Lysophosphatidic acid-induced c-fos up-regulation involves cyclic AMP response element-binding protein activated by mitogen- and stress-activated protein kinase-1 |
| |
Authors: | Lee Chang-Wook Kim Nam-Ho Choi Ho-Kyew Sun Yuanjie Nam Ju-Suk Rhee Hae Jin Chun Jerold Huh Sung-Oh |
| |
Institution: | Department of Molecular Biology, Helen L. Dorris Child and Adolescent Neuropsychiatric Disorder Institute, The Scripps Research Institute, La Jolla, California 92037, USA. |
| |
Abstract: | Lysophosphatidic acid (LPA) is a lipid growth factor that exerts diverse biological effects through its cognate receptor-mediated signaling cascades. Recently, we reported that LPA stimulates cAMP response element-binding protein (CREB) through mitogen- and stress-activated protein kinase-1 (MSK1). Previously, LPA has been shown to stimulate c-fos mRNA expression in Rat-2 fibroblast cells via a serum response element binding protein (SRF). However, involvement of CREB in LPA-stimulated c-fos gene expression is not elucidated yet. To investigate the CREB-mediated c-fos activation by LPA, various c-fos promoter-reporter constructs containing wild-type and mutated SRE and CRE were tested for their inducibility by LPA in transient transfection assays. LPA-stimulated c-fos promoter activation was markedly decreased when SRE and CRE were mutated. A dominant negative CREB significantly down-regulated the LPA-stimulated c-fos promoter activation. Chromatin immunoprecipitation assay revealed that LPA induced an increased binding of phosphorylated CREB and CREB-binding protein (CBP) to the CRE region of the endogenous c-fos promoter. Immunoblot analyses with various pharmacological inhibitors further showed that LPA induces up-regulation of c-fos mRNA level by activation of ERK, p38 MAPK, and MSK1. Taken together, our results suggest that CREB plays an important role in up-regulation of c-fos mRNA level in LPA-stimulated Rat-2 fibroblast cells. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|