P4HB Protein, Human (HEK293, His)

The P4HB protein, a multifunctional entity, catalyzes the intricate processes of forming, breaking, and rearranging disulfide bonds. Positioned at the cell surface, it acts as a reductase, cleaving disulfide bonds of proteins linked to the cell and potentially causing structural modifications of exofacial proteins. Intracellularly, P4HB is involved in forming and rearranging disulfide bonds of nascent proteins. At elevated concentrations, and under the phosphorylation influence of FAM20C, it functions as a chaperone, preventing the aggregation of misfolded proteins. Conversely, at lower concentrations, it exhibits anti-chaperone activity by facilitating aggregation. P4HB's versatility extends to its participation as a structural subunit in various enzymes such as prolyl 4-hydroxylase and microsomal triacylglycerol transfer protein MTTP. Furthermore, it serves as a receptor for LGALS9, with this interaction influencing disulfide reductase activity at the cell surface of Th2 T helper cells, altering the plasma membrane's redox state, and enhancing cell migration. This diverse range of functions underscores the pivotal role of P4HB in cellular processes, including protein folding, redox regulation, and cell migration.