Y. Kajimoto et al., PANCREATIC-ISLET CELLS EXPRESS BST-1, A CD38-LIKE SURFACE-MOLECULE HAVING ADP-RIBOSYL CYCLASE ACTIVITY, Biochemical and biophysical research communications, 219(3), 1996, pp. 941-946
Cyclic ADP-ribose (cADPR), a well-known stimulator of Ca2+ release fro
m the intracellular Ca2+ pool, has recently emerged as a potential reg
ulator of insulin secretion in pancreatic beta cells. As recently desc
ribed, BST-1 is a glycosyl-phosphatidylinositol (GPI)-anchored surface
molecule that exhibits homology with CD38 and Aplysia ADP-ribosyl cyc
lase. Like CD38, BST-1 has both ADP-ribosyl cyclase and cADPR hydrolas
e activities. As a step toward elucidating the physiological role of c
ADPR in insulin secretion, we examined whether BST-I is expressed in p
ancreatic islet cells. Sensitive reverse transcription-polymerase chai
n reaction detected almost as abundant expression of BST-1 mRNA. in pa
ncreatic islets as CD38 mRNA. Immunohistochemical analyses utilizing m
inor image sections revealed that BST-1 protein is expressed in a majo
rity of the cells in pancreatic islets and that at least beta cells an
d, to an even greater extent, alpha cells express BST-1. These observa
tions suggest the involvement of multiple enzymes in the regulation of
cADPR concentrations in pancreatic islet cells. (C) 1996 Academic Pre
ss, Inc.