A Newly Identified Essential Complex, Dre2-Tah18, Controls Mitochondria Integrity and Cell Death after Oxidative Stress in Yeast

Abstract

A mutated allele of the essential gene TAH18 was previously identified in our laboratory in a genetic screen for new proteins interacting with the DNA polymerase delta in yeast [1]. The present work shows that Tah18 plays a role in response to oxidative stress. After exposure to lethal doses of H2O2, GFP-Tah18 relocalizes to the mitochondria and controls mitochondria integrity and cell death. Dre2, an essential Fe/S cluster protein and homologue of human anti-apoptotic Ciapin1, was identified as a molecular partner of Tah18 in the absence of stress. Moreover, Ciapin1 is able to replace yeast Dre2 in vivo and physically interacts with Tah18. Our results are in favour of an oxidative stress-induced cell death in yeast that involves mitochondria and is controlled by the newly identified Dre2-Tah18 complex.

Molecular view of an electron transfer process essential for iron–sulfur protein biogenesis

“…This behavior indicates that the unstructured C-terminal region of anamorsin interacts with oxidized FMN-Ndor1, whereas the N-terminal, well-structured domain of anamorsin is not involved in protein-protein recognition. Accordingly, no chemical shift perturbations were observed when oxidized, 15 N-labeled FMN-Ndor1 was titrated with the N-terminal domain of [2Fe-2S]-anamorsin produced as an independent domain (Fig. S4).…”

“…2A). 1 H-and 13 C-detected triple resonance experiments tailored to assign fast relaxing 1 H, 15 N, and 13 C resonances were also performed (22)(23)(24)(25). An assignment can be proposed for 7 of the 10 NH resonances observed only in the 1 H-15 N IR-HSQC-AP experiment ( Fig.…”

“…This is based on the structural characterization of the FMN-binding domain of Ndor1 and of the C-terminal region (linker and CIAPIN1 domain) of anamorsin containing the [2Fe-2S] cluster in the oxidized state ([2Fe-2S]-anamorsin, hereafter) and on the identification of the protein regions between [2Fe-2S]-anamorsin and the FMN-binding domain of Ndor1 responsible for the formation of their stable complex and of those regions interacting in the electron transfer process. The molecular model of the electron transfer process proposed here provides significant information on the functional processes in which the anamorsinNdor1 interaction has been implicated, i.e., the assembly of ISCs (13) and diferric (17) proteins and the regulation of cell survival/ death mechanisms (15,16). This article is a PNAS Direct Submission.…”

“…The [2Fe-2S] cluster of Dre2 receives electrons from a cytosolic diflavin reductase, termed Tah18 (13), which contains a FAD and a FMN prosthetic group, respectively, bound in two distinct structural domains, to accept electrons from NADPH (14). Dre2 and Tah18 are protein partners forming a stable complex in vivo (13,15). The C-terminal region of Dre2 (residues 173-348) is fundamental to form, both in vivo and in vitro, the stable complex with Tah18 (16).…”

“…However, the molecular basis of these processes has not been elucidated. The electron transfer process observed in yeast is possibly conserved in humans as the functional orthologs, NADPH-dependent diflavin oxidoreductase 1 (Ndor1) and anamorsin, form a stable complex in vivo that can functionally replace the Tah18-Dre2 complex in yeast cells (13,15). Similar to Dre2 but with significant differences in the number of residues, anamorsin contains two domains (an N-terminal domain of 172 residues and a C-terminal domain of 90 residues, named cytokine-induced apoptosis inhibitor 1 (CIAPIN1) hereafter, which contains two highly conserved cysteine rich motifs, CX 8 CX 2 CXC and CX 2 CX 7 CX 2 C) connected by a linker of 51 residues (18).…”