Figure 4: NRG-1 increases mRNA level of megalin. (a) NRG-1 (1 nM) increased total Cbl level in SH-SY5Y cells and this stimulatory effect was blocked by pretreatment with the PI3 kinase inhibitor wortmannin (100 nM), . Total Cbl was calculated by summing individual Cbl values presented in Figure 1. (b) NRG-1 (1 nM) increased the mRNA level of megalin. . Data represent mean values ± SEM. Asterisks () indicate a significant difference () from control group. # indicates a significant difference () from NRG-1 treated group.