Basigin

Basigin (BSG) also known as extracellular matrix metalloproteinase inducer (EMMPRIN) or cluster of differentiation 147 (CD147) is a is_associated_with::protein that in humans is encoded by the BSG is_associated_with::gene. This protein is a determinant for the Ok blood group system. Basigin has been shown to be an essential receptor on red blood cells for the human malaria parasite, Plasmodium falciparum.

Function
Basigin is a member of the is_associated_with::immunoglobulin superfamily, with a structure related to the putative primordial form of the family. As members of the immunoglobulin superfamily play fundamental roles in is_associated_with::intercellular recognition involved in various immunologic phenomena, differentiation, and development, basigin is thought also to play a role in intercellular recognition (Miyauchi et al., 1991; Kanekura et al., 1991).

It has a variety of functions. In addition to its metalloproteinase-inducing ability, basigin also regulates several distinct functions, such as is_associated_with::spermatogenesis, expression of the is_associated_with::monocarboxylate transporter and the responsiveness of is_associated_with::lymphocytes. Basigin is a type I integral membrane receptor that has many is_associated_with::ligands, including the is_associated_with::cyclophilin (CyP) proteins Cyp-A and CyP-B and certain is_associated_with::integrins. It is expressed by many cell types, including is_associated_with::epithelial cells, is_associated_with::endothelial cells and is_associated_with::leukocytes. The human basigin protein contains 269 amino acids that form two heavily glycosylated C2 type immunoglobulin-like domains at the N-terminal extracellular portion. A second form of basigin has also been characterized that contains one additional immunoglobulin-like domain in its extracellular portion.

Interactions
Basigin has been shown to interact with is_associated_with::Ubiquitin C.

Basigin has been shown to form a complex with is_associated_with::monocarboxylate transporters in the retina of mice. Basigin appears to be required for proper placement of MCTs in the membrane. In the Basigin null mouse, the failure of MCTs to integrate with the membrane may be directly linked to a failure of nutrient transfer in the retinal pigmented epithelium (the lactates transported by MCTs 1, 3, and 4 are essential nutrients for the developing RPE), resulting in loss of sight in the null animal.

Role in malaria
It has recently (November 2011) been found that basigin is a receptor that is essential to erythrocyte invasion by most strains of is_associated_with::Plasmodium falciparum, the most virulent species of the is_associated_with::plasmodium parasites that cause human is_associated_with::malaria. It is hoped that by developing antibodies to the parasite ligand for Basigin, is_associated_with::Rh5, a better vaccine for malaria might be found. Basigin is bound by the PfRh5 protein on the surface of the malaria parasite.