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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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Membraneless organelles - physiological functions and experimental techniques of their study
Bašta, Miroslav ; Bařinka, Cyril (advisor) ; Humhalová, Tereza (referee)
Membraneless organelles, also called biomolecular condensates or protein droplets, are liquid spheric bodies present in an every cell compartment. Their composition and density is only slightly different from their surroundings. They consist of hundreds of types of proteins and nucleic acids and they are responsible for various biological functions. They are formed via liquid-liquid phase separation that creates a phase boundary in a solution of macromolecules in order to decrease the low free energy of the system. This process is initiated by external stress, internal cell processes or mutations in DNA. There are many identified types of membraneless organelles and each year there are more added on the list. Their functions include localization of macromolecules and related biochemical reactions, tuning of biochemical reactions and transport of macromolecules throughout the cell. This thesis presents a brief summary of the topic of membraneless organelles with several specific examples and very briefly describes several selected methods of their study.
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