Regulation of the CREB coactivator TORC by the dual leucine zipper kinase at different levels

TY - JOUR

T1 - Regulation of the CREB coactivator TORC by the dual leucine zipper kinase at different levels

AU - Phu, Do Thanh

AU - Wallbach, Manuel

AU - Depatie, Chantal

AU - Fu, Accalia

AU - Screaton, Robert A

AU - Oetjen, Elke

N1 - Copyright © 2010 Elsevier Inc. All rights reserved.

PY - 2011/2

Y1 - 2011/2

N2 - CREB is a ubiquitously expressed transcription factor regulating gene expression via binding to a CRE DNA element. Previous work showed that the dual leucine zipper kinase (DLK) reduced CREB-dependent gene transcription at least in part via inhibition of the coactivator CBP. Here we demonstrate that DLK also inhibits CREB activity by affecting the interaction of CREB with its second coactivator TORC. DLK acted on TORC-dependent transcription by distinct mechanisms. An interaction between DLK and all three TORC isoforms was demonstrated by in vitro protein-protein interaction assays and in cells by coimmunoprecipitation that required the N-terminus of TORC and the leucine zipper of dimerized DLK. Overexpressed DLK induced the phosphorylation of TORC2 and TORC1 on Ser-171 and 167, respectively and on additional residues. Since a kinase-dead DLK mutant did not prevent the nuclear localization of TORC and did not reduce TORC transcriptional activity to the same extent as wild-type DLK, we suggest that DLK-induced phosphorylation of TORC contributes to DLK's inhibitory action. Both the interaction with and the phosphorylation of TORC by DLK might account for the reduced recruitment of TORC to a CRE containing promoter as revealed by chromatin immunoprecipitation assay. These results show for the first time the inhibition of TORC function by a mitogen-activated kinase. Given the dependence on TORC in CREB-directed gene transcription, DLK and its downstream kinases thus contribute to the finely tuned regulation of CREB-dependent effects.

AB - CREB is a ubiquitously expressed transcription factor regulating gene expression via binding to a CRE DNA element. Previous work showed that the dual leucine zipper kinase (DLK) reduced CREB-dependent gene transcription at least in part via inhibition of the coactivator CBP. Here we demonstrate that DLK also inhibits CREB activity by affecting the interaction of CREB with its second coactivator TORC. DLK acted on TORC-dependent transcription by distinct mechanisms. An interaction between DLK and all three TORC isoforms was demonstrated by in vitro protein-protein interaction assays and in cells by coimmunoprecipitation that required the N-terminus of TORC and the leucine zipper of dimerized DLK. Overexpressed DLK induced the phosphorylation of TORC2 and TORC1 on Ser-171 and 167, respectively and on additional residues. Since a kinase-dead DLK mutant did not prevent the nuclear localization of TORC and did not reduce TORC transcriptional activity to the same extent as wild-type DLK, we suggest that DLK-induced phosphorylation of TORC contributes to DLK's inhibitory action. Both the interaction with and the phosphorylation of TORC by DLK might account for the reduced recruitment of TORC to a CRE containing promoter as revealed by chromatin immunoprecipitation assay. These results show for the first time the inhibition of TORC function by a mitogen-activated kinase. Given the dependence on TORC in CREB-directed gene transcription, DLK and its downstream kinases thus contribute to the finely tuned regulation of CREB-dependent effects.

KW - Animals

KW - Cell Line

KW - Cricetinae

KW - Cyclic AMP Response Element-Binding Protein

KW - MAP Kinase Kinase Kinases

KW - Phosphorylation

KW - Promoter Regions, Genetic

KW - Protein Structure, Tertiary

KW - Transcription Factors

KW - Transcription, Genetic

U2 - 10.1016/j.cellsig.2010.10.001

DO - 10.1016/j.cellsig.2010.10.001

M3 - SCORING: Journal article

C2 - 20940047

VL - 23

SP - 344

EP - 353

JO - CELL SIGNAL

JF - CELL SIGNAL

SN - 0898-6568

IS - 2

ER -