The Plant Cytoskeleton (eBook)

Bo Liu is professor in the Department of Plant Biology at the University of California in Davis, California. He received his B.S. degree in cell biology and genetics and M.S. degree in cell biology from Peking University in Beijing, China, and Ph.D. degree in botany from the University of Georgia in Athens, Georgia. Research in his laboratory is focused on studying the cytoskeletal basis of intracellular motility in flowering plants and filamentous fungi.

Preface 6
Contents 8
Contributors 10
Part I Molecular Basis of the Plant Cytoskeleton 14
Chapter 1: Actin Functions in the Cytoplasmic and Nuclear Compartments 15
1.1 Introduction 15
1.2 Evolutionary Origin and Phylogeny of Plant Actins and Actin Binding Proteins 16
1.3 The Actin Cytoskeleton in Plant Cell Polarity and Elongation 19
1.3.1 Genetic Studies Demonstrate the Role of Actin and ABP Variants in Cell Polarity and Elongation 19
1.3.2 F-Actin Filament Dynamics and Cell Elongation 22
1.3.3 Protein Variant Differences vs. Gene Regulation 25
1.3.4 Protein–Protein Interactions Among Actin and ABP Families 28
1.3.5 Organelle Streaming and Vesicle Movement Within a Relatively Stationary Cytoplasm 29
1.4 Nuclear Actin 31
1.4.1 History of Nuclear Actin Research 31
1.4.2 Plant Actin and ABPs in the Nucleus 31
1.4.3 Molecular Genetic Functions of Nuclear Actin 33
1.4.4 Epigenetic Functions for Actin in the Assembly of Chromatin Remodeling and Modifying Complexes 33
1.5 Actins and ADFs in Signal Transduction 35
References 37
Chapter 2: Plant Myosins 45
2.1 Introduction 45
2.2 Domain Structures of Plant Myosin Heavy Chains 47
2.3 The Motor Domain 48
2.4 The Directional Determinant of Organelle Transport by the Polarity of Acitn Filaments 49
2.5 The Neck Domain 50
2.6 a-Helical Coiled-Coil Domain in the Tail Region 51
2.7 Processive Movement of Higher Pant Myosin XI 53
2.8 Regulation of Higher Plant Myosin XI Through CaM Light Chain 54
2.9 Regulation of Cytoplasmic Streaming or Organelle Transports in Pollen Tubes 55
2.10 Globular Tail Domain 55
2.11 The Mechanism for Cargo Recognition by Higher Plant Myosin XI 56
2.12 Functional Inter-Domain Communication Between a-Helical Coiled-Coil and Globular Tail Domains 58
2.13 Direct Binding of Chara Myosin XI to Phospholipid Vesicles 59
2.14 Cytoplasmic Streaming in Characean Cells 59
2.15 The Regulation of Cytoplasmic Streaming in the Characean Cell 60
2.16 Cytoplasmic Streaming in Higher Plant Cells 61
2.17 Conclusion 62
References 63
Chapter 3: Actin-Binding Proteins and Actin Dynamics in Plant Cells 69
3.1 Introduction 70
3.2 Profilin 71
3.3 Arp2/3 Complex and Its Regulatory WAVE Complex 73
3.4 Formin 75
3.5 Capping Protein (CP) 77
3.6 Actin Depolymerizing Factors (ADFs) 78
3.7 Villin/Gelsolin/Fragmin Superfamily Proteins 80
3.8 Conclusions 83
References 84
Chapter 4: Microtubule Nucleation and Organization in Plant Cells 93
4.1 Introduction 93
4.2 Microtubule Nucleation Sites in Land Plant Cells 93
4.2.1 Patterns of Microtubules in the Cell Cycle of Land Plants 93
4.2.2 Microtubule Nucleation in Interphase Cells 95
4.2.2.1 Nucleation Sites for the Cortical Array 95
4.2.2.2 Nucleation Sites for the Radial Array 96
4.2.3 Microtubule Nucleation for Preprophase Band Development 96
4.2.4 Microtubule Nucleation in Mitosis 97
4.2.4.1 Three Pathways in Metazoan Cells 97
4.2.4.2 Origin of Spindle Microtubules at Prophase 98
4.2.4.3 Microtubule Nucleation Sites During Spindle Development 98
