Lack of critical domains in the beta-chain of hepatocyte growth factor.

Hepatocyte growth factor (HGF) is a cytokine with pleiotropic effects on many different cell types. Its biological activities depend on the disulfide-linked alpha beta heterodimeric molecule. To study the functions of the beta-chain of HGF, insect cell-expressed HGFs prepared from nested deletions from C-terminus of beta-chain were studied for their biological activities and ligand-binding functions. The results demonstrated that the functions of HGF are dependent on the intactness of its beta-chain. The loss of HGF activities is correlated with the progressive deletion of beta-chain. There is not a single critical domain in the beta-chain that is essential for the functions of HGF. We propose that beta-chain may act to stabilize the ligand-receptor binding or contribute to the proper conformation of HGF to interact with its receptor.