Fig. 7.

Axons promote Schwann cell survival via contact-dependent signals that require PI 3-kinase. Schwann cells were cultured for 2 d in either serum-containing media (Ctrl) or serum-free media (SFM). In some cultures, the serum-free media were supplemented by centrifuging two aliquots of neurite membranes at 24 hr intervals, without (mb) or with 20 μm LY294002 (LY20) or 10 μmU0126 (U10). Apoptotic cells were detected by the TUNEL assay. Values represent the mean BrdU index ± SEM from two separate experiments.