4.2.5 Microtubule Nucleation in Cytokinesis 99
4.3 Proteins Involved in Microtubule Nucleation 99
4.3.1 g-Tubulin Complexes 99
4.3.2 Other Centrosomal Proteins 100
4.3.3 Is There g-Tubulin-Independent Nucleation? 101
4.4 Role of Microtubule Nucleation in Microtubule Organization 101
4.5 Concluding Remarks 102
References 103
Chapter 5: Microtubule Plus End-Tracking Proteins and Their Activities in Plants 107
5.1 Introduction 107
5.2 Microtubule Structure and Dynamics 109
5.3 Holding onto a Moving Target: How +TIPs Find, Recognize and Maintain Contact with the Plus End 110
5.4 +TIPs and Their Role in the Cell 112
5.5 +TIPs in Plants 112
5.6 EB1, the Quintessential +TIP 114
5.7 Structural Conservation Amongst EB1 Family Members 114
5.8 EB1 Localization Patterns in Plant Cells 115
5.9 EB1 and the Regulation of Microtubule Dynamics 116
5.10 EB1 and +TIP Complex Assembly 117
5.11 Proteins Bearing TOG Domains: MOR1 and CLASP 118
5.12 Plant Kinesins and ATK5 119
5.13 Actin-Related Proteins 121
5.14 Plant-Specific +TIPs 121
5.15 Conclusions and Unanswered Questions 122
References 123
Chapter 6: Microtubule Motor Proteins in the Eukaryotic Green Lineage: Functions and Regulation 130
6.1 Introduction 130
6.2 Kinesins 131
6.3 Kinesin Types and Evolutionary Relationships 131
6.4 Domains in Kinesins 138
6.5 Known Functions of Kinesins in Plants 140
6.6 Structure and Regulation of Kinesins 145
6.7 Concluding Remarks 148
References 148
Part II Cytoskeletal Reorganization in Plant Cell Division 153
Chapter 7: The Preprophase Band and Division Site Determination in Land Plants 154
7.1 Introduction 154
7.1.1 Focus of this Chapter 154
7.1.2 What is a PPB? 155
7.1.3 To Have or Not to Have a PPB 156
7.1.4 The PPB in Evolution 156
7.2 The PPB and the Cell Cycle 157
7.2.1 A Coupling Between Cell Cycle and PPB Formation? 157
7.2.2 The Cell Cycle and G2/M Transition 157
7.2.2.1 Cyclin-Dependent Kinases 160
7.2.2.2 Cyclins 160
7.2.2.3 CDK Inhibitors 160
7.2.2.4 CKS Proteins 161
7.2.2.5 Regulation of CDK Complexes by Phosphorylation 161
7.2.3 Core Cell Cycle Proteins Identified at the PPB 161
7.3 The PPB and the Pre-Mitotic Cell 163
7.3.1 The Nucleus 163
7.3.2 Vacuoles and the Phragmosome 164
7.3.3 Golgi Apparatus and Endocytosis 165
7.4 Structure and Dynamics of the PPB 165
7.4.1 Microtubules 165
7.4.1.1 MT Dynamics at the Cortex 166
7.4.1.2 Origin and Dynamics of PPB Microtubules 166
7.4.1.3 Non PPB Microtubules During the G2/M Transition 167
7.4.2 Actin 169
7.4.3 Proteins Localized to the PPB: A Critical Review 170
7.4.3.1 Preliminary Remarks 170
7.4.3.2 Proteins Potentially Involved in PPB Formation 170
7.4.3.3 Proteins Potentially Involved in CDS Establishment 178
7.5 The PPB and the Division Plane of Plant Cells 179
7.5.1 Introduction 179
7.5.2 Mutations Affecting the PPB 179
7.5.3 The PPB and Cortical Division Site Establishment 183
7.5.4 The PPB and the Prophase Spindle 184
7.6 Conclusions 185
References 186
Chapter 8: Acentrosomal Spindle Formation Through the Heroic Age of Microscopy: Past Techniques, Present Thoughts, and Future Directions 195
8.1 Early Fixation Techniques 196
8.2 Light Microscopy Techniques 198
8.3 Transmission Electron Microscopy (TEM) Techniques 200
8.4 Fluorescence Microscopy: Immunofluorescence 202
8.5 Fluorescent Microscopy Techniques: Intrinsic Fluorescent Proteins 205
8.6 Acentrosomal Bipolarity Organized by the PPB 208
8.7 The Future Directions in Acentrosomal Spindle Formation 209
References 210
Chapter 9: Microtubule Organization in the Phragmoplast 214
