Figure 9.

Pak1 activation is required for NCAM-dependent neurite outgrowth. A, B, Diagrams show mean + SEM lengths of the longest neurite (A) or total lengths of all neurites (B) per neuron (n = 100 neurons were analyzed in each group). Cultured cortex neurons from NCAM+/+ mice were transfected with the empty pCGC vector, constitutively active pCGC-CA-Pak1, or dominant-negative pCGC-DN-Pak1. Neurons were treated with NCAM antibodies or nonimmune serum applied 6 h after transfection for 24 h. Note increased response to NCAM antibodies in pCGC-CA-Pak-transfected neurons. Note that pCGC-DN-Pak1-transfected neurons do not respond to function-triggering NCAM antibodies. *p < 0.05, t test.