Protein disulfide isomerase may facilitate the efflux of nitrite derived S-nitrosothiols from red blood cells

详细信息    查看全文

• 作者：Vasantha Madhuri Kallakunta ; Anny Slama-Schwok ; Bulent Mutus
• 关键词：BCA ; bicinchoninic acid ; EDTA ; ethylenediaminetetraacetic acid ; Hb ; hemoglobin ; NOx ; nitric oxide related species ; NP-40 ; nonyl phenoxypolyethoxylethanol ; PDI ; protein disulfide isomerase ; PMSF ; penylmethylsulfenylfluoride ; RBC ; red blood cells ; SNO-Hb ; S-nitrosohemoglobin ; SNO ; S-nitrosothiol ; SDS-PAGE ; sodium dodecyl sulfate ; poly acrylamide gel electrophoresis
• 刊名：Redox Biology
• 出版年：2013
• 年：2013
• 卷：1
• 期：1
• 页码：373-380
• 全文大小：898 K

文摘

Protein disulfide isomerase (PDI) is an abundant protein primarily found in the endoplasmic reticulum and also secreted into the blood by a variety of vascular cells. The evidence obtained here, suggests that PDI could directly participate in the efflux of NO⁺ from red blood cells (RBC). PDI was detected both in RBC membranes and in the cytosol. PDI was S-nitrosylated when RBCs were exposed to nitrite under 鈭?0% oxygen saturation but not under 鈭?00% oxygen saturation. Furthermore, it was observed that hemoglobin (Hb) could promote PDI S-nitrosylation in the presence of 鈭?00 nM nitrite. In addition, three lines of evidence were obtained for PDI-Hb interactions: (1) Hb co-immunoprecipitated with PDI; (2) Hb quenched the intrinsic PDI fluorescence in a saturable manner; and (3) Hb-Fe(II)-NO absorption spectrum decreased in a [PDI]-dependent manner. Finally, PDI was detected on the surface RBC under 鈭?00% oxygen saturation and released as soluble under 鈭?0% oxygen saturation. The soluble PDI detected under 鈭?0% oxygen saturation was S-nitrosylated. Based on these data it is proposed that PDI is taken up by RBC and forms a complex with Hb. Hb-Fe(II)-NO that is formed from nitrite reduction under 鈭?0% O₂, then transfers NO⁺ to either Hb-Cys 尾93 or directly to PDI resulting in S-nitroso-PDI which transverses the RBC membrane and attaches to the RBC surface. When RBCs enter tissues the S-nitroso-PDI is released from the RBC-surface into the blood where its NO⁺ is transferred into the endothelium thereby inducing vasodilation, suggesting local oxygen-dependent dynamic interplays between nitrite, NO and S-nitrosylation.