Lactoferrin Recombinant Rabbit Monoclonal Antibody [JE49-60]

Function

Lactotransferrin is a major iron-binding and multifunctional protein found in exocrine fluids such as breast milk and mucosal secretions. Has antimicrobial activity, which depends on the extracellular cation concentration. Antimicrobial properties include bacteriostasis, which is related to its ability to sequester free iron and thus inhibit microbial growth, as well as direct bactericidal properties leading to the release of lipopolysaccharides from the bacterial outer membrane. Can also prevent bacterial biofilm development in P.aeruginosa infection. Has weak antifungal activity against C.albicans. Has anabolic, differentiating and anti-apoptotic effects on osteoblasts and can also inhibit osteoclastogenesis, possibly playing a role in the regulation of bone growth. Promotes binding of species C adenoviruses to epithelial cells, promoting adenovirus infection. Can inhibit papillomavirus infections. Stimulates the TLR4 signaling pathway leading to NF-kappa-B activation and subsequent pro-inflammatory cytokine production while also interfering with the lipopolysaccharide (LPS)-stimulated TLR4 signaling. Inhibits neutrophil granulocyte migration to sites of apoptosis, when secreted by apoptotic cells. Stimulates VEGFA-mediated endothelial cell migration and proliferation. Binds heparin, chondroitin sulfate and possibly other glycosaminoglycans (GAGs). Also binds specifically to pneumococcal surface protein A (pspA), the lipid A portion of bacterial lipopolysaccharide (LPS), lysozyme and DNA.

Background References

1. Kumar J et al. Crystal structure of human seminal diferric lactoferrin at 3.4 Angstrom resolution. Indian J. Biochem. Biophys. 40:14-21 (2003).

2. Day CL et al. Structure of the recombinant N-terminal lobe of human lactoferrin at 2.0 A resolution. J. Mol. Biol. 232:1084-1100 (1993).

Sequence Similarity

Belongs to the transferrin family.

Tissue Specificity

High levels are found in saliva and tears, intermediate levels in serum and plasma, and low levels in urine. In kidney, detected in the distal collecting tubules in the medulla but not in the cortical region or in blood vessels. Detected in peripheral blood neutrophils (at protein level). Isoform 1 and isoform DeltaLf are expressed in breast, prostate, spleen, pancreas, kidney, small intestine, lung, skeletal muscle, uterus, thymus and fetal liver. Isoform 1 is expressed in brain, testis and peripheral blood leukocytes; isoform DeltaLf is barely detectable in these tissues. Isoform DeltaLf is expressed in placenta, liver and ovary; isoform 1 is barely detectable in these tissues. In kidney, isoform 1 is expressed at high levels in the collecting tubules of the medulla but at very low levels in the cortex.

Post-translational Modification

[Isoform DeltaLf]: Phosphorylation at Ser-10 activates the transcriptional activity. Phosphorylation at Ser-10 also promotes proteasomal degradation. Alternatively can undergo O-GlcNAcylation at Ser-10.; [Isoform DeltaLf]: O-GlcNAcylation at Ser-10 inhibits DNA binding and negatively regulates the transcriptional activity. Alternatively can undergo phosphorylation at Ser-10.; Poly-N-acetyllactosaminic carbohydrate moiety seems to be needed for TLR4 activation.

Subcellular Location

Cytoplasm. Nucleus. Secreted.

UNIPROT

SwissProt: P02788 Human

Synonyms