Skip to main content
. 2002 May;22(10):3389–3403. doi: 10.1128/MCB.22.10.3389-3403.2002

FIG. 9.

FIG. 9.

MKK3/6 mediates the activation of p38 by oncogenic ras and active MEK1. (A) Ha-RasV12 and MEK1Q56P induced the accumulation of active MKK3/6 but had no effect on the levels of active MKK4. The levels of phospho-MKK3/6 (P-MKK3/6), actin, phospho-MKK4 (P-MKK4), and MKK4 were determined by Western blotting 10 days after the transduction of BJ cells at PD 33 with a vector control (BP), oncogenic Ras (HaRasV12), or constitutively active MEK1 (MEK1Q56P). The levels of phospho-MKK4 (P-MKK4) and MKK4 were also determined in BJ cells (PD 26) treated with 700 mM NaCl for 15 min (NaCl) or left untreated (−). (B) Up-regulation of phospho-MKK3/6 by Ha-RasV12 and MEK1Q56P relied on MEK activity. The levels of phospho-MKK3/6 (P-MKK3/6) and actin were determined by Western blotting 7 days after the transduction of BJ cells at PD 39 with a vector control (BP), Ha-RasV12 (Ras), or MEK1Q56P (MEK1) in the presence of vehicle control (Con) or U0126 (U). (C) MKK3 is required for p38 activation by oncogenic ras and active MEK1. The levels of phospho-p38 (P-p38) and MKK3 were determined by Western blot analysis in BJ cells expressing a dominant-negative allele of MKK3 (MKK3A) or a vector control (BH) 8 days after transduction at PD 33 with Ha-RasV12 (Ras), MEK1Q56P (MEK1), or a vector control.