Skip to main content
. 2012 Jun;180(6):2462–2478. doi: 10.1016/j.ajpath.2012.02.028

Figure 6.

Figure 6

Hyperactivation of signaling pathway kinases upstream of ERK results in Lamγ2 dysregulation in normal keratinocytes. A: Lamγ2 immunostaining of confluent cultures of N/TERT-1 keratinocytes engineered to express constitutively active HRAS(G12V), cRAF1(22w), or MEK1(DD), and EGFRΔ(E746-A750)-FLAG. Scale bar = 200 μm. B: Western blot analysis of Lamγ2, signaling pathway phosphoproteins, and activation state of translation initiation factors of the same cell lines. Control indicates N/TERT-1 cells. Note that expression of constitutively active HRAS, cRAF1, or MEK1 increased p-ERK, p-S6, and p-eIF4B levels, whereas constitutively active EGFR slightly increased levels of p-ERK, robustly increased p-S6, but did not increase p-eIF4B and did not cause Lamγ2 overexpression. C: Western blot analysis of effects of EGFR and MEK inhibitors on Lamγ2 and p-ERK levels in control N/TERT-1 cells, cRAF1(22w) and MEK1(DD) transductants, and SCC-13 cells. Note that Lamγ2 overexpression and increased p-ERK levels in keratinocytes expressing activated mutant cRAF1 or MEK are normalized by treatment with the MEK inhibitor AZD6244, but not with the EGFR kinase inhibitor gefitinib.