FIG. 2.

Survival of 32D cells expressing wild-type (WT) and mutant IGF-1R. 32D cells were stably transduced with retroviral vectors expressing the indicated receptors (see also Table 1), and survival was determined at 24 h (A) and 48 h (B) after IL-3 withdrawal. FBS+IGF-1, 10% FBS plus IGF-1 (50 ng/ml), no IL-3; FBS, 10% fetal bovine serum, no IGF-1 or IL-3. The behavior in FBS supplemented with IL-3 was omitted since all cell lines grew vigorously in this medium. mut., mutation; del., deletion. (C) Western blots for the IGF-1R of the cell lines used in panels A and B. In all instances, we used an antibody to the C terminus of the IGF-1R (see Materials and Methods), except for GR36, that is truncated at residue 1245. For this receptor, we used an antibody to the α subunit. (D) Staining for DNA. (E) TUNEL staining. The upper figures are for the GR18 mutant; the lower figures are for the GR15 cells (wild-type receptor).