TY - JOUR
T1 - Adhesion regulates MAP kinase/ternary complex factor exchange to control a proliferative transcriptional switch
AU - Wozniak, Michele A
AU - Cheng, Catherine Q
AU - Shen, Colette J
AU - Gao, Lin
AU - Olarerin-George, Anthony O
AU - Won, Kyoung-Jae
AU - Hogenesch, John B
AU - Chen, Christopher S
N1 - Copyright © 2012 Elsevier Ltd. All rights reserved.
PY - 2012/11/6
Y1 - 2012/11/6
N2 - BACKGROUND: The ternary complex factors (TCFs; Elk1, Net, and Sap-1) are growth factor-responsive transcription cofactors of serum response factor (SRF) and are activated by MAP kinase (MAPK) phosphorylation to regulate immediate early gene transcription. Although cell adhesion also can regulate immediate early genes and proliferation, the mechanism for this effect has remained unexplored.RESULTS: Restricting adhesion and spreading of G(0)-synchronized cells on substrates with decreasing size of micropatterned islands of fibronectin suppressed serum-induced immediate early gene expression and S phase entry. Knockdown of Sap-1 decreased expression of the immediate early genes egr1 and fos and subsequent proliferation normally present with high adhesion, whereas knockdown of Net rescued egr1 and fos expression and proliferation normally suppressed by low adhesion. Chromatin immunoprecipitation studies showed increased occupancy of egr1 and fos promoters by Sap-1 with high adhesion, whereas low adhesion increased Net occupancy. This switch in TCF promoter binding was regulated by an adhesion-mediated switch in MAPK activity. Increasing adhesion enhanced serum-induced JNK activity while suppressing p38 activity, leading to increased Sap-1 phosphorylation and Net dephosphorylation, and switching Net with Sap-1 at egr1 and fos promoters to support proliferation. Microarray studies confirmed this switch in TCF regulation of proliferative genes and uncovered novel gene targets and functions coregulated by Sap-1 and Net.CONCLUSIONS: These data demonstrate a key role for the TCFs in adhesion-induced transcription and proliferation and reveal a novel MAPK/TCF transcriptional switch that controls this process.
AB - BACKGROUND: The ternary complex factors (TCFs; Elk1, Net, and Sap-1) are growth factor-responsive transcription cofactors of serum response factor (SRF) and are activated by MAP kinase (MAPK) phosphorylation to regulate immediate early gene transcription. Although cell adhesion also can regulate immediate early genes and proliferation, the mechanism for this effect has remained unexplored.RESULTS: Restricting adhesion and spreading of G(0)-synchronized cells on substrates with decreasing size of micropatterned islands of fibronectin suppressed serum-induced immediate early gene expression and S phase entry. Knockdown of Sap-1 decreased expression of the immediate early genes egr1 and fos and subsequent proliferation normally present with high adhesion, whereas knockdown of Net rescued egr1 and fos expression and proliferation normally suppressed by low adhesion. Chromatin immunoprecipitation studies showed increased occupancy of egr1 and fos promoters by Sap-1 with high adhesion, whereas low adhesion increased Net occupancy. This switch in TCF promoter binding was regulated by an adhesion-mediated switch in MAPK activity. Increasing adhesion enhanced serum-induced JNK activity while suppressing p38 activity, leading to increased Sap-1 phosphorylation and Net dephosphorylation, and switching Net with Sap-1 at egr1 and fos promoters to support proliferation. Microarray studies confirmed this switch in TCF regulation of proliferative genes and uncovered novel gene targets and functions coregulated by Sap-1 and Net.CONCLUSIONS: These data demonstrate a key role for the TCFs in adhesion-induced transcription and proliferation and reveal a novel MAPK/TCF transcriptional switch that controls this process.
KW - 3T3 Cells
KW - Adaptor Proteins, Vesicular Transport/genetics
KW - Animals
KW - Cell Adhesion/physiology
KW - Cell Line
KW - Cell Proliferation
KW - Early Growth Response Protein 1/genetics
KW - JNK Mitogen-Activated Protein Kinases/metabolism
KW - Mice
KW - Mitogen-Activated Protein Kinases/metabolism
KW - Phosphorylation
KW - Promoter Regions, Genetic
KW - Proto-Oncogene Proteins c-ets/genetics
KW - Proto-Oncogene Proteins c-fos/genetics
KW - Serum Response Factor/metabolism
KW - Sodium Channels/genetics
KW - Ternary Complex Factors/metabolism
KW - Transcription, Genetic
KW - p38 Mitogen-Activated Protein Kinases/metabolism
U2 - 10.1016/j.cub.2012.08.050
DO - 10.1016/j.cub.2012.08.050
M3 - Journal article
C2 - 23063436
SN - 0960-9822
VL - 22
SP - 2017
EP - 2026
JO - Current biology : CB
JF - Current biology : CB
IS - 21
ER -