Activation of the HIV-1 Long Terminal Repeat by Cytokines and Environmental Stress Requires an Active CSBP/p38 MAP Kinase

doi:10.1074/jbc.271.48.30864

Activation of the HIV-1 Long Terminal Repeat by Cytokines and Environmental Stress Requires an Active CSBP/p38 MAP Kinase*

From the Department of ^‡ Molecular Immunology,
^¶ Molecular Genetics, and
^∥ Cellular Biochemistry, SmithKline Beecham Pharmaceuticals, King of Prussia, Pennsylvania 19406

** To whom correspondence should be addressed. Tel.: 610-270-7691; Fax: 610-270-7962.

↵^§ This author contributed equally to the work.

Abstract

The human immunodeficiency virus, type 1 (HIV-1) promoter is known to be activated by proinflammatory cytokines and UV light. These stimuli also activate various members of the mitogen-activated protein kinase family, including JNK/SAPK and CSBP/p38. In HeLa cells containing an integrated HIV-1 long terminal repeat (LTR) -driven reporter, we now show that the specific p38 inhibitor, SB203580, inhibits activation of the HIV-1 LTR by interleukin-1, tumor necrosis factor, UV light, and osmotic stress. Inhibition was 70-90% in all but the case of tumor necrosis factor stimulation, where inhibition was 50%. Each of these stimuli activated p38, which was inhibited by SB203580 in vitro and in vivo with an IC₅₀ (between 0.1 and 1 μM) similar to that required to inhibit transcription. In contrast, SB203580 had no effect on JNK, which was also activated by these stimuli. The NFκB sites in the HIV-1 LTR were required for a response to cytokines but not to UV, and SB203580 remained capable of inhibiting UV activation in the absence of the NFκB sites. Studies in which SB203580 was added at different times relative to UV stimulation suggested that the critical p38-mediated phosphorylation event occurred between 2 and 4 h after UV treatment. These data indicate that p38 is required for HIV-1 LTR activation but that the action of p38 is delayed, presumably due to substrate unavailability or inaccessibility.

Footnotes

↵* The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵¹ The abbreviations used are:

HIV-1

human immunodeficiency virus, type 1

EGF

epidermal growth factor

hsp

heat shock protein

IL-1

interleukin-1

JNK

c-jun N-terminal kinase

LTR

long terminal repeat

MAP

mitogen-activated protein kinase

MAPKAP

MAP kinase-activated protein kinase

PCR

polymerase chain reaction

TNF

tumor necrosis factor

CAT

chloramphenicol acetyltransferase

CSBP

CSAID™ binding protein

SAPK

stress-activated protein kinase.
↵² L. Shapiro and C. A. Dinarello, personal communication.
↵³ S. Kumar, unpublished observations.
- Received June 27, 1996.
- Revision received September 5, 1996.