The TC10-exo70 complex is essential for membrane expansion and axonal especification in developing neurons

SEBASTIÁN DUPRÁZ; DIEGO GRASSI; MARÍA EUGENIA BERNIS; LUCAS SOSA; MARIANO BISBAL; LAURA GASTALDI; IGNACIO JAUSORO; ALFREDO CÁCERES; KARL H. PFENNINGER; SANTIAGO QUIROGA

SOC NEUROSCIENCE

Lugar: Washington DC; Año: 2009 vol. 29 p. 13292 - 13292

p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 35.4pt; LINE-HEIGHT: 200%; TEXT-ALIGN: justify">Axonal elongation is one of the hallmarks of neuronal polarization. This phenomenon requires axonal membrane growth by exocytosis of plasmalemmal precursor vesicles (PPVs) at the nerve growth cone, a process regulated by IGF-1 activation of the PI3k pathway. Few details are known, however, about the targeting mechanisms for PPVs. Here we show, in cultured hippocampal pyramidal neurons and growth cones isolated from fetal rat brain, that IGF-1 activates the GTP-binding protein TC10, which triggers translocation to the plasma membrane of the exocyst component exo70 in the distal axon and growth cone. We also show that TC10 and exo70 function are necessary for addition of new membrane and, thus, axon elongation stimulated by IGF-1. Moreover, expression silencing of either TC10 or exo70 inhibit the establishment of neuronal polarity