PDBsum entry 1sse

Transcription activator

PDB id

1sse

Contents

			Protein chains

					35 a.a.


					86 a.a.

References listed in PDB file

Key reference

Title

Structural basis for redox regulation of yap1 transcription factor localization.

Authors

M.J.Wood, G.Storz, N.Tjandra.

Ref.

Nature, 2004, 430, 917-921. [DOI no: 10.1038/nature02790]

PubMed id

15318225

Abstract

The ability of organisms to alter their gene expression patterns in response to environmental changes is essential for viability. A central regulator of the response to oxidative stress in Saccharomyces cerevisiae is the Yap1 transcription factor. Upon activation by increased levels of reactive oxygen species, Yap1 rapidly redistributes to the nucleus where it regulates the expression of up to 70 genes. Here we identify a redox-regulated domain of Yap1 and determine its high-resolution solution structure. In the active oxidized form, a nuclear export signal (NES) in the carboxy-terminal cysteine-rich domain is masked by disulphide-bond-mediated interactions with a conserved amino-terminal alpha-helix. Point mutations that weaken the hydrophobic interactions between the N-terminal alpha-helix and the C-terminal NES-containing domain abolished redox-regulated changes in subcellular localization of Yap1. Upon reduction of the disulphide bonds, Yap1 undergoes a change to an unstructured conformation that exposes the NES and allows redistribution to the cytoplasm. These results reveal the structural basis of redox-dependent Yap1 localization and provide a previously unknown mechanism of transcription factor regulation by reversible intramolecular disulphide bond formation.



	Figure 1. Figure 1: Schematic Yap1 structures and in vivo analysis of Yap1-RD^GFP subcellular localization and oxidation. a, Yap1 contains three conserved regions: a basic leucine zipper DNA binding domain (bZIP), an n-CRD (Asn279 to Arg313) and a c-CRD, (Asn565 to Asn650). The NLS and NES are located at the N and C termini, respectively. The Cys303 -Cys598 and Cys310 -Cys629 disulphide bonds are shown with red lines. The oxidized Yap1-RD construct used for structure determination consisted of the protease-resistant n-CRD and c-CRD domains. Yap1-RD^GFP consisted of an SV40 NLS, GFP and residues Asn279 to Arg313 fused to residues Asn549 to Asn650 of Yap1. This fragment encompasses the n-CRD and c-CRD sequences plus a small amount of the native linker. b, Fluorescence microscopy of wild-type and gpx3 cells expressing Yap1-RD^GFP from the native YAP1 promoter on a CEN plasmid. c, Oxidized and reduced Yap1-RD^GFP extracted from wild-type and gpx3 cells. Exponentially growing cells were either exposed to H[2]O[2] or left untreated. Cell extracts were run on non-reducing and reducing SDS -PAGE gels and probed with a GFP antibody.		Figure 3. Figure 3: Inhibition of the Yap1 NES by the n- alpha-1 helix. a, Ribbon diagram of the Yap1-RD structure with the lowest energy shown in the same orientation as Fig. 2c. The n- 1 helix and the regions of c-CRD secondary structure are shown in cyan and dark blue, respectively. The NES residues Ile614, Val616, Leu619 and Leu623 are shown in green. These interact with other hydrophobic core residues of the c-CRD, which are shown in grey. b, The same ribbon diagram as in Fig. 3a, rotated to show the n- 1 residues. The amphipathic n- 1 helix contains conserved hydrophobic residues, Phe302, Met306 and Val309, shown in red. c, Surface representation of the c-CRD domain and its interaction with the hydrophobic residues in the n- 1 helix. The surface of the NES residues Ile614, Val616, Leu619 and Leu623 are shown in green and Phe302, Met306 and Val309 in red. d, Fluorescence microscopy of cells expressing Yap1-RD^GFP F302A, M306A and V309A mutants, untreated or treated with H[2]O[2] as carried out in Fig. 1b. e, Oxidized and reduced Yap1-RD^GFP F302A, M306A and V309A mutants extracted from exponentially growing cells untreated or treated with H[2]O[2]. The cell extracts were prepared as in Fig. 1c.

PROCHECK

	Headers