Bactericidal/permeability-increasing protein (BPI) is a potent antimicrobial protein that binds to and neutralises lipopolysaccharide (LPS), a glycolipid present in the outer membrane of Gram-negative bacteria [].In mammals, two related LPS-binding proteins mediate the biological effects of LPS: LPS-binding protein (LBP) and BPI. LBP is a plasma protein that enhances the inflammatory response to LPS, whereas BPI is found in lysosomal granules of polymorphonuclear neutrophils, is bactericidal, and neutralises the toxic effects of LPS []. BPI belongs to the lipid transfer/lipopolysaccharide binding protein (LT/LBP) family, with LBP, the cholesteryl ester transfer protein (CETP) and the phospholipid transfer protein (PLTP) [].This entry represents mammalian BPI.
BPI fold-containing family C protein, also known as bactericidal/permeability-increasing protein-like 2 (BPIL2), is a lipid transfer/lipopolysaccharide binding protein that seems to share an evolutionary origin with BPIL1 and BPIL3. BPIL2 shows prominent expression in psoriasis patients skin [].
BPI fold-containing family B member 6, also known as bactericidal/permeability-increasing protein-like 3 (BPIL3), belongs to the PLUNC family, whose members are involved in host defence against bacteria [, , ]. BPIL3 is highly expressed in hypertrophic tonsils [].
BPI fold-containing family B member 3 (BPIFB3), also known as long palate, lung and nasal epithelium carcinoma-associated protein 3 (LPLUNC3), is a member of the BPI/LBP/PLUNC family [, ]. BPIFB3 regulates autophagy and coxsackievirus B replication through a noncanonical pathway [].
BPI fold-containing family A member 3, also known as short palate, lung and nasal epithelium carcinoma-associated protein 3 (Splunc3) belongs to the PLUNC family, whose members are involved in host defence against bacteria []. The function of Splunc3 is not known.
This entry represents long palate, lung and nasal epithelium carcinoma-associated protein 1 (Lplunc1), also known as BPI fold-containing family B member 1, which belongs to the palate, lung, and nasal epithelium clone (PLUNC) family. It is a small secreted protein expressed in the oropharynx and upper airways of humans, mice, rats, and cows []. It may play a role in innate immunity in the mouth, nose and lungs and in the formation of the left-right axis in the node of the developing embryo [, ].
Bactericidal/permeability-increasing protein fold-containing family member A1 (BPIFA1), formerly known as SPLUNC1, participates in host protection through its antimicrobial, surfactant, and immunomodulatory properties [, ]. Its expression is largely restricted to the respiratory tract [].
This entry represents the bactericidal permeability-increasing protein (BPI) and the lipopolysaccharide-binding protein (LBP). The crystal structures of BPI and LBP are similar [], and they may represent a common gene family of lipid-binding proteins [].In mammals, LBP and BPI mediate the biological effects of LPS (lipopolysaccharide), a glycolipid present in the outer membrane of Gram-negative bacteria. LBP is a plasma protein that enhances the inflammatory response to LPS, whereas BPI is found in lysosomal granules of polymorphonuclear neutrophils, is bactericidal, and neutralises the toxic effects of LPS [, ]. LBP is an acute phase serum protein secreted mainly by the liver that modulates the LPS-induced immune response. LBP binds mainly to the lipid A moiety of LPS and acts as an affinity enhancer for CD14, facilitating its association with LPS [].
The BPI (bactericidal permeability-increasing proteins)/LBP (lipopolysaccharide-binding proteins)/PLUNC (palate, lung and nasal epithelium clone) family consists of proteins involved in host defence against bacteria, many acting in early recognition of bacteria in the upper respiratory tract [, , ]. They share homology with cholesterol ester transfer protein (CETP) and phospholipid transfer protein (PLTP), both of which are involved in lipid transport in blood plasma []. This entry also matches UPF0522 proteins from Dictyostelium (slime mold), whose function is unknown.
