title: Transduction efficacy of Tat-Cu,Zn-superoxide dismutase is enhanced by copper ion recovery of the fusion protein.
abstract: We previously reported that Tat-Cu,Zn-superoxide dismutase (Tat-SOD) can be directly transduced into mammalian cells across the lipid membrane barrier. To enhance the therapeutic potential of Tat-SOD for the treatment of various disorders that are related to this antioxidant enzyme, the transduction efficacy of Tat-SOD should be heightened. Therefore, we investigated whether copper ion recovery of the fusion protein could enhance the transduction potential of Tat-SOD in cultured HeLa cells. The results showed that the transduction potential of Tat-SOD was markedly enhanced by copper ions, and moderately increased by zinc ions. Compared with Tat-SOD, the Tat-SOD that recovered the copper ion (CR-Tat-SOD) achieved a significant increase in intracellular concentration and enzymatic activity. Therefore, CR-Tat-SOD was transduced into HeLa cells in a rapid saturation manner, but Tat-SOD was shown in a time-dependent manner. With the higher transduction efficacy of CR-Tat-SOD than that of Tat-SOD, the transduced CR-Tat-SOD significantly increased the viability of HeLa cells that were pretreated with paraquat, an intracellular superoxide anion generator. Although the mechanism of the enhanced transduction of Tat-SOD by copper ions is still unanswered, these results indicate that copper ions facilitate the transduction of SOD. These then significantly increase the biological effectiveness of this antioxidant enzyme.
authors.affiliation: Department of Physiology, College of Medicine, Hallym University, Chunchon, Korea.
authors.forename: Won Sik
authors.initials: WS
authors.lastname: Eum
authors.forename: In Soon
authors.initials: IS
authors.lastname: Choung
authors.forename: A Yeon
authors.initials: AY
authors.lastname: Kim
authors.forename: Yong Je
authors.initials: YJ
authors.lastname: Lee
authors.forename: Jung Hoon
authors.initials: JH
authors.lastname: Kang
authors.forename: Jinseu
authors.initials: J
authors.lastname: Park
authors.forename: Kil Soo
authors.initials: KS
authors.lastname: Lee
authors.forename: Hyeok Yil
authors.initials: HY
authors.lastname: Kwon
authors.forename: Soo Young
authors.initials: SY
authors.lastname: Choi
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D002470:Cell Survival; D003300:Copper / Q000378:metabolism*; D015696:Gene Products, tat / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D008670:Metals / Q000378:metabolism; D010269:Paraquat / Q000378:metabolism; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D000975:Antioxidants; D015696:Gene Products, tat; D008670:Metals; D011993:Recombinant Fusion Proteins; D003300:Copper; D013482:Superoxide Dismutase; D010269:Paraquat