Activation of ATF6 and an ATF6 DNA Binding Site by the Endoplasmic Reticulum Stress Response

doi:10.1074/jbc.M003322200

Activation of ATF6 and an ATF6 DNA Binding Site by the Endoplasmic Reticulum Stress Response*

From the Department of Biological Sciences, Columbia University, New York, New York 10027 and the ^§Department of Biological Chemistry and Howard Hughes Medical Institute, University of Michigan Medical Center, Ann Arbor, Michigan 48109

Abstract

ATF6 is a member of the basic-leucine zipper family of transcription factors. It contains a transmembrane domain and is located in membranes of the endoplasmic reticulum. ATF6 has been implicated in the endoplasmic reticulum (ER) stress response pathway since it can activate expression of GRP78 and other genes induced by the ER stress response. ER stress appears to activate ATF6 by cleavage from the ER membrane and translocation to the nucleus. However, direct DNA binding by ATF6 had not been demonstrated. In this report, we have identified a consensus DNA binding sequence for ATF6. This site is related to but distinct from ATF1/CREB binding sites. The site was placed in a reporter gene and was specifically activated by ATF6 overexpression and was strongly induced by the ER stress response. A dominant negative form of ATF6 blocked ER stress induction of both ATF6 site and GRP78 reporter genes. We further found that GAL4-ATF6 could be activated by ER stress. These results demonstrate that ATF6 is a direct target of the ER stress response. A proximal sensor of the ER stress response, human IRE1 (hIRE1), was sufficient to activate the ATF6 reporter gene, while a dominant negative form of hIRE1 blocked ER stress activation, suggesting that hIRE1 is upstream of ATF6 in the ER stress signaling pathway.

Footnotes

↵* This work was supported by NCI, National Institutes of Health Grant CA50329 (to R. P.).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.
↵‡ These two authors contributed equally to this work.
↵¶ To whom correspondence should be addressed: Dept. of Biological Sciences, Columbia University, Fairchild 813B, MC 2420, 1212 Amsterdam Ave., New York, NY 10027. Tel.: 212-854-8281; Fax: 212-854-7655; E-mail: mrp6@columbia.edu.
Published, JBC Papers in Press, June 15, 2000, DOI 10.1074/jbc.M003322200
↵2 W. Tirasophon and R. J. Kaufman, submitted for publication.
↵3 W. Tirasophon and R. J. Kaufman, unpublished results.
↵4 C. Zhu and R. P., unpublished results.
↵5 Y. Wang, J. Shen, and R. Prywes, unpublished results.
Abbreviations:

ER

endoplasmic reticulum

ERSE

ER stress response element

bZIP

basic-leucine zipper

aa

amino acids

PCR

polymerase chain reaction

CRE

cAMP-response element

CREB

cAMP-response element-binding protein

HA

hemagglutinin

hIRE1

human IRE1

mIRE1β

murine IRE1β

JNK

c-Jun N-terminal kinase

PS1

presenilin-1

TM

tunicamycin
- Received April 18, 2000.
- Revision received June 13, 2000.
The American Society for Biochemistry and Molecular Biology, Inc.