This superfamily represents a structural domain with a core structure consisting of two layers, alpha/beta. These homologous structural domains can show little sequence identity with each other. A number of mammalian lipid-binding serum glycoproteins contain one or more such structural domains, including:Bactericidal permeability-increasing protein (BPI)Lipopolysaccharide-binding protein (LBP)Cholesteryl ester transfer protein (CETP)Phospholipid transfer protein (PLTP)Palate, lung and nasal epithelium carcinoma-associated protein (PLUNC)Bactericidal permeability-increasing protein (BPI) is a potent antimicrobial protein of 456 residues that binds to and neutralises lipopolysaccharides from the outer membrane of Gram-negative bacteria []. BPI contains two domains that adopt the same structural fold, even though they have little sequence similarity []. Lipopolysaccharide-binding protein (LBP) is an endotoxin-binding protein that is closely related to, and functions in a co-ordinated manner with BPI to facilitate an integrated host response to invading Gram-negative bacteria [].Cholesteryl ester transfer protein (CETP) is a glycoprotein that facilitates the transfer of lipids (cholesteryl esters and triglycerides) between the different lipoproteins that transport them through plasma, including HDL, LDL, VLDL and chylomicrons. These lipoproteins shield the lipids from water by encapsulating them within a coating of polar lipids and proteins [].Phospholipid transfer protein (PLTP) exchanges phospholipids between lipoproteins and remodels high-density lipoproteins (HDLs) [].Palate, lung and nasal epithelium carcinoma-associated protein (PLUNC) is a potential host defensive protein that is secreted from the submucosal gland to the saliva and nasal lavage fluid. PLUNC appears to be a secreted product of neutrophil granules that participates in an aspect of the inflammatory response that contributes to host defence []. Short palate, lung and nasal epithelium clone 1 (SPLUNC1) may bind the lipopolysaccharide of Gram-negative nanobacteria, thereby playing an important role in the host defence of nasopharyngeal epithelium [].
This entry represents the N-terminal domain found in several lipid-binding serum glycoproteins. The N- and C-terminal domains share a similar two-layer alpha/beta structure, but they show little sequence identity. Proteins containing this N-terminal domain include:Bactericidal permeability-increasing protein (BPI)Lipopolysaccharide-binding protein (LBP)Cholesteryl ester transfer protein (CETP)Phospholipid transfer protein (PLTP)Palate, lung and nasal epithelium carcinoma-associated protein (PLUNC)Bactericidal permeability-increasing protein (BPI) is a potent antimicrobial protein of 456 residues that binds to and neutralises lipopolysaccharides from the outer membrane of Gram-negative bacteria []. BPI contains two domains that adopt the same structural fold, even though they have little sequence similarity []. Lipopolysaccharide-binding protein (LBP) is an endotoxin-binding protein that is closely related to, and functions in a co-ordinated manner with BPI to facilitate an integrated host response to invading Gram-negative bacteria [].Cholesteryl ester transfer protein (CETP) is a glycoprotein that facilitates the transfer of lipids (cholesteryl esters and triglycerides) between the different lipoproteins that transport them through plasma, including HDL, LDL, VLDL and chylomicrons. These lipoproteins shield the lipids from water by encapsulating them within a coating of polar lipids and proteins [].Phospholipid transfer protein (PLTP) exchanges phospholipids between lipoproteins and remodels high-density lipoproteins (HDLs) [].Palate, lung and nasal epithelium carcinoma-associated protein (PLUNC) is a potential host defensive protein that is secreted from the submucosal gland to the saliva and nasal lavage fluid. PLUNC appears to be a secreted product of neutrophil granules that participates in an aspect of the inflammatory response that contributes to host defence []. Short palate, lung and nasal epithelium clone 1 (SPLUNC1) may bind the lipopolysaccharide of Gram-negative nanobacteria, thereby playing an important role in the host defence of nasopharyngeal epithelium [].
