Pancreatic islet cells express BST-1, a CD38-like surface molecule having ADP-ribosyl cyclase activity.
Kajimoto Y,
Miyagawa J,
Ishihara K,
Okuyama Y,
Fujitani Y,
Itoh M,
Yoshida H,
Kaisho T,
Matsuoka T,
Watada H,
Hanafusa T,
Yamasaki Y,
Kamada T,
Matsuzawa Y,
Hirano T.
First Department of Medicine, Osaka University School of Medicine, Japan.
Cyclic ADP-ribose (cADPR), a well-known stimulator of ca(2+) release from the intracellular Ca(2+) pool, has recently emerged as a potential regulator of insulin secretion in pancreatic beta cells. As recently described, BST-1 is a glycosyl-phosphatidylinositol (GPI)-anchored surface molecule that exhibits homology with CD38 and Aplysia ADP-ribosyl cyclase. Like CD38, BST-1 has both ADP-ribosyl cyclase and cADPR hydrolase activities. As a step toward elucidating the physiological role of cADPR in insulin secretion we examined whether BST-1 is expressed in pancreatic islet cells. Sensitive reverse transcription-polymerase chain reaction detected almost as abundant expression of BST-1 mRNA in pancreatic islets as CD38 mRNA. Immunohistochemical analyses utilizing mirror image sections revealed that BST-1 protein is expressed in a majority of the cells in pancreatic islets and that at least beta cells and, to an even greater extent, alpha cells express BST-1. These observations suggest the involvement of multiple enzymes in the regulation of cADPR concentrations in pancreatic islet cells.
PMID: 8645283 [PubMed - indexed for MEDLINE]