L. Franco et al., SELF-AGGREGATION OF THE TRANSMEMBRANE GLYCOPROTEIN CD38 PURIFIED FROMHUMAN ERYTHROCYTES, Biochemical and biophysical research communications, 202(3), 1994, pp. 1710-1715
The 46 kDa human transmembrane glycoprotein CD38 is a multicatalytic e
nzyme exhibiting ADPribosyl cyclase, cyclic ADPribose hydrolase and NA
D(+)-glycohydrolase activities at its extracellular domain. When CD38,
purified to homogeneity from human erythrocyte membranes, was incubat
ed with NAD(+) or beta-mercaptoethanol, extensive aggregation took pla
ce. Addition of both compounds to CD38 led to the formation of still l
arger aggregates (over 300 nm), which were resistant to TCA precipitat
ion. Extensive and stable CD38 self-aggregation was shown by, i) SDS-P
AGE and autoradiography of the [P-32]NAD(+)-incubated CD38, ii) SDS-PA
GE followed by immunochemical detection of CD38 on the transblots, iii
) direct electron microscopy on negatively stained CD38 samples. Self-
aggregation of CD38 might be correlated with its putative function as
a transducer of activation and proliferation signals in a number of he
matopoietic cells. (C) 1994 Academic Press, Inc.