BPIFB4

BPI fold containing family B, member 4 (BPIFB4) is a protein that in humans is encoded by the BPIFB4 gene. It was formerly known as "Long palate, lung and nasal epithelium carcinoma-associated protein 4" encoded by the LPLUNC4 gene. The BPIFB4 gene sequence predicts 4 transcripts (splice variants); 3 isoforms have been well characterized. In a variety of mammals, BPIFB4 is generally expressed in very high levels in the olfactory epithelium (nasal mucosa), high levels in the gonads (testis, ovary) and pituitary, moderate levels in white blood cells (monocytes) It can occur either localized in the cytoplasm of cells or secreted and circulated systemically in blood plasma.

== Superfamily == BPIFB4 is a member of a BPI fold protein superfamily defined by the presence of the bactericidal/permeability-increasing protein fold (BPI fold) which is formed by two similar domains in a "boomerang" shape. This superfamily is also known as the BPI/LBP/PLUNC family or the BPI/LPB/CETP family. The BPI fold creates apolar binding pockets that can interact with hydrophobic and amphipathic molecules, such as the acyl carbon chains of lipopolysaccharide found on Gram-negative bacteria, but members of this family may have many other functions. thumb|left|BPIFB4 is a member of the BPI-fold gene family and the BPI/LBP/PLUNC protein superfamily