The sugared path to a normal lung: soluble beta-galactoside-specific lectins.

The diverse functions of a family of soluble beta-galactoside-binding proteins in lung are discussed. The smallest and most abundant member, a 14-kDa lectin, appears to be a negative modulator of cell growth. Larger members of this family include RL29, a protein involved in the regulation of cytoplasmic RNA levels, and one subunit of the cell surface elastin receptor involved in the regulation of elastic fibrillogenesis. The structure and function of other members of this family remain to be elucidated, but probably homologous carboxy-terminal domains will specify the galactose-binding function and varied amino-terminal domains will specify the diverse biological functions. Although currently these functions are being described at the cellular level, these beta-galactoside-binding proteins appear to have important roles in regulating lung physiology.