E. Vincan et al., ISOLATION OF NEONATAL CARDIOMYOCYTES REDUCES THE EXPRESSION OF THE GTP-BINDING PROTEIN, G(H), Journal of Molecular and Cellular Cardiology, 27(10), 1995, pp. 2393-2396
alpha(1)-Adrenoceptors in most tissues couple with the heterotrimeric
GTP-binding protein G(q), the alpha subunit of which activates the bet
a-isoforms of phospholipase C. However, in heart (and in liver) alpha(
1)-adrenoceptors have been reported to couple to a high molecular weig
ht GTP-binding protein, G(h), which functions both as a type II transg
lutaminase and as a receptor coupling protein. G(h) activates a phosph
olipase isoform distinct from phospholipase C-beta. Here we report tha
t isolation and culture of neonatal cardiomyocytes decreased the expre
ssion of G(h) without reducing the content of G(q) or G(l), G(h) was r
eadily detected in extracts from intact neonatal and adult heart tissu
es. The expression of G(h) thus appears to be a feature of intact card
iac tissue. (C) 1995 Academic Press Limited