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Figure 5 | Skeletal Muscle

Figure 5

From: p38β MAPK upregulates atrogin1/MAFbx by specific phosphorylation of C/EBPβ

Figure 5

C/EBPβ phosphorylation at Thr-188 is crucial for atrogin1/MAFbx upregulation by p38β or LCM. (A) C2C12 myoblasts were transfected with a plasmid encoding constitutively active p38α, p38β or empty vector. A plasmid encoding FLAG-tagged C/EBPβ mutant in which Thr-188 was replaced with alanine (LAP-T188A) or the control vector was co-transfected as indicated. After differentiation, myotubes were lysed and analyzed by western blotting for the expression of LAP-T188A (with antibodies against FLAG and C/EBPβ) and atrogin1/MAFbx. (B) C2C12 myoblasts were transfected with LAP-T188A or the empty vector as control. After differentiation, myotubes were treated with LCM or control medium for 8 h. Lysate of myotubes was analyzed by western blotting for the expression of LAP-T188A (with antibodies against FLAG and C/EBPβ) and atrogin1/MAFbx. Optical density of the bands that represent atrogin1/MAFbx was analyzed by ANOVA. *denotes a difference from control without LCM treatment and †denotes a difference from control with LCM treatment (P <0.05). LCM, Lewis lung carcinoma cell-conditioned medium.

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