Figure 2.

A possible mechanism responsible for the oncogenic role of SULF1. TGF-β1, bound to the sulfate moiety from 6-O of heparan sulfate on HSPGs, is released following the desulfation of 6-O of heparan sulfate on HSPGs by SULF1. This allows TGF-β1 binding to the receptor system. After binding and phosphorylation, the receptor activates by phosphorylation the SMAD2 and SMAD3 effectors. This is followed by the formation of heteromeric complexes of SMAD2 and SMAD3 with SMAD4, which then translocate to the nucleus and activate specific DNA sequences involved in EMT.