Figure 6.

Phosphorylation of Txnip Thr³⁴⁹ regulates cytokine-induced ubiquitination. A, A549 cells were infected with lentivirus expressing either Txnip_WT or Txnip_349V, treated with the proteasome inhibitor MG132 (10 μm), and stimulated with TNFα (10 ng/ml, 60 min) ± ERK1/2 MAP kinase inhibitor (EI) (U0126, 10 μm). Ubiquitinated proteins were isolated from cell lysates by IP, and Txnip immunoblots were prepared from IP eluates. B, densitometric analysis of ubiquitinated Txnip blots shown in A. The results are relative to MG132-only control (CTL; n = 3 per condition, one-sample t test). **, p < 0.01; *, p < 0.05.