Figure 8.

Blocking nBP1a binding to PKM2 by small peptides inhibits gene expression. A, co-IP analysis of overexpressed FLAG–PKM2 binding to HA-nBP1a in HepG2 cells in the presence of peptides P2–P8 (8 μm) or without peptide (CT, peptide solvent control; None, no-treatment control). The lower panel shows the peptide sequences corresponding to aa 1–60 of SREBP-1a. B, effects of 8 μm peptide P8 on overexpressed HA-nBP1a protein levels in HepG2 cells. C, effects of peptides P2–P9 (8 μm) on the Fasn promoter activity in HepG2 cells as detected by luciferase reporter assay. D, effects of treatment with peptides P2–P9 (8 μm) for 24 h on the mRNA levels of indicated genes in HepG2 cells. E, effects of P8 or control peptide CP (8 μm) on the Fasn promoter activity upon overexpressing WT or T59A mutant SREBP-1a in HepG2 cells as detected by luciferase reporter assay. F, suggested model shows how the small peptide P8 may work.