In the soluble state, catalyzes glutaredoxin-like thiol disulfide exchange reactions with reduced glutathione as electron donor (PubMed:28198360, PubMed:37759794). Reduced in a glutathione-dependent way and secreted into the extracellular matrix where it activates TGM2 and promotes blood vessel growth during tissue remodeling as occurs in tumorigenesis. Can reduce specific cysteines in TGM2 and regulate cofactor binding (PubMed:28198360). Can insert into membranes and form outwardly rectifying chloride ion channels. May participate in cellular growth control. {ECO:0000269|PubMed:28198360, ECO:0000269|PubMed:32066374, ECO:0000269|PubMed:37759794, ECO:0000269|PubMed:9880541}. This is the function of CLIC3 (CLIC family member 3, Ensembl gene identifier ENSG00000169583).