<i>Schizosaccharomyces pombe</i> Homologs of Human DJ-1 Are Stationary Phase-Associated Proteins That Are Involved in Autophagy and Oxidative Stress Resistance
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Abstract
<div><p>The Parkinson′s disease protein DJ-1 is involved in various cellular functions including detoxification of dicarbonyl compounds, autophagy and oxidative stress response. DJ-1 homologs are widely found in both prokaryotes and eukaryotes, constituting a superfamily of proteins that appear to be involved in stress response. <i>Schizosaccharomyces pombe</i> contains six DJ-1 homologs, designated Hsp3101-Hsp3105 and Sdj1 (previously named SpDJ-1). Here we show that deletion of any one of these six genes somehow affects autophagy during prolonged stationary phase. Furthermore, deletions of each of these DJ-1 homologs result in reduced stationary phase survival. Deletion of <i>sdj1</i> also increases the sensitivity of stationary-phase cells to oxidative stress induced by hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) whereas overexpression of <i>sdj1</i> has the opposite effect. Consistent with their role in stationary phase, expression of <i>hsp3101</i>, <i>hsp3102</i>, <i>hsp3105</i> and <i>sdj1</i>, and to a lesser extent <i>hsp3103</i> and <i>hsp3104</i>, is increased in stationary phase. The induction of <i>hsp3101</i>, <i>hsp3102</i>, <i>hsp3105</i> and <i>sdj1</i> involves the Sty1-regulated transcription factor Atf1 but not the transcription factor Pap1. Our results firmly establish that <i>S</i>. <i>pombe</i> homologs of DJ-1 are stationary-phase associated proteins and are likely involved in autophagy and antioxidant defense in stationary phase of <i>S</i>. <i>pombe</i> cells.</p></div