FIG. 8.

32D cells expressing ΔTrkA contain elevated levels of activated Ras and ERK MAP kinases but do not contain activated Stat5. (A) The level of Ras activation was measured by the Ras glutathione S-transferase–Ras binding domain (GST-RBD) pull-down assay. Bound (active) Ras (Ras-GTP) and total cell lysates of 32D cells expressing vector, TrkA, ΔTrkA, and H-Ras61L were analyzed by Western blotting with anti-pan Ras antibodies. H-Ras61L migrates faster than wild-type endogenous Ras. (B) Cell lysates of 32D cells expressing vector, ΔTrkA, Bcr-Abl, or vector cells stimulated with IL-3 were analyzed by Western blotting with antibodies that recognize activated, phosphorylated ERK MAP kinases. Blots were also analyzed with anti-ERK antibodies. (C) Cell lysates of 32D cells expressing vector, ΔTrkA, Bcr-Abl, or vector cells stimulated with IL-3 were analyzed by Western blotting with antibodies that recognize activated, phosphorylated Stat5. Blots were also probed with anti-Stat5 antibodies. A mobility shift caused by Stat5 phosphorylation can be seen.