Abstract
The activity of c-Jun, the major component of the transcription factor AP-1, is potentiated by amino-terminal phosphorylation on serines 63 and 73 (Ser-63/73). This phosphorylation is mediated by the Jun amino-terminal kinase (JNK) and required to recruit the transcriptional coactivator CREB-binding protein (CBP). AP-1 function is antagonized by activated members of the steroid/thyroid hormone receptor superfamily. Recently, a competition for CBP has been proposed as a mechanism for this antagonism. Here we present evidence that hormone-activated nuclear receptors prevent c-Jun phosphorylation on Ser-63/73 and, consequently, AP-1 activation, by blocking the induction of the JNK signaling cascade. Consistently, nuclear receptors also antagonize other JNK-activated transcription factors such as Elk-1 and ATF-2. Interference with the JNK signaling pathway represents a novel mechanism by which nuclear hormone receptors antagonize AP-1. This mechanism is based on the blockade of the AP-1 activation step, which is a requisite to interact with CBP. In addition to acting directly on gene transcription, regulation of the JNK cascade activity constitutes an alternative mode whereby steroids and retinoids may control cell fate and conduct their pharmacological actions as immunosupressive, anti-inflammatory, and antineoplastic agents.
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Activating Transcription Factor 2
-
Animals
-
Binding Sites
-
CREB-Binding Protein
-
Calcium-Calmodulin-Dependent Protein Kinases / metabolism*
-
Cyclic AMP Response Element-Binding Protein / metabolism
-
DNA-Binding Proteins*
-
Dexamethasone / pharmacology
-
Humans
-
JNK Mitogen-Activated Protein Kinases
-
MAP Kinase Kinase Kinase 1*
-
Mitogen-Activated Protein Kinases*
-
Nuclear Proteins / metabolism
-
Phosphorylation / drug effects
-
Protein Serine-Threonine Kinases / metabolism
-
Proto-Oncogene Proteins / metabolism
-
Receptors, Cytoplasmic and Nuclear / metabolism*
-
Receptors, Glucocorticoid / drug effects
-
Receptors, Glucocorticoid / genetics
-
Receptors, Glucocorticoid / metabolism
-
Receptors, Retinoic Acid / drug effects
-
Receptors, Retinoic Acid / genetics
-
Receptors, Retinoic Acid / metabolism
-
Signal Transduction
-
Trans-Activators*
-
Transcription Factor AP-1 / drug effects
-
Transcription Factor AP-1 / metabolism*
-
Transcription Factor AP-1 / radiation effects
-
Transcription Factors / metabolism
-
Transcriptional Activation
-
Ultraviolet Rays
-
ets-Domain Protein Elk-1
Substances
-
ATF2 protein, human
-
Activating Transcription Factor 2
-
Cyclic AMP Response Element-Binding Protein
-
DNA-Binding Proteins
-
ELK1 protein, human
-
Nuclear Proteins
-
Proto-Oncogene Proteins
-
Receptors, Cytoplasmic and Nuclear
-
Receptors, Glucocorticoid
-
Receptors, Retinoic Acid
-
Trans-Activators
-
Transcription Factor AP-1
-
Transcription Factors
-
ets-Domain Protein Elk-1
-
Dexamethasone
-
CREB-Binding Protein
-
CREBBP protein, human
-
Protein Serine-Threonine Kinases
-
Calcium-Calmodulin-Dependent Protein Kinases
-
JNK Mitogen-Activated Protein Kinases
-
Mitogen-Activated Protein Kinases
-
MAP Kinase Kinase Kinase 1
-
MAP3K1 protein, human