This entry represents a group of membrane cofactor proteins (also known as CD46 or TLX). Human CD46 acts as a cofactor for complement factor I, a serine protease which protects autologous cells against complement-mediated injury by cleaving C3b and C4b deposited on host tissue []. Rat CD46 may be involved in the fusion of the spermatozoa with the oocyte during fertilization [].
