title: Microtubule-associated protein 1B interaction with tubulin tyrosine ligase contributes to the control of microtubule tyrosination.
abstract: Microtubule-associated protein 1B (MAP1B) is the first microtubule-associated protein to be expressed during nervous system development. MAP1B belongs to a large family of proteins that contribute to the stabilization and/or enhancement of microtubule polymerization. These functions are related to the control of the dynamic properties of microtubules. The C-terminal domain of the neuronal alpha-tubulin isotype is characterized by the presence of an acidic polypeptide, with the last amino acid being tyrosine. This tyrosine residue may be enzymatically removed from the protein by an unknown carboxypeptidase activity. Subsequently, the tyrosine residue is again incorporated into this tubulin by another enzyme, tubulin tyrosine ligase, to yield tyrosinated tubulin. Because neurons lacking MAP1B have a reduced proportion of tyrosinated microtubules, we analyzed the possible interaction between MAP1B and tubulin tyrosine ligase. Our results show that these proteins indeed interact and that the interaction is not affected by MAP1B phosphorylation. Additionally, neurons lacking MAP1B, when exposed to drugs that reversibly depolymerize microtubules, do not fully recover tyrosinated microtubules upon drug removal. These results suggest that MAP1B regulates tyrosination of alpha-tubulin in neuronal microtubules. This regulation may be important for general processes involved in nervous system development such as axonal guidance and neuronal migration.
authors: Laboratory of Neurosciences, Millennium Institute for Cell Dynamics and Biotechnology (ICDB), Santiago, Chile.
authors: Elías
authors: E
authors: Utreras
authors: Eva Maria
authors: EM
authors: Jiménez-Mateos
authors: Erick
authors: E
authors: Contreras-Vallejos
authors: Elena
authors: E
authors: Tortosa
authors: Mar
authors: M
authors: Pérez
authors: Sebastián
authors: S
authors: Rojas
authors: Lorena
authors: L
authors: Saragoni
authors: Ricardo B
authors: RB
authors: Maccioni
authors: Jesús
authors: J
authors: Avila
authors: Christian
authors: C
authors: González-Billault
mesh_terms: D000818:Animals; D001665:Binding Sites; D002454:Cell Differentiation / Q000502:physiology; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000502:physiology; D002490:Central Nervous System / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D005260:Female; D020439:Growth Cones / Q000378:metabolism / Q000648:ultrastructure; D051379:Mice; D008822:Mice, Transgenic; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism* / Q000648:ultrastructure; D009474:Neurons / Q000378:metabolism* / Q000648:ultrastructure; D010453:Peptide Synthases / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000502:physiology; D014404:Tubulin / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism*
chemical_list: D008869:Microtubule-Associated Proteins; D014404:Tubulin; C085284:microtubule-associated protein 1B; D014443:Tyrosine; D010453:Peptide Synthases; C023213:tyrosyltubulin ligase