9.1 Introduction 214
9.2 Microtubule-Interacting Factors in the Phragmoplast 216
9.3 Organization of Microtubule Minus Ends in the Phragmoplast 221
9.4 Organization of Microtubule Plus Ends in the Phragmoplast 222
9.5 Stability and Turnovers of Microtubules in the Phragmoplast 223
9.6 Regulation of Phragmoplast MT Dynamics by Post-Translational Modifications 224
9.7 Conclusion: Assembly of the Phragmoplast by Mini-Phragmoplasts 225
References 226
Part III The Cytoskeleton in Plant Growth and Development 233
Chapter 10: Signaling to the Cytoskeleton in Diffuse Cell Growth 234
10.1 Signals Modulating Diffuse Cell Growth 235
10.1.1 Phytohormones 235
10.1.2 Mechanical Signals 237
10.2 Signal Transduction Pathways Regulating MFs 238
10.3 Signal Transduction Pathways that Transmit Signals to MTs 240
10.3.1 ROP GTPase Signaling 241
10.3.2 Protein Kinases and Phosphatases 242
10.3.2.1 Perspective 242
References 243
Chapter 11: Microtubule and Cell Shape Determination 249
11.1 Microtubules Determine Cell Shape 249
11.2 Distinct MT Array Organization Correlates with Cell Shape: Wild-Type Cells 250
11.3 Helical Growth as an Unusual Case of Growth Anisotropy 251
11.4 Helical MT Organization Underlies Skewed Cell Growth 254
11.5 Toward Elucidation of Symmetry-Breaking Factors 256
11.6 Tissue Morphology Affects Microtubule Alignment 258
References 259
Chapter 12: Cytoskeleton and Root Hair Growth 262
12.1 Introduction 262
12.2 Root Hair Initiation 263
12.2.1 Selection of the Bulge Site 263
12.2.2 The Cytoskeleton in Bulge Formation 264
12.3 Root Hair Tip Growth: General Considerations and Organelle Distribution 265
12.3.1 Actin Cytoskeleton in Root Hair Tip Growth 265
12.3.2 Myosin in Root Hair Tip Growth 267
12.3.3 Microtubules and Root Hair Tip Growth 268
12.3.4 Membrane Trafficking and Tip Growth 269
12.3.5 Signaling Factors in Tip Growth 271
12.4 Conclusions 272
References 274
Chapter 13: Microtubules, MAPs and Xylem Formation 279
13.1 Introduction 279
13.2 Microtubule Organization in Xylem Cells 282
13.3 Impact of Pharmacological Treatments on Microtubules in Xylem Cells 288
13.4 Reorientation of the Microtubule Network Axis During Xylem Cell Formation 291
13.5 Expression of Microtubule and MAP Genes During Xylem Formation 292
13.5.1 Tubulin During Xylem Formation 292
13.5.2 MAP70 Microtubule Associated Protein During Xylem Vessel Formation 293
13.5.3 MIDD1 Microtubule Plus-End Associated Protein During Xylem Vessel Formation 294
13.5.4 The Cross-Bridging MAP65 During Xylem Vessel Formation 296
13.5.5 FRA1 Kinesin During Xylem Cell Wall Formation 297
13.5.6 FRA2 Katanin During Xylem Cell Wall Formation 299
13.5.7 MAP20s During Xylem Cell Wall Formation 299
13.6 Microtubules and Cellulose Synthesis in Xylem Cells 299
13.7 Microtubules and the Global Patterning of the Xylem Cell Wall 300
13.8 Conclusion 302
References 303
Chapter 14: The Cytoskeleton and Root Growth Behavior 309
14.1 Introduction 309
14.2 Roots Grow Using a Combination of Cell Division and Cell Expansion 312
14.2.1 Controlled Cell Division Contributes to Root Growth 312
14.2.2 Regulated Cell Expansion Also Contributes to Root Growth 313
14.3 Mutations in Tubulin Genes Affect Microtubule Arrays and Root Skewing 314
14.4 Mutations in Microtubule Associated Proteins Also Lead to Abnormal Root Development 315
14.5 Other Mutations that Alter Root Growth Behavior 319
14.6 Natural Variation in Root Growth Behavior 322
14.7 Closing Remarks 324
References 324
Index 329