Figure 2.

Regulation of PDK1 during rat cortical development. A, B, At P1, P7, and P21, both total PDK1 and phospho-Ser-241 PDK1 were detected by Western blotting of lysates from rat cortex. Note that the pSer241-PDK1/total PDK1 ratio remained similar at all developmental stages examined. In contrast, the PDK1-mediated phosphorylation of RSK1/2 Ser221/227 decreased over the studied ages. Thus, PDK1-RSK1/2 signaling is active in developing forebrain during synaptogenesis when neurons are highly dependent on extracellular survival signals. At P1 and P7, electromobility of total or pSer241 PDK1 was lower than at P21, indicating possible hyperphosphorylation at non-Ser241 sites. In A, same amounts of protein lysates were analyzed in each lane. In B, data represent averages of three animals at each developmental stage ±SEM; the pSer241 PDK1 or pSer221/227 RSK1/2 levels were normalized against total PDK1 or RSK1/2, respectively. *p < 0.05.