Differences on the Effect of Proteins of the Same Tethering Complex on Neuronal Polarity

Congreso; XXXIII CONGRESO ANUAL SAN 2018 CORDOBA ARGENTINA; 2018

Sociedad Argentina de Neurociencia

The initial signals that determine polarity are largely unknown, placing the mechanisms underlying the axon formation under the scope of our investigation. Two interconnected process are essential for axon formation: the axonal biochemical specification and the rapid membrane outgrowth. The exocytic pathways that function to translocate membrane patches to plasma membrane undergoes by regulated nonsecretory exocytoses. It has been shown in hippocampal neurons that the axolemmal expansion occurs by the insertion of plasmmalemal precursor vesicles (PPVs) at the growth cone, a process regulated by IGF1. A previous physical interaction between the vesicle target and the membrane is necessary to fusion. This process is mediated by thethering complexes. The exocyst complex is a candidate for the regulation of fusion of PPVs of which the total composition is still unknown in neurons. It has been reported that IGF-1 triggers translocation to the plasma membrane of the exocyst component exo70 in the growth cone, being one of the steps at the complex formation. We determined that several proteins of the exocyst complex are present at hippocampal cultures in early stages of development. Moreover, two proteins of this complex have opposites effects on neuronal differentiation. The implication of silencing sec3 in hippocampal cultures and in utero electroporation develops abnormalities. In constrast, the effect of suppressing sec8 remains neuronal migration and polarity nonaffected.