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Tubulin post-translational modifications and microtubule associated proteins in neural development and disease.
Belyaeva, Polina ; Balaštík, Martin (advisor) ; Siahaan, Valerie (referee)
Microtubules (MTs) are essential components of the cytoskeleton in all eukaryotic cells. Their function is particularly important in neurons where MTs stabilize their long processes and are responsible for the precisely regulated anterograde and retrograde, intra-axonal and intra- dendritic transport over long distances. MTs are essential also during development of the vertebrate brain and all its major steps: neurogenesis, neuronal migration and neuronal differentiation. MTs are regulated at multiple levels, but two seem to be particularly important: 1. posttranslational modifications of tubulin (PTMs) have been shown to control several MT properties as stability or MT-based transport. 2. microtubule-associated proteins (MAPs) that bind soluble MT subunits, MT lattice as well as MT ends and control MT-based transport and MT dynamics by either stabilizing, destabilizing or severing MTs. Consequently, deregulation of either tubulin PTMs or MAPs may induce severe changes in neuronal cytoskeleton. Bachelor's thesis summarizes current knowledge on how PTMs (especially polyglutamylation) and MAPs (especially microtubule cleaving proteins such as spastin) regulate MT and neuronal development and degeneration. Keywords: Microtubules, tubulin post-translational modifications, polyglutamylation,...
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Polyglutamylation as a Posttranslational Tubulin Modification
Bašta, Miroslav ; Bařinka, Cyril (advisor) ; Dráber, Pavel (referee)
α-tubulin is an essential protein for every eukaryotic cell. Together with β-tubulin, it polymerises into microtubules and participates thus in creating and maintaining cellular structures and presents a cell-wide interaction platform for a plethora of microtubule associating proteins. Primary sequences of the disordered C-termini of both α- and β-tubulin are the least conserved among tubulin isotypes and their variability is further increased by the presence of various post-translational modifications. The genetically coded, tyrosinated C-terminus of α-tubulin can be either shortened by one, two or three amino acids resulting in detyrosinated, Δ2, or Δ3 variants, respectively or it can be extended by the addition of polyglutamate or polyglycine chains. The tubulin tyrosine ligase-like (TTLL) protein family consists of 14 enzymes that participate in tubulin glutamylation, glycylation, and tyrosination. The glutamylases have two distinct activities, initiation and elongation of the polyglutamate chain. Initiases link the first glutamate residue to the γ-carboxyl group of one of the glutamates of tubulin C-termini to create a fork in the amino acid sequence. Elongases then recognise the branching glutamate and build up the polyglutamate sidechain one residue at the time. TTLL11 is an elongase of...
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