The lipoproteins are the mediators of lipid transport carrying out the transport of polar lipids in the polar environment of physiological fluids, a role important irrespective of the systematic position of the organisms.
Lipoproteins have been found in species from different phyla but they are best studied in vertebrates and insects..
We are interested in the lipoproteins of the invertebrates
Lipoproteins not only carry out lipid transport but also have other functions. In crayfish, they have defensive functions being able to bind bacterial carbohydrates by a beta-glucan binding site
According to their density lipoproteins are classified into four groups: the very low-density (VLDL), low-density (LDL), high-density (HDL) and the very high-density (VHDL) lipoprotein. In crustaceans, two classes of sex independent lipoproteins are present: the ß-glycan-binding-proteins/HDL's, which possesses defensive functions besides its lipid transport function, and the clotting proteins/VHDL. These two lipoproteins are globular in shape with a diameter of ~7 nm and have a lipid content below 20%.
Recent molecular analysis () has shown, that the lipoproteins of crustacea (i.e. the decapods) show a closer relationsship to the lipoprotein family of the vitellogenins of other phyla such as insects and vetebrates, lipoproteins that serve for the supply of storage proteins and lipids in the the growing oocyte. In contrast, the