ACR1, a yeast ATF/CREB repressor.

Vincent, Annette; Struhl, Kevin

doi:10.1128/mcb.12.12.5394

Cited by 74 publications

(69 citation statements)

References 58 publications

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“…Sko1p Homodimerization in Vivo Is Not Affected by Os- motic Stress-CREB transcription factors bind to their CRE recognition sequences as homo-or heterodimers (11,14). To determine whether dimerization of Sko1p in vivo plays a role in the regulation of this transcriptional repressor by osmotic stress, we assayed for Sko1p-Sko1p interaction by coprecipitation experiments.…”

Section: Deletion Analysis Of Sko1p: a Central Region (315-486) Is Rementioning

confidence: 99%

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Multiple Levels of Control Regulate the Yeast cAMP-response Element-binding Protein Repressor Sko1p in Response to Stress

Pascual-Ahuir¹,

Posas²,

Serrano³

et al. 2001

Journal of Biological Chemistry

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The Sko1p transcriptional repressor regulates a subset of osmoinducible stress defense genes in Saccharomyces cerevisiae by binding to cAMP-responsive elements. We have reported previously that in response to stress Sko1p is phosphorylated by the stress-activated Hog1p mitogenactivated protein kinase, which disrupts its interaction with the Ssn6p⅐Tup1p corepressor. Here we report that other mechanisms are essential for the regulation of the Sko1p repressor activity upon stress. The nuclear localization of Sko1p depends on the stress-inhibited protein kinase A (PKA). Sko1p is localized in the nucleus of unstressed cells, and it redistributes to the cytosol upon severe salt stress (1 M NaCl). Yeast mutants with low PKA activity localize Sko1p to the cytoplasm in the absence of stress and exhibit deregulated expression of cAMPresponsive element-regulated genes. The central part (315-486) of Sko1p, containing the PKA phosphorylation sites and the basic domain-leucine zipper domain, is essential for its nuclear localization. Salt-induced export of Sko1p from the nucleus is independent of Hog1p and of the Bcy1p regulatory subunit of PKA. Furthermore, phosphorylation by PKA slightly enhanced DNA binding affinity of Sko1p in vitro, whereas Sko1p dimerization in vivo is not regulated by stress. Sko1p repressor activity is associated to its binding to the Ssn6p⅐Tup1p complex. Interestingly, the Sko1p NH 2 terminus (1-315), containing the Hog1p phosphorylation sites, associates in vivo with Tup1p in the absence of Ssn6p, suggesting that Sko1p represses gene transcription by interacting directly with the Tup1p subunit of the Ssn6p⅐Tup1p complex.

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Section: Deletion Analysis Of Sko1p: a Central Region (315-486) Is Rementioning

confidence: 99%

“…In the yeast Saccharomyces cerevisiae the function of the CREB repressor Sko1p (10,11) has been identified recently. Sko1p represses gene expression from CRE promoter sequences of various osmoinducible genes such as ENA1 (Na ϩ extrusion ATPase) (12), HAL1 (ion homeostasis protein) (13), or GRE2 (homolog to plant isoflavonoid reductase) (14 -16).…”

mentioning

confidence: 99%

Multiple Levels of Control Regulate the Yeast cAMP-response Element-binding Protein Repressor Sko1p in Response to Stress

Pascual-Ahuir¹,

Posas²,

Serrano³

et al. 2001

Journal of Biological Chemistry

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“…We previously suggested that AP-1 and ATF/CREB proteins make similar DNA contacts but differ in half-site spacing preferences, and we predicted that the connection between the leucine zipper and basic region (residues 244-250) determines the flexibility and specificity of half-site spacing (13). In this regard, there is a consistent difference at the position corresponding to GCN4 residue 247: ATF/ CREB proteins have a positively charged residue (nearly always lysine), whereas AP-1 proteins do not (GCN4 contains a leucine) (16).…”

mentioning

confidence: 99%

Adaptability at the protein-DNA interface is an important aspect of sequence recognition by bZIP proteins.

Kim

Tzamarias

Ellenberger

et al. 1993

Proc. Natl. Acad. Sci. U.S.A.

