International Journal of Molecular Sciences Article TAT-Conjugated NDUFS8 Can Be Transduced into Mitochondria in a Membrane-Potential-Independent Manner and Rescue Complex I Deficiency Bo-Yu Lin 1, Gui-Teng Zheng 1, Kai-Wen Teng 1, Juan-Yu Chang 1, Chao-Chang Lee 1, Pin-Chao Liao 1 and Mou-Chieh Kao 1,2,* 1 Institute of Molecular Medicine, National Tsing Hua University, Hsinchu 30013, Taiwan;
[email protected] (B.-Y.L.);
[email protected] (G.-T.Z.);
[email protected] (K.-W.T.);
[email protected] (J.-Y.C.);
[email protected] (C.-C.L.);
[email protected] (P.-C.L.) 2 Department of Life Science, College of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan * Correspondence:
[email protected]; Tel.: +886-3-574-2472 Abstract: NADH dehydrogenase (ubiquinone) Fe-S protein 8 (NDUFS8) is a nuclear-encoded core subunit of human mitochondrial complex I. Defects in NDUFS8 are associated with Leigh syn- drome and encephalomyopathy. Cell-penetrating peptide derived from the HIV-1 transactivator of transcription protein (TAT) has been successfully applied as a carrier to bring fusion proteins into cells without compromising the biological function of the cargoes. In this study, we developed a TAT-mediated protein transduction system to rescue complex I deficiency caused by NDUFS8 defects. Two fusion proteins (TAT-NDUFS8 and NDUFS8-TAT) were exogenously expressed and Citation: Lin, B.-Y.; Zheng, G.-T.; purified from Escherichia coli for transduction of human cells. In addition, similar constructs were Teng, K.-W.; Chang, J.-Y.; Lee, C.-C.; generated and used in transfection studies for comparison.