scholarly journals MAL and Ternary Complex Factor Use Different Mechanisms To Contact a Common Surface on the Serum Response Factor DNA-Binding Domain

2006 ◽  
Vol 26 (11) ◽  
pp. 4134-4148 ◽  
Author(s):  
Alexia-Ileana Zaromytidou ◽  
Francesc Miralles ◽  
Richard Treisman
Keyword(s):  
Dna Binding ◽  
Complex Formation ◽  
Ternary Complex ◽  
Serum Response Factor ◽  
Dna Bending ◽  
Binding Domain ◽  
Response Factor ◽  
Dna Binding Domain ◽  
Serum Response ◽  
Ternary Complex Factor

ABSTRACT The transcription factor serum response factor (SRF) interacts with its cofactor, MAL/MKL1, a member of the myocardin-related transcription factor (MRTF) family, through its DNA-binding domain. We define a seven-residue sequence within the conserved MAL B1 region essential and sufficient for complex formation. The neighboring Q-box sequence facilitates this interaction. The B1 and Q-box regions also have antagonistic effects on MAL nuclear import, but the residues involved are largely distinct. Both MAL and the ternary complex factor (TCF) family of SRF cofactors interact with a hydrophobic groove and pocket on the SRF DNA-binding domain. Unlike the TCFs, however, interaction of MAL with SRF is impaired by SRF αI-helix mutations that reduce DNA bending in the SRF-DNA complex. A clustered SRF αI-helix mutation strongly impairs MAL-SRF complex formation but does not affect DNA distortion in the MAL-SRF complex. MAL-SRF complex formation is facilitated by DNA binding. DNase I footprinting indicates that in the SRF-MAL complex MAL directly contacts DNA. These contacts, which flank the DNA sequences protected from DNase I by SRF, are required for effective MAL-SRF complex formation in gel mobility shift assays. We propose a model of MAL-SRF complex formation in which MAL interacts with SRF by the addition of a β-strand to the SRF DNA-binding domain β-sheet region, while SRF-induced DNA bending facilitates MAL-DNA contact.

scholarly journals Identification of transcriptional activation and inhibitory domains in serum response factor (SRF) by using GAL4-SRF constructs

1993 ◽  
Vol 13 (8) ◽  
pp. 4640-4647
Author(s):  
F E Johansen ◽  
R Prywes
Keyword(s):  
Amino Acids ◽  
Dna Binding ◽  
Transcriptional Activation ◽  
Serum Response Factor ◽  
Binding Domain ◽  
Response Factor ◽  
Dna Binding Domain ◽  
Activation Domain ◽  
Transcriptional Activation Domain ◽  
Serum Response

The binding of serum response factor (SRF) to the c-fos serum response element has been shown to be essential for serum and growth factor activation of c-Fos. Since SRF is ubiquitously expressed, it has been difficult to measure the activity of SRF introduced into cells. To assay for functions of SRF in cells, we have changed its DNA binding specificity by fusing it to the DNA binding domain of GAL4. Transfection of GAL4-SRF constructs into cells has allowed us to identify SRF's transcriptional activation domain as well as domains which inhibit this activity. First, we found that the transcriptional activation domain maps to between amino acids 339 and 508 in HeLa cells and to between amino acids 414 and 508 in NIH 3T3 cells. Second, we show that in the context of GAL4-SRF constructs, there are two separate domains of SRF that can inhibit its activation domain. Although these domains overlap the DNA binding and dimerization domains of SRF, these functions were not required for inhibition. Finally, we show that one of the inhibitory domains is modular in that it can also inhibit activation when it is moved amino terminal to GAL4's DNA binding domain in an SRF-GAL4-SRF construct. The implications of these inhibitory domains for SRF regulation are discussed.

