Symposium on cytoplasmic transport of small molecules-Overview

Abstract

Soluble cytoplasmic binding proteins have been associated with a wide range of metabolites, including inorganic and organic anions, lipids and numerous xenobiotics. They occur in most tissues of the body. The function of these molecules has been debated since their discovery. Newer experimental methods have permitted direct demonstration of their role in catalyzing the intracellular transport of small molecules. They accomplish this by increasing the concentration of the diffusing species in the aqueous cytosolic phase. Thus, they are most important for molecules that would otherwise have very low concentrations in the cytosol. Certain binding proteins also interact directly with membranes to catalyze transfer of their ligands and possibly to target them to intracellular sites. This symposium summarizes current data and thinking on the mechanisms of cytoplasmic transport, with emphasis on the role of soluble carrier proteins in the overall uptake and metabolism of small molecules.