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