFs and Mode of Substrate Binding 66
3.3 Insights into the Catalytic Mechanism of RopGEFs 67
3.4 Substrate Specificity of RopGEFs 71
3.5 RopGEFs in the Physiological Context 72
4 Conclusions 73
References 73
Protein–Lipid Modifications and Targeting of ROP/ RAC and Heterotrimeric G Proteins 78
1 Introduction 78
2 The Lipid Modifications 2.1 Prenylation and CaaX Processing 80
2.2 S-Acylation 82
2.3 N-Myristoylation 84
3 Lipid Modifications and Subcellular Targeting of ROPs 3.1 Subcellular Distribution and Function of ROPs 84

3.2 Prenylation of Type-I ROPs 85
3.3 Transient S-Acylation of Type-I ROPs 86
3.4 Stable S-Acylation of Type-II ROPs 87
3.5 Role of the Polybasic Domain for Plasma Membrane Targeting 88
4 Plasma Membrane Microdomains 4.1 The Lipid Raft Hypothesis 90
4.2 Accumulation of ROPs in Membrane Microdomains 90
5 Lipid Modifications and RhoGDI 91
6 Lipid Modifications and Targeting of Heterotrimeric G Proteins 6.1 Modification of the Ga and Function of Hetertrimeric G Protein in Plants 91
6.2 Prenylation and S-Acylation of Gg Subunits 92
7 Conclusions 93
References 93
ROP GTPases and the Cytoskeleton 98
1 Introduction 98
2 Regulation of AFs 99
2.1 Conserved Rho GTPase Downstream Pathways in the Regulation of AFs 100
2.2 Plant-Specific Players in the ROP-Dependent Regulation of AFs 102
3 Regulation of Microtubules 104
4 Crosstalk Between AFs, MTs, and ROPs 105
5 Conclusion and Perspectives 106
References 107
RAC/ROP GTPases in the Regulation of Polarity and Polar Cell Growth* 112
1 Introduction 113
2 RAC/ROP, a Tip-Localized Regulator for the Polarized Pollen Tube Growth Process 114
3 RAC/ROPs as Regulators for Root Hair Tip Growth 118
4 RAC/ROPs as Regulators of Polarized Cellular Activity Associated with Differentiation, Development and Defense 121
5 Insights from Upstream RAC/ROP Regulators on Their Role in Polarized Cell Growth 123
6 Perspective 124
References 125
Heterotrimeric G Proteins and Plant Hormone Signaling in Rice 130
1 Introduction 130
2 Analysis of the Rice d1 Mutant Deficient in the Heterotrimeric G Protein a Subunit ( Ga) Gene 131
3 Response of the Rice d1 Mutants to Plant Hormones 133
4 Interdependency of Plant Heterotrimeric G Protein Signaling and Plant Hormone Signaling 137
References 138
Auxin, Brassinosteroids, and G-Protein Signaling 142
1 Auxin Signaling 1.1 Auxin Physiological Functions in Higher Plants 142
1.2 Auxin Biosynthesis Pathway 143
1.3 Polar Auxin Transport 144
1.4 Auxin Signal Transduction in Higher Plants 145
2 Brassinosteroids 2.1 Physiological Functions of Brassinosteroids in Higher Plants 147
2.2 Brassinosteroid Synthesis Pathway 147
2.3 Brassinosteroid Signal Transduction 148
3 Physiological Functions of G-Protein Signaling in Arabidopsis and Rice 150
4 Cross talk Between Signaling of Auxin, Brassinosteroids, and G Protein 4.1 Cross talk Between Auxin Signaling and Heterotrimeric G Protein 152
4.2 Cross talk Between Brassinosteroids Signaling Transduction and Heterotrimeric G Protein 153
5 Future Prospects 154
References 155
Heterotrimeric G-Proteins and Cell Division in Plants 162
1 Introduction 162
2 Heterotrimeric G-Proteins and Component Proteins in Plants 163
3 Gene Expression and Protein Localization Studies Support a Role of G- Proteins in Cell Division 3.1 Ga Expression and Localization 164
3.2 Gb Expression and Localization 168
3.3 Gene Expression and Location Studies of Gg Subunits and Component Proteins 169
4 Pharmacological Analysis Supports a Role of G-Proteins in Cell Division 169
5 Genetic Characterization Provides Direct Evidence that G- Proteins Play a Modulatory Role in Cell Division 170
5.1 Heterotrimeric G-Proteins and Hypocotyl Cell Division 171
5.2 Heterotrimeric G-Proteins and Leaf Cell Division 173
5.3 Heterotrimeric G-Proteins and Root Cell Division 174
6 G-Protein Subunits May Target Different Nuclear Stage in Regulating Cell Division 177
7 Concluding Remarks 177
References 179
Heterotrimeric G Protein Regulation of Stomatal Movements 184
1 Introduction 184
2 Mechanisms of Stomatal Movements 187
2.1 Light-Induced Stomatal Opening 188
2.2 ABA Promotion of Closure 188
3 Measuring Stomatal Movements and Ion Channel Activities 3.1 Electrophysiological Studies of Guard Cells 189
3.2 Stomatal Aperture Assays 189
3.3 Whole-Leaf/Plant Measures of Stomatal Function 189
