INIMEC - CONICET   05467
INSTITUTO DE INVESTIGACION MEDICA MERCEDES Y MARTIN FERREYRA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Efecto de la fosforilación de TIAM1 en el desarrollo dendrítico
Autor/es:
FARÍAS GIMENA; GASTALDI LAURA; REMEDI MÓNICA; CÁCERES ALFREDO
Lugar:
Huerta Grande-Cordoba
Reunión:
Congreso; XXV Reunión Anual de la Sociedad Argentina de Investigación en Neurociencias; 2010
Institución organizadora:
Sociedad Argentina de Investigación en Neurociencias
Resumen:
AbstractThe antagonist relationship between Rho and Rac is essential for the establishment of cell polarity. RhoGTPases activity is controlled by GEFs. Tiam1/2 are Rac GEFs that interact with Par3. The overexpression of Tiam1/2 induces multiple axon for­mation while its suppression prevents axon outgrowth. In non-neural cells, RhoK (a downstream effector of Rho) phosphorylates Tiam1 / 2, preventing its associa­tion with Par3 and the formation of the polarity complex Par3-Par6-aPKC. In this study we evaluated the effect of Tiam1 mutants mimicking RhoK phosphorylation on dendritic development. To this end, site-directed mutagenesis was performed to generate Tiam1/2 mutants on consensus sequence for Rho-kinase. Thus, by repla­cing the target residue by alanine (Tiam1-AA), a mutant was generated that can not be phosphorylated by RhoK, while substitution by glutamic (Tiam1-EE) result in a mutant that emulates RhoK induced phosphorylation. Primary cultures of hippo­campal neurons were transfected with each construct to evaluate the effect of these mutants on neuronal morphology. Confocal microscopy revealed that the phospho­mimic mutant (Tiam1-EE) inhibits dendritic growth, while both Tiam1 wild type and Tiam1-AA stimulate dendritic growth and branching, as well as the subcellular dis­tribution of the axonal marker Tau. Pull-down assay were employed to assess the ability of each mutant to interact with Par3. The results obtained show that the phos­phomimic mutant has a decreased ability to interact with Par3.presentación poster