Mutation of serum response factor phosphorylation sites and the mechanism by which its DNA-binding activity is increased by casein kinase II

1991 ◽  
Vol 11 (7) ◽  
pp. 3652-3659
Author(s):  
J R Manak ◽  
R Prywes
Keyword(s):  
Dna Binding ◽  
Serum Response Factor ◽  
Casein Kinase Ii ◽  
Binding Activity ◽  
Casein Kinase ◽  
Binding Domain ◽  
Response Factor ◽  
Dna Binding Domain ◽  
Dna Binding Activity ◽  
Serum Response

Casein kinase II (CKII) phosphorylates the mammalian transcription factor serum response factor (SRF) on a serine residue(s) located within a region of the protein spanning amino acids 70 to 92, thereby enhancing its DNA-binding activity in vitro. We report here that serine 83 appears to be the residue phosphorylated by CKII but that three other serines in this region can also be involved in phosphorylation and the enhancement of DNA-binding activity. A mutant that contained glutamate residues in place of these serines had only low-level binding activity; however, when the serines were replaced with glutamates and further mutations were made that increased the negative charge of the region, the resulting mutant showed a constitutively high level of binding equal to that achieved by phosphorylation of wild-type SRF. We have investigated the mechanism by which phosphorylation of SRF increases its DNA-binding activity. We have ruled out the possibilities that phosphorylation affects SRF dimerization or relieves inhibition due to masking of the DNA-binding domain by an amino-terminal region of the protein. Rather, using partial proteolysis to probe SRF's structure, we find that the conformation of SRF's DNA-binding domain is altered by phosphorylation.

scholarly journals Mutation of serum response factor phosphorylation sites and the mechanism by which its DNA-binding activity is increased by casein kinase II.

1991 ◽  
Vol 11 (7) ◽  
pp. 3652-3659 ◽  
Author(s):  
J R Manak ◽  
R Prywes
Keyword(s):  
Dna Binding ◽  
Serum Response Factor ◽  
Casein Kinase Ii ◽  
Binding Activity ◽  
Casein Kinase ◽  
Binding Domain ◽  
Response Factor ◽  
Dna Binding Domain ◽  
Dna Binding Activity ◽  
Serum Response

Casein kinase II (CKII) phosphorylates the mammalian transcription factor serum response factor (SRF) on a serine residue(s) located within a region of the protein spanning amino acids 70 to 92, thereby enhancing its DNA-binding activity in vitro. We report here that serine 83 appears to be the residue phosphorylated by CKII but that three other serines in this region can also be involved in phosphorylation and the enhancement of DNA-binding activity. A mutant that contained glutamate residues in place of these serines had only low-level binding activity; however, when the serines were replaced with glutamates and further mutations were made that increased the negative charge of the region, the resulting mutant showed a constitutively high level of binding equal to that achieved by phosphorylation of wild-type SRF. We have investigated the mechanism by which phosphorylation of SRF increases its DNA-binding activity. We have ruled out the possibilities that phosphorylation affects SRF dimerization or relieves inhibition due to masking of the DNA-binding domain by an amino-terminal region of the protein. Rather, using partial proteolysis to probe SRF's structure, we find that the conformation of SRF's DNA-binding domain is altered by phosphorylation.

scholarly journals Physical Interaction between the MADS Box of Serum Response Factor and the TEA/ATTS DNA-binding Domain of Transcription Enhancer Factor-1

2001 ◽  
Vol 276 (13) ◽  
pp. 10413-10422 ◽  
Author(s):  
Madhu Gupta ◽  
Paul Kogut ◽  
Francesca J. Davis ◽  
Narasimhaswamy S. Belaguli ◽  
Robert J. Schwartz ◽  
...  
Keyword(s):  
Dna Binding ◽  
Serum Response Factor ◽  
Binding Domain ◽  
Physical Interaction ◽  
Response Factor ◽  
Dna Binding Domain ◽  
Mads Box ◽  
Serum Response ◽  
Transcription Enhancer ◽  
Enhancer Factor

scholarly journals Identification of transcriptional activation and inhibitory domains in serum response factor (SRF) by using GAL4-SRF constructs.

1993 ◽  
Vol 13 (8) ◽  
pp. 4640-4647 ◽  
Author(s):  
F E Johansen ◽  
R Prywes
Keyword(s):  
Amino Acids ◽  
Dna Binding ◽  
Transcriptional Activation ◽  
Serum Response Factor ◽  
Binding Domain ◽  
Response Factor ◽  
Dna Binding Domain ◽  
Activation Domain ◽  
Transcriptional Activation Domain ◽  
Serum Response