4 G-protein Regulation of Stomatal Movements 190
4.1 Early Pharmacological Studies 190
4.2 Arabidopsis Heterotrimeric G-Protein Genes 191
4.3 G protein Regulation of ABA Inhibition of Light-Induced Stomatal Opening 193
4.4 G Protein Regulation of ABA Promotion of Stomatal Closure 195
4.5 G Protein Regulation of Pathogen-Induced Stomatal Movements 196
4.6 G Protein Regulation of Whole-Leaf Water Status and Drought Response 196
5 Conclusions and Unanswered Questions 197
References 198
The Role of Seven-Transmembrane Domain MLO Proteins, Heterotrimeric G- Proteins, and Monomeric RAC/ ROPs in Plant Defense 203
1 Plant Defense Mechanisms 203
2 MLO: A Negative Modulator of Defense Against Powdery Mildew Fungi 205
3 Plant Heterotrimeric G-Protein Signaling and Plant Defense 207
3.1 Heterotrimeric G-Protein Signaling in Rice Defense Responses 208
3.2 Heterotrimeric G-Protein Signaling in Arabidopsis Defense Responses 208
4 MLO: A Putative Plant GPCR? 210
5 Plant Rho-Like Proteins 212
5.1 RAC/ROPs in Disease Resistance and Susceptibility 212
5.2 ROPs and Lipid Rafts 219
6 Perspectives 220
References 220
G Proteins and Plant Innate Immunity 227
1 Introduction 227
2 Heterotrimeric G Proteins and Plant Innate Immunity 228
2.1 Pharmacological Studies 228
2.2 Genetic Studies 231
3 Heterotrimeric G Protein and Plant Cell Death 235
3.1 Function of G Protein in Activation of Oxidative Stress 236
3.2 Regulation of Cell Death by G Proteins 238
4 Innate Immunity Networks Regulated by Heterotrimeric G Proteins 239
5 Small G Proteins in Plant Innate Immunity 243
6 Future Directions 248
References 249
Bioinformatics of Seven-Transmembrane Receptors in Plant Genomes 257
1 Seven-Transmembrane Receptors: Overview 257
1.1 Architecture of the Seven-Transmembrane Receptors 258
1.2 Classification of the Seven-Transmembrane Receptor Superfamily 258
1.3 Seven-Transmembrane Receptors in Plants 262
1.4 Conservation of 7TMR Proteins Among and Between Plants and Animals 263
1.5 Are There More 7TMRs in Plants? 267
2 Bioinformatics Methods for Protein Classification 268
2.1 Pairwise-Alignment- Based Method: BLAST 268
2.2 Conserved Motif Matching Methods 269
2.3 Profile-Based Search Methods 270
2.4 Alignment-Free Methods 273
2.5 Transmembrane Prediction Methods 274
2.6 GPCRHMM 276
3 Mining 7TMR Proteins from Plant Genomes 276
4 Conclusion 279
References 279
Unconventional GTP-Binding Proteins in Plants 284
1 Introduction 284
2 Extra-Large GTP-Binding Proteins 286
2.1 Structural features of Arabidopsis XLGs 287
2.2 XLGs are Plant-Specific Proteins 288
2.3 XLGs are Ubiquitously Expressed Nuclear Proteins 289
2.4 Physiological Processes Regulated by XLGs 290
2.5 How do XLGs Function: Speculations 296
3 Developmentally Regulated GTP-Binding Proteins 296
3.1 Presence of DRGs in Plants 297
3.2 Expression Patterns of Plant DRGs 298
3.3 Biological Functions and Regulatory Mechanisms of Plant DRGs: Still a Mystery 299
4 GPCR-Type GTP-Binding Proteins 300
4.1 Structural and Biochemical Features of GTGs 300
4.2 GTGs are Widely Expressed Plasma Membrane Proteins 301
4.3 GTGs Interact with Arabidopsis GPA1 301
4.4 GTGs mediate Arabidopsis Responses to ABA 301
4.5 GTGs are ABA Receptors 302
5 Conclusions and Perspectives 302
References 303
Evolution of the ROP GTPase Signaling Module 309
1 Introduction 309
2 Composition of the ROP Signaling Module 310
3 The ROP GTPases 3.1 Origin of the ROP GTPases 312
3.2 Diversification in the ROP GTPase Family 314
3.3 Functional Implications of ROP Diversification 321
4 Evolution of ROP Regulators 4.1 Positive Regulators: The RopGEFs 322
4.2 Negative Regulators: RhoGDIs and RopGAPs 324
5 Evolution of Output from the ROP Module 325
6 Conclusions 327
References 328
Index 332

Produkt-Details

• Erscheint lt. Verlag: 25.11.2009
• Reihe/Serie: Signaling and Communication in Plants
• Reihe/Serie: Signaling and Communication in Plants
• Zusatzinfo: X, 336 p. 40 illus., 10 illus. in color.
• Verlagsort: Berlin
• Sprache: englisch
• Themenwelt: Naturwissenschaften ► Biologie ► Botanik
• Themenwelt: Naturwissenschaften ► Biologie ► Mikrobiologie / Immunologie
• Themenwelt: Technik
• Schlagworte: plant cell biology • plant communicatio • Plant Physiology • plant sensory biology • Plant signaling • Protein • proteins • Regulation
• ISBN-10: 3-642-03524-8 / 3642035248
• ISBN-13: 978-3-642-03524-1 / 9783642035241