ADP ribosyl cyclase activity of a novel bone marrow stromal cell surface molecule, BST‐1

Abstract

Human BST‐1, a bone marrow stromal cell surface molecule, is a GPI‐anchored protein that facilitates the growth of pre‐B cells. The deduced amino acid sequences of human and mouse BST‐1 show around 30% homology with those of CD38 and Aplysia ADP ribosyl cyclase. Therefore, like CD38, BST‐1 might possess ADP ribosyl cyclase activity. Here, we report the establishment of a stable transformant CHO cell line which secretes truncated human soluble BST‐1, and show that purified soluble BST‐1 displays both ADP ribosyl cyclase cADPR hydrolase activities.