The Strategies of Organization of the Fish Plasma Proteome: with and without Albumin

Abstract

Various principles of organization of the blood plasma proteome are considered using the example of teleost fishes, whose lower members have albumin, while the higher members have lost it. Albumin, which creates the colloid osmotic pressure of blood plasma and is involved in lipid transport and other functions, is compared to the multifunctional potential of high-density lipoproteins (HDL), which dominate in the blood of bony fishes and probably compensate for the lack of albumin in higher Teleostei. The elements of the structural organization and functions of two proteins, that is, albumin and apolipoprotein A (as a part of HDL) that are dominant in the blood of fish, the features of the plasma proteome in marine and freshwater fishes, and the hypothesis of the evolution of the plasma proteome and a special strategy of osmoregulation in Teleostei (with the involvement of serum HDL and without albumin) are considered. Two strategies of organization of the fish blood plasma proteome are noted: on the branch that led to Teleostei an expansion of the size–compositional range of lipoproteins and an increase in the role of HDL in metabolic processes occurred; on the branch that led to Mammalia a separation of the lipid transport and osmoregulation functions occurred between lipid and albumin and an increase in the albumin content in the blood plasma.