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The related AP-1 and ATF/CREB families of transcriptional regulatory proteins bind as dimers to overlapping or adjacent DNA half-sites by using a bZIP structural motif. Using genetic selections, we isolate derivatives of yeast GCN4 that affect DNA-binding specificity at particular positions of the AP-1 target sequence. In general, altered DNAbinding specificity results from the substitution of larger hydrophobic amino acids for GCN4 residues that contact base pairs. However, in several cases, DNA binding by the mutant proteins cannot be simply explained in terms of the GCN4-AP-1 structure; movement of the protein and/or DNA structural changes are required to accommodate the amino acid substitutions. The quintet of GCN4 residues that make basepair contacts do not entirely determine DNA-binding specificity because these residues are highly conserved in the bZIP family, yet many of the bZIP proteins bind to distinct DNA sites. The a-helical fork between the GCN4 DNA-binding and dimerization surfaces is important for half-site spacing preferences, because mutations in the fork alter the relative affinity for AP-1 and ATF/CREB sites. The basic region in the protein-DNA complex is a long isolated a-helix, with no constraints from other parts of a folded domain. From all of these considerations, we suggest that small shifts in position and orientation or local deformations in the a-helical backbone distinguish one bZIP complex from another.The DNA-binding domains of most eukaryotic transcriptional regulatory proteins can be classified into a relatively small number of distinct structural classes. The bZIP motif (50-60 amino acid residues) consists of two distinct segments, the leucine zipper and the basic region (1). The C-terminal 30 residues form a two-stranded parallel coiled coil (the leucine zipper), which mediates dimerization (2). This leucine zipper symmetrically positions a divergent pair of basic-region a-helices, which pass through the major groove of each DNA half-site (3-6). Upon specific DNAcomplex formation, the bZIP segment undergoes a folding transition. The previously unfolded basic region becomes a-helical (7-9), and a quintet of conserved basic-region residues are positioned to make contacts with the DNA (6).Yeast GCN4 belongs to the AP-1 family of transcription factors that includes the Jun and Fos oncoproteins. The optimal AP-1-GCN4 recognition sequence, ATGA(C/ G)TCAT, consists of overlapping half-sites, which are nonequivalent because of the asymmetry imposed by the central C-G base pair (defined as position 0) (6, 10-12). GCN4 also binds with only slightly reduced affinity to the ATF/CREB sequence (ATGACGTCAT), in which the half-sites abut rather than overlap (13). In contrast, the structurally and immunologically related ATF/CREB transcription factors bind much more efficiently to ATF/CREB sites than to AP-1 sites (14). We have therefore proposed that AP-1 and ATF/ CREB proteins make similar DNA sequence-specific contacts but differ in their half-site spacing requirements (13).We previ...

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“…Repressors can inhibit transcription of their target genes by inhibiting the functions of activators by simply competing for the binding sites on the promoters (33)(34)(35). Repressors can also inhibit transcription through downregulation of the DNA-binding or transactivation activity of activators by forming complexes with them (36,37).…”

Section: Fig 6 Tpbf Is the Only Protein Responsible For Activation mentioning

confidence: 99%

Transcription of the Acanthamoeba TATA-binding Protein Gene

Huang

Bateman

1997

Journal of Biological Chemistry

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Transcription of the Acanthamoeba TATA-binding protein (TBP) gene is regulated by TBP promoter-binding factor (TPBF), a previously described transactivator that binds as a tetramer to the TBP Promoter Element (TPE) and stimulates transcription up to 10-fold in vitro. Here we report that TPBF also functions as a transcription repressor by binding to a negative cis-element, located between the TATA box and the transcription initiation site. The negative element, referred to as the nTPE, is structurally similar to the TPE, and its disruption increases the transcription potency of the TBP promoter. TPBF binds to the nTPE, as demonstrated by mobility shift assays. However, the binding affinity of TPBF for the nTPE is about 10-fold lower than for the TPE. When placed upstream of the TATA box, the nTPE has very little effect on transcription. However, it inhibits transcription when placed at several positions downstream of the TATA box. Mechanistic studies with the TBP promoter suggest that binding of TPBF to the nTPE not only prevents TBP from binding to the TATA box but also displaces bound TBP, thereby inhibiting further assembly of the preinitiation complex. These results suggest a mechanism in which the cellular TPBF concentration controls the level of TBP gene transcription and show that a single factor can be stimulatory, inhibitory, or neutral depending on the sequence and the context of its binding site.Modulation of gene expression at the level of transcription initiation is a major regulatory strategy for eukaryotic cells to control their responses to intra-or extracellular stimuli. Similarly, the level of production of housekeeping genes is also tightly regulated at the level of promoter efficiency. Transcription initiation on eukaryotic promoters involves the sequential addition of individual transcription factors through protein-DNA and/or protein-protein interactions (1). While accurate initiation of transcription from most eukaryotic class II promoters requires RNA polymerase II as well as a set of general transcription factors that includes TFIID, 1 TFIIB, TFIIF, TFIIE, and TFIIH (2), the level of transcription is mainly regulated by DNA-binding, sequence-specific transcription factors, also known as activators or repressors. Sequence-specific transcription factors bind to promoter elements via DNA-binding motifs and modulate transcription positively or negatively through direct or indirect (via coactivators) communication with the general transcription machinery (3). Most promoter elements are recognized by one single transcription factor. However, there are several examples in which one promoter element can be recognized by multiple factors or seemingly unrelated DNA elements can be recognized by a single factor (4 -9).TATA-Binding Protein (TBP) is a highly conserved eukaryotic basal transcription factor that is required for transcription by all three RNA polymerases both in vitro and in vivo (10 -12). TBP can associate with distinct sets of proteins (TBP-associated factors) thereby forming the compl...

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ACR1, a yeast ATF/CREB repressor.

Abstract: Members of the mammalian ATF/CREB family of transcription factors, which are associated with regulation by cyclic AMP and viral oncogenes, bind common DNA sequences (consensus TGACGTCA) via a bZIP domain.

Cited by 74 publications

References 58 publications

Multiple Levels of Control Regulate the Yeast cAMP-response Element-binding Protein Repressor Sko1p in Response to Stress

Multiple Levels of Control Regulate the Yeast cAMP-response Element-binding Protein Repressor Sko1p in Response to Stress

Adaptability at the protein-DNA interface is an important aspect of sequence recognition by bZIP proteins.

Transcription of the Acanthamoeba TATA-binding Protein Gene

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