Mouse Protein Disulfide-isomerase, P4HB ELI

This multifunctional protein catalyzes the formation, breakage and rearrangement of disulfide bonds.

At the cell surface, seems to act as a reductase that cleaves disulfide bonds of proteins attached to the cell.

May therefore cause structural modifications of exofacial proteins.

Inside the cell, seems to form/rearrange disulfide bonds of nascent proteins.

At high concentrations, functions as a chaperone that inhibits aggregation of misfolded proteins.

At low concentrations, facilitates aggregation (anti-chaperone activity).

May be involved with other chaperones in the structural modification of the TG precursor in hormone biogenesis.

Also acts a structural subunit of various enzymes such as prolyl 4-hydroxylase and microsomal triacylglycerol transfer protein MTTP (By similarity). Receptor for LGALS9; the interaction retains P4HB at the cell surface of Th2 T helper cells, increasing disulfide reductase activity at the plasma membrane, altering the plasma membrane redox state and enhancing cell migration (PubMed:21670307).