Microtubules, biological function

The molecular basis for the association between apoE4 and Alzheimer s disease is not yet known. Speculation has focused on a possible role for apoE in stabilizing the cytoslceletal structure of neurons. The apoE2 and apoE3 proteins bind to a number of proteins associated with neuronal microtubules, whereas apoE4 does not. This may accelerate the death of neurons. Whatever the mechanism proves to be, these observations promise to expand our understanding of the biological functions of apolipoproteins. 

Abstract Tubulin is a fascinating molecule that forms the cytoskeleton of the cells and plays an important role in cell division and trafficking of molecules. It polymerizes and depolymerizes in order to fulfill this biological function. This function can be modulated by small molecules that interfere with the polymerization or the depolymerization. In this article, the structural basis of this behavior is reviewed with special attention to the contribution of NMR spectroscopy. Complex structures of small molecules that bind to tubulin and microtubules will be discussed. Many of them have been determined using NMR spectroscopy, which proves to be an important method in tubulin research. 

Hyams JS, Lloyd CW. Microtubules. 1993. WUey-Liss Inc., New York. Advances in microtubule biology are described in detail. In depth coverage of microtubule dynamics and functions in cells is included. 

The multiscale system also appears to be capable of providing more enhanced biological functionality, particularly for vascularization, which is favored by the interaction of ECs with the nanofibrous network.s that allow suitable cell architecture and orientation for microtubule formation. Thus, the synergistic effect of micro- and nanoscales could successfully regenerate natural tissues in vivo in the near future. Future work should focus on optimizing this process to better recapitulate key features of the native ECM, including its mechanical and biochemical properties, which would enhance the functionality of these 3D multiscale scaffolds in order to fabricate functional tissue engineered constructs. 

Transient PPIs are many and varied. The enumeration of their involvement in so many vital biological functions has reached daunting levels. There are thus many examples, including the recruitment and assembly of the transcription complex, protein transport across membranes, chaperonin-catalyzed protein folding, and the recycling of subcellular structures during the cell cycle. Such recycling includes that of microtubules, the spindle apparatus, the nuclear pore complex, and the nuclear lamina. 

Sakai, H. Borisy, G. and Mohri, H. (1982) Biological Functions of Microtubules and Related Structures, New York Academic Press. 

Ferroelectricity is a requirement for some biopolymers for their biological function. Microtubules which hold the cell structurally intact are a good example. These biostructures consist of identical a and (3 tubulin proteins which have permanent dipole moments. Since cells utilize microtubules... 

Figure 1. Top Turbidity, measured at 350 nm, as a function of microtubule polymer mass concentration (expressed as mg/mL polymerized tubulin). Tubulin solutions of varying concentrations were polymerized until they reached stable plateau values in a Cary 118C spectrophotometer. Each sample was then transferred to an ultracentrifuge tube, and microtubules were pelleted, separated from the unpolymerized tubulin in the supernatant fraction, and then resuspended for protein concentration determination. The corresponding turbidity and polymer mass concentrations are plotted here. Bottom Time-course of tubulin polymerization assayed by turbidity.Repro-duced from MacNeal and Purich with permission from the American Society for Biochemistry and Molecular Biology.

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