Activation of Jun Kinase/Stress-activated Protein Kinase by GTPase-deficient Mutants of G
and G
(*)
- M. V. V. S. Vara Prasad(1)(§),
- Jonathan M. Dermott(1)(§),
- Lynn E. Heasley(2),
- Gary L. Johnson(3) and
- N. Dhanasekaran(1)(¶)
- From the (1) Fels Institute for Cancer Research and Molecular Biology and Department of Biochemistry, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, the
- (2) Department of Renal Medicine, University of Colorado Medical School, Denver, Colorado 80262, and the
- (3) Division of Basic Sciences, National Jewish Center for Immunology and Respiratory Medicine, Denver, Colorado 80206
- ¶ To whom correspondence should be addressed. Tel.: 215-707-1941; Fax: 215-707-2102.
Abstract
Signal transduction pathways regulated by G
and G
heterotrimeric G proteins are largely unknown. Expression of activated, GTPase-deficient mutants of α
and α
alter physiological responses such as Na
/H
exchanger activity, but the effector pathways controlling these responses have not been defined. We have found that the expression
of GTPase-deficient mutants of α
(α
Q229L) or α
(α
Q226L) leads to robust activation of the Jun kinase/stress-activated protein kinase (JNK/SAPK) pathway. Inducible α
Q229L and α
Q226L expression vectors stably transfected in NIH 3T3 cells demonstrated JNK/SAPK activation but not extracellular response/mitogen-activated
protein kinase activation. Transient transfection of α
Q229L and α
Q226L also activated the JNK/SAPK pathway in COS-1 cells. Expression of the GTPase-deficient mutant of αq (αqQ209L) but not αi (αiQ205L) or αs (αsQ227L) was also able to activate the JNK/SAPK pathway. Functional Ras signaling was required for α
Q229L and α
Q226L activation of the JNK/SAPK pathway; expression of competitive inhibitory N
Ras inhibited JNK/SAPK activation in response to both α
Q229L and α
Q226L. The results describe for the first time a Ras-dependent signal transduction pathway involving JNK/SAPK regulated by
α
and α
.
Footnotes
-
↵§ Contributed equally to this paper.
-
↵* This work was supported by NCI Core Program on Carcinogenesis Grant 5-P30-CA 12227 (to N. D.) and National Institutes of Health Grants GM 30324, CA 58187, and DK 37871 (to G. L. J.). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
-
↵1 The abbreviations used are:
- G protein
-
heterotrimeric guanine nucleotide binding protein
- JNK/SAPK
-
Jun kinase/stress-activated protein kinase
- ERK/MAPK
-
extracellular response/mitogen-activated protein kinase
- FGF
-
fibroblast growth factor
- FCS
-
fetal calf serum
- PAGE
-
polyacrylamide gel electrophoresis
- GST
-
glutathione S-transferase
- DMEM
-
Dulbecco's modified Eagle's medium
- FBS
-
fetal bovine serum
- HA
-
hemagglutinin
- IPTG
-
isopropyl-1-thio-β-D-galactopyranoside.
-
↵2A. M. Buhl, N. Dhanasekaran, and G. L. Johnson, unpublished observation.
-
- Received March 30, 1995.
- Revision received May 19, 1995.
- © 1995 by The American Society for Biochemistry and Molecular Biology, Inc.
