C. Botteron et D. Dobbelaere, AP-1 AND ATF-2 ARE CONSTITUTIVELY ACTIVATED VIA THE JNK PATHWAY IN THEILERIA PARVA-TRANSFORMED T-CELLS, Biochemical and biophysical research communications, 246(2), 1998, pp. 418-421
Bovine T-cells infected by the protozoan parasite Theileria parva unde
rgo lymphoblastoid transformation, and proliferate in an uncontrolled
manner. While it has been established that the transcription factor NF
-kappa B is constitutively activated in T. parva-infected T-cells, Lit
tle is known about other transcription factors such as AP-1 and ATF-2.
We demonstrated increased binding activity to the AP-1 and CREB/ATF-2
consensus binding sites and show that the AP-1 complex is composed of
c-Jun, JunD, c-Fos, and ATF-2. The transcription factors c-Jun and AT
F-2 are constitutively phosphorylated in a parasite-dependent manner.
Both transcription factors can be phosphorylated by jun-NH2-terminal k
inase (JNK), but ATF-2 is also a substrate for p38. We determined whet
her p38 is activated in T. parva-infected cells. Immunoblot analysis a
nd inhibitor studies indicate that JNK, but not p38, is involved in AT
F-2 phosphorylation. Based on these results and previous studies, we c
onclude that parasite interference with mitogen-activated protein kina
se pathways is restricted to constitutive activation of JNK. (C) 1998
Academic Press.