Expression of nucleotide pyrophosphatase and alkaline phosphodiesterase I activities of PC-1, the murine plasma cell antigen.
Nucleotide pyrophosphatase (EC 3.6.1.9) is a membrane enzyme purified from a number of mammalian sources that may have alkaline phosphodiesterase I (EC 3.1.4.1) activity as well. The mol. wt and subunit structure of this membrane glycoprotein are similar to that of the murine plasma cell alloantigen, PC-1. The PC-1 protein is a disulfide-bonded dimer of identical 115 kDa polypeptides that is selectively expressed on B lineage cells that have reached the degree of maturation associated with immunoglobulin secretion. It also has restricted expression in certain non-lymphoid tissues. In this report, we show that alkaline phosphodiesterase I activity parallels PC-1 mRNA expression in a number of B lineage cell lines at different stages of differentiation. Furthermore, we demonstrate increases in both nucleotide pyrophosphatase and alkaline phosphodiesterase I enzymatic activities in transiently transfected COS-7 cells expressing a cloned PC-1 cDNA construction. These results extend our previous immunological and correlative studies and directly ascribe an enzymatic activity to this cell surface differentiation antigen. These experiments also demonstrate that a single protein is responsible for both alkaline phosphodiesterase I and nucleotide pyrophosphatase activities.
Rebbe
N F
NF
Washington University Medical Service, Veterans Affairs Medical Center, John Cochran Division, St Louis, MO 63106.
Tong
B D
BD
Hickman
S
S
D000818:Animals; D000944:Antigens, Differentiation, B-Lymphocyte / Q000096:biosynthesis*; D015152:Blotting, Northern; D015153:Blotting, Western; D002460:Cell Line; D015870:Gene Expression; D016393:Lymphoma, B-Cell / Q000378:metabolism; D051379:Mice; D043264:Phosphodiesterase I; D010727:Phosphoric Diester Hydrolases / Q000096:biosynthesis*; D010950:Plasma Cells / Q000276:immunology*; D010954:Plasmacytoma / Q000378:metabolism; D010957:Plasmids; D011755:Pyrophosphatases / Q000096:biosynthesis*; D012313:RNA / Q000032:analysis; D012333:RNA, Messenger / Q000096:biosynthesis; D014162:Transfection
D000944:Antigens, Differentiation, B-Lymphocyte; D012333:RNA, Messenger; D012313:RNA; D010727:Phosphoric Diester Hydrolases; D043264:Phosphodiesterase I; D011755:Pyrophosphatases; C021899:nucleotide pyrophosphatase