Figure 8.

N-cadherin-dependent spine enlargement requires kalirin. a, Overexpression of myc-kalirin-7 (kal7 expressing) prevents the formation of long and thin spines induced by interference with N-cadherin adhesion (interf Ab); nontransfected neurons still form these spines. Cortical neurons were immunostained for GFP and myc. b, Magnified images of dendrites of neurons untreated (control), or treated with interfering antibody (interf Ab) with or without myc-kalirin-7 expression; cells immunostained as above. c, Quantification of spine lengths, areas, and linear densities (*p < 0.05 compared with control). d, Kalirin-7 knockdown by 3 d RNAi treatment prevents N-cadherin-induced spine enlargement; expression of an RNAi-insensitive kalirin-7 mutant rescues this effect (**p < 0.01 compared with control; ***p < 0.001 compared with kal7 RNAi or kal7 RNAi plus kal7 rescue). e, Overexpression of kal7-ΔGEF prevents spine enlargement induced by N-cadherin activation. Error bars indicate SEM. Scale bars: a, b, 10 μm; e, 5 μm.