M. Horiuchi et al., Stimulation of different subtypes of angiotensin II receptors, AT(1) and AT(2) receptors, regulates STAT activation by negative crosstalk, CIRCUL RES, 84(8), 1999, pp. 876-882
Angiotensin II type 2 (AT(2)) receptor exerts an inhibitory action on cell
growth. In the present study, we report that the Stimulation of AT(2) recep
tor in AT(2) receptor cDNA-transfected mt-adult vascular smooth muscle cell
s (VSMCs) inhibited angiotensin II type 1 (AT(2)) receptor-mediated tyrosin
e phosphorylation of STAT (signal transducers and activators of transcripti
on) 1 alpha/beta, STAT2, and STAT3 without influence on Janus kinase. AT(2)
receptor activation also inhibited the tyrosine phosphorylation of STAT1 a
lpha/beta induced by interferon-gamma, epidermal growth factor, and platele
t-derived growth factor. Similar effects of AT(2) receptor were observed in
R3T3 fibroblast and mouse fetal VSMCs, which express endogenous AT(2) rece
ptor. Moreover, AT(2) receptor inhibited serine:phosphorylation of STAT1 al
pha and STAT3 via the inhibition of extracellular signal-regulated kinase (
ERK) activation.: Stimulation of AT(2) receptor inhibited the binding of ST
ATs with sis-inducing element in c-fos promoter, resulting:in decreased c-f
os expression. Taken together, our results suggest that AT(2) receptor can
crosstalk negatively with multiple families of growth receptors by inhibiti
ng ERK and STAT activation.