SMAD2 and systemic sclerosis: As described above TGF-β can induce STAT1 activation in the HaCaT (Fig. 4A-B) and SSc fibroblast media is able to activate SMAD2/3 in the HaCaT (Fig. 4D, H) and the activation of both is attenuated when CLIC4 is inhibited in the HaCaT.