title: Microtubule-associated protein 1B (MAP1B) is required for dendritic spine development and synaptic maturation.
abstract: Microtubule-associated protein 1B (MAP1B) is prominently expressed during early stages of neuronal development, and it has been implicated in axonal growth and guidance. MAP1B expression is also found in the adult brain in areas of significant synaptic plasticity. Here, we demonstrate that MAP1B is present in dendritic spines, and we describe a decrease in the density of mature dendritic spines in neurons of MAP1B-deficient mice that was accompanied by an increase in the number of immature filopodia-like protrusions. Although these neurons exhibited normal passive membrane properties and action potential firing, AMPA receptor-mediated synaptic currents were significantly diminished. Moreover, we observed a significant decrease in Rac1 activity and an increase in RhoA activity in the post-synaptic densities of adult MAP1B(+/-) mice when compared with wild type controls. MAP1B(+/-) fractions also exhibited a decrease in phosphorylated cofilin. Taken together, these results indicate a new and important role for MAP1B in the formation and maturation of dendritic spines, possibly through the regulation of the actin cytoskeleton. This activity of MAP1B could contribute to the regulation of synaptic activity and plasticity in the adult brain.
authors: Department of Neuroscience, Centro de Biología Molecular Severo Ochoa CSIC/UAM, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
authors: Elena
authors: E
authors: Tortosa
authors: Carolina
authors: C
authors: Montenegro-Venegas
authors: Marion
authors: M
authors: Benoist
authors: Steffen
authors: S
authors: Härtel
authors: Christian
authors: C
authors: González-Billault
authors: Jose A
authors: JA
authors: Esteban
authors: Jesús
authors: J
authors: Avila
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism; D000818:Animals; D049229:Dendritic Spines / Q000378:metabolism*; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000172:deficiency / Q000378:metabolism*; D013569:Synapses / Q000378:metabolism*; D020830:rac1 GTP-Binding Protein / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
chemical_list: D008869:Microtubule-Associated Proteins; C085284:microtubule-associated protein 1B; D020830:rac1 GTP-Binding Protein; D020742:rhoA GTP-Binding Protein