Abstract:

Microtubules (MTs) are cytoskeletal elements formed by a non-covalent association of α- and β-tubulin heterodimers. They provide structure and shape to all eukaryotic cells and are implicated in a variety of fundamental cellular processes including cell motility, cell division, mechanotransduction as well as long-distance intracellular cargo transport. In neurons, they constitute the molecular frame that maintains the lengthy axonal projections. In view of the relative size of some axons in the human body, which can reach up to 1 m, the active transport of e.g., vesicles over the MT arrays to the synaptic cleft, is of particular importance. Considering the numerous roles of MTs, it is not surprising that already 30 years ago, impairment of the MT-based system was proposed as a unifying hypothesis for the variable clinical presentations in Alzheimer’s disease. In this context, a key question is how the MT network accommodates all these different functions, often within the same cell? Current view is that every MT-dependent process is executed through the recruitment of a specific set of MT-associated proteins (MAPs) and molecular motors. Thus, it is of fundamental importance to understand how recruitment of these MAPs and motors is regulated. Since many of the MAPs and motors bind to the C-terminal tails of α- and β-tubulin, which are known to protrude from the MT surface, one important mechanism by which MTs may regulate the association of the effector proteins is through posttranslational modifications (PTMs).