Cm. Horvath et al., INTERACTIONS BETWEEN STAT AND NON-STAT PROTEINS IN THE INTERFERON-STIMULATED GENE FACTOR-3 TRANSCRIPTION COMPLEX, Molecular and cellular biology, 16(12), 1996, pp. 6957-6964
The first STAT-containing transcription factor to be studied, the alph
a-interferon-induced ISGF3, is composed of a Stat1:2 heterodimer and a
weak DNA-binding protein, p48, that is a member of a growing family o
f proteins similar to the so-called interferon regulatory factor (IRF-
1). The p48 and Stat1:2 heterodimer do not associate stably in the abs
ence of DNA, but we show that amino acids similar to 150 to 250 of Sta
t1 and a COOH-terminal portion of p48 exhibit physical interaction, im
plying contact that stabilizes ISGF3. Moreover, amino acid exchanges w
ithin the Stat1 contact region diminish or abolish the functional acti
vity of Stat1. This protein interaction domain may be important in oth
er STAT proteins to recruit partners to multiprotein transcription fac
tors.