A Model for the Interaction of the GM-CSF, IL-3 and IL-5 Receptors with their Ligands

Abstract

The high affinity receptors for GM-CSF, IL-3 and IL-5 are heterodimers consisting of a ligand-specific a chain and a common β chain. These proteins are members of a family of proteins known as the “cytokine receptor family” which is characterized by the presence of a 200-residue ligand-binding module. The GMCSF, IL-3 and IL-5 receptor α chains constitute a distinct subgroup and share features not found in other members of the cytokine receptor family, features which we propose to be important for their interaction with the common β chain and for their binding of the structurally-related ligands. The growth hormone receptor is a well-characterized member of the cytokine receptor family. Based on the structure of the complex between growth hormone and its receptor, we have proposed sites of contact between the GM-CSF, IL-3 and IL-5 receptors and their cognate ligands.

Key Words:

• cytokines
• leukocytes
• hemopoiesis
• homologies
• function