Rhodnius prolixus amine-binding protein and similar proteins
Rhodnius prolixus amine-binding protein (ABP) plays an important role in biogenic amine binding; it binds serotonin and norepinephrine with high affinity. It is a subgroup of the lipocalin NP-like family. Nitrophorins (NPs) represent a group of nitric oxide (NO)-carrying heme proteins found in the saliva of Rhodnius prolixus. The lipocalin NP-like family belongs to the lipocalin/cytosolic fatty-acid binding protein family which has a large beta-barrel ligand-binding cavity. Lipocalins are mainly low molecular weight extracellular proteins that bind principally small hydrophobic ligands, and form covalent or non-covalent complexes with soluble macromolecules, as well as membrane bound-receptors. They participate in processes such as ligand transport, modulation of cell growth and metabolism, regulation of immune response, smell reception, tissue development and animal behavior. Cytosolic fatty-acid binding proteins, also bind hydrophobic ligands in a non-covalent, reversible manner, and have been implicated in intracellular uptake, transport and storage of hydrophobic ligands, regulation of lipid metabolism and sequestration of excess toxic fatty acids, as well as in signaling, gene expression, inflammation, cell growth and proliferation, and cancer development.
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