Thus, redox-regulation of PTP1B may also have two different functions in the development of insulin resistance: i) by dephosphorylating the β-subunit of the IR and AKT, therefore resulting in direct inhibition of the insulin signalling cascade, and ii) by indirectly activating the lipogenic transcription factor SREBP-1c, followed by steatosis and lipotoxicity. This evidence concerns the gene SREBF1 and Insulin resistance.