About this Research Topic
Microtubules (MT) are cylindrical, intracellular, protein polymers formed by the linear and polar assembly of a/b tubulin heterodimers. MT do not form randomly and are not distributed randomly once formed. Rather, they organize in arrays characterized by degree of uniformity of translational orientation and of polarity throughout their three-dimensional organization. Cells may contain more than one array. In the brain, microtubules are abundant in neurons, aligning and stabilizing axons and dendrites as paraxially aligned arrays. These microtubule arrays provide a structural base for axons and dendrites that allows them to acquire and stabilize their specialized morphologies.
Notably, MT biology is driven by arrays, not by single MT, as interesting and informative as single MT are. The characteristics of these arrays and the emergent properties that they generate, are the subject of this Research Topic.
Single MT. Emergent properties are found at each level of added complexity. Single MT physical properties can be altered through plasticity of the microtubule wall lattice, due to incorporation of different tubulin isotypes, posttranslational modifications, nucleotide states, etc. In addition to the MT wall, the MT surface allows collective ionic properties through the ion clouds surrounding the carboxy terminal “tail” peptides protruding from the outer MT surface. The lattice and tails also allow for possible energy migration along the MT.
MT networks. Once formed, MT interact with each other in free solution, forming networks due to MT rigidity and charge, tuned by depletion forces and by reactive processes such as reaction-diffusion coupling. Upon addition of MT motor proteins such as kinesins, these networks can show elaborate collective dynamics such as flocking.
MT arrays. When these MT networks are contained within a cell with the myriad other proteins that comprise cellular MT, the resulting MT arrays show a relatively limited number of possible organizations (e.g., radial, co-polar-parallel, co-polar-orthogonal, anti-polar, etc.). These arrangements can give rise to largescale directional transport and cell polarity. The organization of microtubule arrays in the cells is critically important for the healthy operating of the different cellular systems. For instance, in many neurodegenerative diseases, there is a gradual loss of microtubule mass from neurons.
How do the emergent properties of single MT combine in arrays? Is this influenced by the overall geometry? This Research Topic collection will seek articles that employ diverse approaches including (but not limited to) biochemistry, biophysics, advanced imaging, and modeling to explore the emergent properties of MT at the levels of single MT, MT networks, and especially MT arrays, constrained by the geometries found in different types of cells. In addition, how single MT effects, such as those induced by MT-targeting drugs, can amplify through the arrays, will be a topic of interest.
Notably, MT biology is driven by arrays, not by single MT, as interesting and informative as single MT are. The characteristics of these arrays and the emergent properties that they generate, are the subject of this Research Topic.
Single MT. Emergent properties are found at each level of added complexity. Single MT physical properties can be altered through plasticity of the microtubule wall lattice, due to incorporation of different tubulin isotypes, posttranslational modifications, nucleotide states, etc. In addition to the MT wall, the MT surface allows collective ionic properties through the ion clouds surrounding the carboxy terminal “tail” peptides protruding from the outer MT surface. The lattice and tails also allow for possible energy migration along the MT.
MT networks. Once formed, MT interact with each other in free solution, forming networks due to MT rigidity and charge, tuned by depletion forces and by reactive processes such as reaction-diffusion coupling. Upon addition of MT motor proteins such as kinesins, these networks can show elaborate collective dynamics such as flocking.
MT arrays. When these MT networks are contained within a cell with the myriad other proteins that comprise cellular MT, the resulting MT arrays show a relatively limited number of possible organizations (e.g., radial, co-polar-parallel, co-polar-orthogonal, anti-polar, etc.). These arrangements can give rise to largescale directional transport and cell polarity. The organization of microtubule arrays in the cells is critically important for the healthy operating of the different cellular systems. For instance, in many neurodegenerative diseases, there is a gradual loss of microtubule mass from neurons.
How do the emergent properties of single MT combine in arrays? Is this influenced by the overall geometry? This Research Topic collection will seek articles that employ diverse approaches including (but not limited to) biochemistry, biophysics, advanced imaging, and modeling to explore the emergent properties of MT at the levels of single MT, MT networks, and especially MT arrays, constrained by the geometries found in different types of cells. In addition, how single MT effects, such as those induced by MT-targeting drugs, can amplify through the arrays, will be a topic of interest.
Keywords: Collective dynamics, cell polarity, hierarchical complexity, emergent mechanics, self-organization
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