Study on lysosomes degradation of ricin A chain

AbstrcatObjective: To study lysosomes involvement in the degradation of ricin A chain. Methods: A lysosome-targeted singal KFERQ was added to the C terminus of rRTA by DNA recombinant technology.A pKK223.3 expression system in E.coli was used to produce recombinant ricine A chain (rRTA) and rRTA-KFERQ.Recombinant proteins were purified by affinity chromatography using Blue-Sepharose 6B.The cytotoxicity of recombinant proteins was measured by the MTT method. Results: Recombinant RTA-KFERQ was 49.87%,54.18% and 88.68% less cytotoxic than RTA itself on the threecell lines HEPG2,Hela and A549,respectively. Conclusion: Lysosomes can degrade,but not completely inactivate RTA in different cells,suggestingcells may have other degradation pathways for RTA.