Specific inhibition of HDAC2 enhances insulin signalling. MCF-7 cells were transfected with short inhibitory RNA oligonucleotides (80 and 160 pmol as indicated) for four hours and cultured a further 48 hours prior to treatment with PMA (10 ng/ml for 4 hours) and stimulation with insulin (100 nM) for 10 minutes. IRS-1 was immunoprecipitated and western blotted for the presence of HDAC2, phosphotyrosine, acetyl lysine and IRS-1 itself. The graphs show average data (± SEM) for 3–5 independent experiments, normalised to the insulin response alone. P-Y: phosphotyrosine.