BPIFB2
BPI fold-containing family B, member 2, also known as bactericidal/permeability-increasing protein-like 1, is a protein that in humans is encoded by the BPIFB2 gene.
Superfamily
BPIFB2 is a member of a BPI fold protein superfamily defined by the presence of the bactericidal/permeability-increasing protein 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.Genes for the BPI/LBP/PLUNC superfamily are found in all vertebrate species, including distant homologs in non-vertebrate species such as insects, mollusks, and roundworms. Within that broad grouping is the BPIF gene family whose members encode the BPI fold structural motif and are found clustered on a single chromosome, e.g., Chromosome 20 in humans, Chromosome 2 in mouse, Chromosome 3 in rat, Chromosome 17 in pig, Chromosome 13 in cow. The BPIF gene family is split into two groupings, BPIFA and BPIFB. In humans, BIPFA consists of 3 protein encoding genes BPIFA1, BPIFA2, BPIFA3, and 1 pseudogene BPIFA4P; while BPIFB consists of 5 protein encoding genes BPIFB1, BPIFB2, BPIFB3, BPIFB4, BPIFB6 and 2 pseudogenes BPIFB5P, BPIFB9P. What appears as pseudogenes in humans may appear as fully functional genes in other species.
In humans, the BPIFB2 gene was first identified as a BPIL3 gene whose encoded protein was called LPLUNC2, but subsequently PLUNC proteins were classified as a subfamily of the BPI fold superfamily. In humans, the BPIFB2 gene is found with other members of the BPI/LBP/PLUNC superfamily in a cluster on Chromosome 20.