title: Tracking of plus-ends reveals microtubule functional diversity in different cell types.
abstract: Many cellular processes are tightly connected to the dynamics of microtubules (MTs). While in neuronal axons MTs mainly regulate intracellular trafficking, they participate in cytoskeleton reorganization in many other eukaryotic cells, enabling the cell to efficiently adapt to changes in the environment. We show that the functional differences of MTs in different cell types and regions is reflected in the dynamic properties of MT tips. Using plus-end tracking proteins EB1 to monitor growing MT plus-ends, we show that MT dynamics and life cycle in axons of human neurons significantly differ from that of fibroblast cells. The density of plus-ends, as well as the rescue and catastrophe frequencies increase while the growth rate decreases toward the fibroblast cell margin. This results in a rather stable filamentous network structure and maintains the connection between nucleus and membrane. In contrast, plus-ends are uniformly distributed along the axons and exhibit diverse polymerization run times and spatially homogeneous rescue and catastrophe frequencies, leading to MT segments of various lengths. The probability distributions of the excursion length of polymerization and the MT length both follow nearly exponential tails, in agreement with the analytical predictions of a two-state model of MT dynamics.
authors.affiliation: Department of Theoretical Physics, Saarland University, 66041 Saarbrücken, Germany.
authors.forename: M Reza
authors.initials: MR
authors.lastname: Shaebani
authors.affiliation: Department of Experimental Physics, Saarland University, 66041 Saarbrücken, Germany.
authors.forename: Aravind
authors.initials: A
authors.lastname: Pasula
authors.affiliation: Department of Experimental Physics, Saarland University, 66041 Saarbrücken, Germany.
authors.forename: Albrecht
authors.initials: A
authors.lastname: Ott
authors.affiliation: Department of Theoretical Physics, Saarland University, 66041 Saarbrücken, Germany.
authors.forename: Ludger
authors.initials: L
authors.lastname: Santen
mesh_terms: D000818:Animals; D002460:Cell Line; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D002467:Cell Nucleus / Q000378:metabolism / Q000648:ultrastructure; D005347:Fibroblasts / Q000378:metabolism* / Q000648:ultrastructure; D015870:Gene Expression; D006801:Humans; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000235:genetics* / Q000378:metabolism; D008870:Microtubules / Q000145:classification / Q000378:metabolism* / Q000648:ultrastructure; D009474:Neurons / Q000378:metabolism* / Q000648:ultrastructure; D009928:Organ Specificity; D058105:Polymerization
chemical_list: C500985:MAPRE1 protein, human; D008869:Microtubule-Associated Proteins