DJ-1 Modulates the p38 Mitogen-Activated Protein Kinase Pathway Through Physical Interaction With Apoptosis Signal-Regulating Kinase 1 Jung-Soon Mo, Jane Jung, Ji-Hye Yoon, Ji-Ae Hong, Mi-Yeon Kim, Eun-Jung Ann, Mi-Sun Seo, Yun-Hee Choi, and Hee-Sae Park * Hormone Research Center, School of Biological Sciences and Technology, Chonnam National University, Yongbong-dong, Buk-ku, Gwangju 500-757, Republic of Korea ABSTRACT DJ-1 has been reported as a gene linked to early onset familial Parkinson’s disease, and is functionally involved in transcriptional regulation and oxidative stress-induced cell death. To understand the role of DJ-1 in cellular stress, this study investigated DJ-1’s effect on stress- activated protein kinase signaling and H 2 O 2 -induced activation of apoptosis signal-regulating kinase 1 (ASK1). According to the results, the overexpression of DJ-1 inhibited H 2 O 2 -induced activation of ASK1 as well as the activation of downstream kinases in the p38 mitogen- activated protein kinase (MAPK) signaling cascade. The results of both in vivo binding and kinase studies have revealed that ASK1 is the direct target of DJ-1, whereas it has shown no effect on either MKK3 or p38. DJ-1 blocked both the homo-oligomerization of ASK1 and inhibited ASK1 activity. Taken together, our data strongly suggest that DJ-1, by directly inhibiting ASK1, may act as a negative regulator in ASK1 signaling cascades. J. Cell. Biochem. 110: 229–237, 2010. ß 2010 Wiley-Liss, Inc. KEY WORDS: DJ-1; APOPTOSIS SIGNAL-REGULATING KINASE 1 (ASK1); p38 MITOGEN-ACTIVATED PROTEIN KINASE (MAPK); PROTEIN–PROTEIN INTERACTION D J-1 (SP22/CAP-1/RS/PARK7) has been identified as a novel oncogenic protein that acts co-operatively with H-Ras [Nagakubo et al., 1997]. DJ-1 proteins play diverse roles in oncogenesis, male fertility, controlling protein–RNA interactions, regulating inflammation, controlling hypoxic stress, and modulat- ing androgen receptor transcription activity. Recently, DJ-1 was shown to be definitively causal in cases of familial Parkinson’s disease (PD). Homozygous and heterozygous mutations of DJ-1 were identified in patients with familial or sporadic PD [Bonifati et al., 2003; Hague et al., 2003; Moore et al., 2003; Abou-Sleiman et al., 2004; Hedrich et al., 2004]. DJ-1 protein can be reversibly or irreversibly oxidized and this modification strikingly increases susceptibility to oxidative stress [Meulener et al., 2006]. Several lines of evidence implicate DJ-1’s role in anti-oxidative stress reactions and that mutation of DJ-1 leads to cell death [Taira et al., 2004]. DJ-1 protects against oxidative stress and mitochondrial toxins in cell cultures and animal models. Thus far, several lines of evidence also appear to indicate that DJ-1 performs a cytoprotective function in cell death against oxidative stress by facilitating Akt/ PKB signaling and suppressing apoptosis signal-regulating kinase 1 (ASK1) signaling via sequestration of Daxx. Most recently, we reported that DJ-1 modulates the c-Jun N-terminal kinase (JNK) signaling pathway through negative regulation of the functions of mitogen-activated protein kinase/extracellular signal-regulated kinase kinase kinase 1 (MEKK1) via physical interaction [Mo et al., 2008]. ASK1 is a member of the mitogen-activated protein kinase kinase kinase family and activates SEK1–JNK1 and MKK3/MKK6-p38 signaling cascades [Ichijo et al., 1997]. ASK1 is a pivotal component in apoptosis induced by various cytotoxic stresses, including tumor necrosis factor (TNF-a), hydrogen peroxide (H 2 O 2 ), UV light, X-rays, heat shock, and growth factor- or serum withdrawal [Raingeaud et al., 1995; Xia et al., 1995; Kyriakis and Avruch, 1996; Verheij et al., 1996]. H 2 O 2 increases the dimeric form of ASK1, and then ROS-mediated dimerization of ASK1 causes ASK1 activation and apoptosis [Gotoh and Cooper, 1998]. The ASK1 signaling pathway performs a critical role in 6-hydroxydopamine-induced apoptosis in human neuroblastoma cells, and the inhibition of ASK1 signaling Journal of Cellular Biochemistry ARTICLE Journal of Cellular Biochemistry 110:229–237 (2010) 229 Grant sponsor: Korea Healthcare technology R&D Project, Ministry of Health & Welfare, Republic of Korea; Grant number: A080441. *Correspondence to: Hee-Sae Park, PhD, School of Biological Sciences and Technology, Chonnam National University, Yongbong-dong, Buk-ku, Gwangju, 500-757, Republic of Korea. E-mail: proteome@jnu.ac.kr Received 20 May 2009; Accepted 12 January 2010  DOI 10.1002/jcb.22530  ß 2010 Wiley-Liss, Inc. Published online 8 March 2010 in Wiley InterScience (www.interscience.wiley.com).