Non-classical protein release independent of the ER-Golgi pathway has been reported for an increasing number of proteins lacking an N-terminal signal sequence. The export of FGF1 and IL-1α, two pro-angiogenic polypeptides, provides two such examples. In both cases, export is based on the Cu²⁺-dependent formation of multiprotein complexes containing the S100A13 protein and might involve translocation of the protein across the membrane as a `molten globule'. FGF1 and IL-1α are involved in pathological processes such as restenosis and tumor formation. Inhibition of their export by Cu²⁺ chelators is thus an effective strategy for treatment of several diseases.