bactericidal permeability-increasing protein; BPI; CAP 57 (BPI)

Function

• cytotoxic action of BPI is limited to many species of Gram-negative bacteria specificity may be explained by a strong affinity of the very basic N-terminal half for the negatively charged lipopolysaccharides that are unique to the Gram-negative bacterial outer envelope
• has antibacterial activity against the P. aeruginosa, this activity is inhibited by LPS from P. aeruginosa
• during phagocytosis & degranulation, proteases may be released & activated & cleave BPI at the junction of the N- & C-terminal portions of the molecule, providing controlled release of the N-terminal antibacterial fragment when bacteria are ingested

Structure

• monomer. homodimer; disulfide-linked
• the N-terminal region may be exposed to the interior of the granule, whereas the C-terminal portion may be embedded in the membrane
• belongs to the BPI/LBP/plunc superfamily, BPI/LBP family
• contains 2 LRR repeats (leucine-rich repeats)

Compartment

• secreted
• cytoplasmic granule membrane
• membrane-associated in polymorphonuclear leukocyte (PMN) granules

Expression

restricted to cells of the myeloid series

More general terms

• secreted protein
• membrane protein
• leucine-rich repeat-containing protein (LRRC)
• glycoprotein

Additional terms

• bactericidal/permeability-increasing protein-like

Database

• UniProt: http://www.uniprot.org/uniprot/P17213.html
• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=671
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:671
• OMIM: https://mirror.omim.org/entry/109195