This entry represents the C-terminal domain found in several lipid-binding serum glycoproteins. The N- and C-terminal domains share a similar two-layer alpha/beta structure, but they show little sequence identity. Proteins containing this C-terminal domain include:Bactericidal permeability-increasing protein (BPI)Lipopolysaccharide-binding protein (LBP)Cholesteryl ester transfer protein (CETP)Phospholipid transfer protein (PLTP)Palate, lung and nasal epithelium carcinoma-associated protein (PLUNC)Bactericidal permeability-increasing protein (BPI) is a potent antimicrobial protein of 456 residues that binds to and neutralises lipopolysaccharides from the outer membrane of Gram-negative bacteria []. BPI contains two domains that adopt the same structural fold, even though they have little sequence similarity []. Lipopolysaccharide-binding protein (LBP) is an endotoxin-binding protein that is closely related to, and functions in a co-ordinated manner with BPI to facilitate an integrated host response to invading Gram-negative bacteria [].Cholesteryl ester transfer protein (CETP) is a glycoprotein that facilitates the transfer of lipids (cholesteryl esters and triglycerides) between the different lipoproteins that transport them through plasma, including HDL, LDL, VLDL and chylomicrons. These lipoproteins shield the lipids from water by encapsulating them within a coating of polar lipids and proteins [].Phospholipid transfer protein (PLTP) exchanges phospholipids between lipoproteins and remodels high-density lipoproteins (HDLs) [].Palate, lung and nasal epithelium carcinoma-associated protein (PLUNC) is a potential host defensive protein that is secreted from the submucosal gland to the saliva and nasal lavage fluid. PLUNC aapears to be a secreted product of neutrophil granules that participates in an aspect of the inflammatory response that contributes to host defence []. Short palate, lung and nasal epithelium clone 1 (SPLUNC1) may bind the lipopolysaccharide of Gram-negative nanobacteria, thereby playing an important role in the host defence of nasopharyngeal epithelium [].
This entry represents a conserved sequence region found in the N-terminal domain of several lipid-binding serum glycoproteins. The N- and C-terminal domains of these proteins share a similar two-layer alpha/beta structure, but they show little sequence identity. Proteins containing this N-terminal domain include:Bactericidal permeability-increasing protein (BPI)Lipopolysaccharide-binding protein (LBP)Cholesteryl ester transfer protein (CETP)Phospholipid transfer protein (PLTP)Palate, lung and nasal epithelium carcinoma-associated protein (PLUNC)Bactericidal permeability-increasing protein (BPI) is a potent antimicrobial protein of 456 residues that binds to and neutralises lipopolysaccharides from the outer membrane of Gram-negative bacteria []. BPI contains two domains that adopt the same structural fold, even though they have little sequence similarity []. Lipopolysaccharide-binding protein (LBP) is an endotoxin-binding protein that is closely related to BPI, and functions with it to facilitate an integrated host response to invading Gram-negative bacteria [].Cholesteryl ester transfer protein (CETP) is a glycoprotein that facilitates the transfer of lipids (cholesteryl esters and triglycerides) between the different lipoproteins that transport them through plasma, including HDL, LDL, VLDL and chylomicrons. These lipoproteins shield the lipids from water by encapsulating them within a coating of polar lipids and proteins [].Phospholipid transfer protein (PLTP) exchanges phospholipids between lipoproteins and remodels high-density lipoproteins (HDLs) [].Palate, lung and nasal epithelium carcinoma-associated protein (PLUNC) is a potential host defensive protein that is secreted from the submucosal gland to the saliva and nasal lavage fluid. PLUNC aapears to be a secreted product of neutrophil granules that participates in an aspect of the inflammatory response that contributes to host defence []. Short palate, lung and nasal epithelium clone 1 (SPLUNC1) may bind the lipopolysaccharide of Gram-negative nanobacteria, thereby playing an important role in the host defence of nasopharyngeal epithelium [].
