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.
Highlights
Microtubule-associated protein 1B (MAP1B) is a protein that is prominently expressed during early neuronal development but in adult brain remains in areas with high synaptic plasticity
MAP1B Is Present in Dendritic Compartments of Mature Neurons—The presence and distribution of MAP1B in adult brain was analyzed by immunofluorescence in brain slices from wild type mice
MAP1B is predominantly expressed during neuronal development, strong expression is maintained in adult brain regions that exhibit a high degree of plasticity [8, 61, 62]
Summary
Microtubule-associated protein 1B (MAP1B) is a protein that is prominently expressed during early neuronal development but in adult brain remains in areas with high synaptic plasticity. MAP1B؉/؊ fractions 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. 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. Based on the activity of MAP1B as a scaffold protein [35,36,37], its interaction with actin filaments [36, 38], and the recently described role of MTs in dendritic spine development, we postulated that MAP1B may be involved in regulating the morphogenesis and plasticity of postsynaptic elements. We demonstrate here that MAP1B plays an important role in dendritic spine formation and synaptic maturation by regulating of actin cytoskeleton
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
