ABCB10 depletion reduces unfolded protein response in mitochondria.
Mitochondria have many functions, including ATP generation. The electron transport chain (ETC) and the coupled ATP synthase generate ATP by consuming oxygen. Reactive oxygen species (ROS) are also produced by ETC, and ROS damage deoxyribonucleic acids, membrane lipids and proteins. Recent analysis indicate that mitochondrial unfolded protein response (UPRmt), which enhances expression of mitochondrial chaperones and proteases to remove damaged proteins, is activated when damaged proteins accumulate in the mitochondria. In Caenorhabditis elegans, HAF-1, a putative ortholog of human ABCB10, plays an essential role in signal transduction from mitochondria to nuclei to enhance UPRmt. Therefore, it is possible that ABCB10 has a role similar to that of HAF-1. However, it has not been reported whether ABCB10 is a factor in the signal transduction pathway to enhance UPRmt. In this study, ABCB10 was depleted in HepG2 cells using small interfering RNA (siRNA), and the effect was examined. ABCB10 depletion upregulated ROS and the expression of ROS-detoxifying enzymes (SOD2, GSTA1, and GSTA2), and SESN3, a protein induced by ROS to protect the cell from oxidative stress. In addition, ABCB10 depletion significantly decreased expression of UPRmt-related mitochondrial chaperones (HSPD1 and DNAJA3), and a mitochondrial protease (LONP1). However, the putative activity of ABCB10 to export peptides from mitochondria was not lost by ABCB10 depletion. Altogether, these data suggest that ABCB10 is involved in UPRmtsignaling pathway similar to that of HAF-1, although ABCB10 probably does not participate in peptide export from mitochondria.
Department of Medical Technology, Faculty of Health Sciences, Kumamoto Health Science University, Kumamoto 861-5598, Japan. Electronic address: yano@kumamoto-hsu.ac.jp.
Masato
M
Yano
D018528:ATP-Binding Cassette Transporters / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D049069:ATP-Dependent Proteases / Q000235:genetics / Q000378:metabolism; D018834:Chaperonin 60 / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism; D050956:HSP40 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D056945:Hep G2 Cells; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism; D010084:Oxidation-Reduction; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics*; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism; D056811:Unfolded Protein Response; D000099156:Superoxide Dismutase 2; D000084622:Sestrins
D018528:ATP-Binding Cassette Transporters; D049069:ATP-Dependent Proteases; D018834:Chaperonin 60; D005982:Glutathione Transferase; D050956:HSP40 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D007527:Isoenzymes; D024101:Mitochondrial Proteins; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D013482:Superoxide Dismutase; D000099156:Superoxide Dismutase 2; C412459:ABCB10 protein, human; C120664:DNAJA3 protein, human; C060293:HSPD1 protein, human; C485523:SESN3 protein, human; D000084622:Sestrins; C484555:GSTA1 protein, human; C119995:glutathione S-transferase alpha; C000595973:LONP1 protein, human
ABCB10; Mitochondria; Mitochondria unfolded protein response; Redox; Signaling pathway