The binding of serum response factor (SRF) to the c-fos serum response element has been shown to be essential for serum and growth factor activation of c-Fos. Since SRF is ubiquitously expressed, it has been difficult to measure the activity of SRF introduced into cells. To assay for functions of SRF in cells, we have changed its DNA binding specificity by fusing it to the DNA binding domain of GAL4. Transfection of GAL4-SRF constructs into cells has allowed us to identify SRF's transcriptional activation domain as well as domains which inhibit this activity. First, we found that the transcriptional activation domain maps to between amino acids 339 and 508 in HeLa cells and to between amino acids 414 and 508 in NIH 3T3 cells. Second, we show that in the context of GAL4-SRF constructs, there are two separate domains of SRF that can inhibit its activation domain. Although these domains overlap the DNA binding and dimerization domains of SRF, these functions were not required for inhibition. Finally, we show that one of the inhibitory domains is modular in that it can also inhibit activation when it is moved amino terminal to GAL4's DNA binding domain in an SRF-GAL4-SRF construct. The implications of these inhibitory domains for SRF regulation are discussed.

scholarly journals Ternary Complex Factor-Serum Response Factor Complex-Regulated Gene Activity Is Required for Cellular Proliferation and Inhibition of Apoptotic Cell Death

2004 ◽  
Vol 24 (23) ◽  
pp. 10340-10351 ◽  
Author(s):  
Elaine R. Vickers ◽  
Aneta Kasza ◽  
Isil Aksan Kurnaz ◽  
Anne Seifert ◽  
Leo A. H. Zeef ◽  
...  
Keyword(s):  
Cell Death ◽  
Ternary Complex ◽  
Serum Response Factor ◽  
Apoptotic Cell ◽  
Apoptotic Cell Death ◽  
Gene Activity ◽  
Immediate Early ◽  
Response Factor ◽  
Serum Response ◽  
Ternary Complex Factor

ABSTRACT Members of the ternary complex factor (TCF) subfamily of the ETS-domain transcription factors are activated through phosphorylation by mitogen-activated protein kinases (MAPKs) in response to a variety of mitogenic and stress stimuli. The TCFs bind and activate serum response elements (SREs) in the promoters of target genes in a ternary complex with a second transcription factor, serum response factor (SRF). The association of TCFs with SREs within immediate-early gene promoters is suggestive of a role for the ternary TCF-SRF complex in promoting cell cycle entry and proliferation in response to mitogenic signaling. Here we have investigated the downstream gene regulatory and phenotypic effects of inhibiting the activity of genes regulated by TCFs by expressing a dominantly acting repressive form of the TCF, Elk-1. Inhibition of ternary complex activity leads to the downregulation of several immediate-early genes. Furthermore, blocking TCF-mediated gene expression leads to growth arrest and triggers apoptosis. By using mutant Elk-1 alleles, we demonstrated that these effects are via an SRF-dependent mechanism. The antiapoptotic gene Mcl-1 is identified as a key target for the TCF-SRF complex in this system. Thus, our data confirm a role for TCF-SRF-regulated gene activity in regulating proliferation and provide further evidence to indicate a role in protecting cells from apoptotic cell death.

scholarly journals The pruned gene encodes the Drosophila serum response factor and regulates cytoplasmic outgrowth during terminal branching of the tracheal system

Development ◽  
1996 ◽  
Vol 122 (5) ◽  
pp. 1353-1362 ◽  
Author(s):  
K. Guillemin ◽  
J. Groppe ◽  
K. Ducker ◽  
R. Treisman ◽  
E. Hafen ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Ternary Complex ◽  
Serum Response Factor ◽  
Response Factor ◽  
Loss Of Function ◽  
Tracheal System ◽  
Expression Of Genes ◽  
Serum Response ◽  
Cytoplasmic Processes ◽  
Ternary Complex Factor

We identified a Drosophila gene, pruned, that regulates formation of the terminal branches of the tracheal (respiratory) system. These branches arise by extension of long cytoplasmic processes from terminal tracheal cells towards oxygen-starved tissues, followed by formation of a lumen within the processes. The pruned gene is expressed in terminal cells throughout the period of terminal branching. pruned encodes the Drosophila homologue of serum response factor (SRF), which functions with an ETS domain ternary complex factor as a growth-factor-activated transcription complex in mammalian cells. In pruned loss of function mutants, terminal cells fail to extend cytoplasmic projections. A constitutively activated SRF drives formation of extra projections that grow out in an unregulated fashion. An activated ternary complex factor has a similar effect. We propose that the Drosophila SRF functions like mammalian SRF in an inducible transcription complex, and that activation of this complex by signals from target tissues induces expression of genes involved in cytoplasmic outgrowth.

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