P75-TNFR

USA

The P75 TNFR (TNFR-II) membrane receptor is expressed on most mammalian cells. The actions of TNF-alpha are mediated via a 55, 000/60, 000 Da receptor (TNFR-I) and a 75, 000/80, 000 Da receptor (TNFR-II). The cleavage site for TNFR-II is Val192–His193, which is 14 amino acids from the cysteine-rich extracellular domain, compared with six amino acids for TNFR-I. The P75-TNFR directly mediates distinct cellular responses such as proliferation of T and B cells, activation of NF-beta, and induction of cytotoxicity. A recent study has described an assay using cells expressing TNFR-II at the cell surface to partially characterize a soluble metallosecretase that is itself secreted into the media upon phorbol ester stimulation of the cells.