S-Nitrosylation of Platelet IIb3<
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- 作者：Geraldine M. Walsh ; Deirdre Leane ; Niamh Moran ; Tia E. Keyes ; Robert J. Forster ; Dermot Kenny ; Sarah O'Neill
- 刊名：Biochemistry
- 出版年：2007
- 出版时间：May 29, 2007
- 年：2007
- 卷：46
- 期：21
- 页码：6429 - 6436
- 全文大小：226K
- 年卷期：v.46,no.21(May 29, 2007)
- ISSN：1520-4995
文摘
The exact mechanisms regulating conformational changes in the platelet-specific integrin 
IIb
3are not fully understood. However, a role exists for thiol/disulfide exchange in integrin conformationalchanges leading to altered disulfide bonding patterns, via its endogenous thiol isomerase activity. Nitricoxide (NO) accelerates this intrinsic enzymatic activity and, in doing so, reverses the activational state ofthe integrin on the platelet surface toward a more unactivated one. We propose that it is an S-nitrosylation-induced "shuffling" of thiol/disulfide exchange that regulates this reversal of the activated state of theintegrin. In this study, we use Raman spectroscopy to explore S-nitrosylation of purified IIb3. UsingS-nitrosoglutathione (GSNO) as a model system, we identify Raman markers which show a direct interactionbetween NO and the thiol groups of the integrin and reveal many of the structural changes that occur inIIb3 in the course of not only its activation but also its deactivation. Key conformational changes aredetected within the integrin when treated with manganese (Mn2+), occurring mainly in the cysteine anddisulfide regions of the protein, confirming the importance of thiol/disulfide exchange in integrin activation.These changes are subsequently shown to be reversed in the presence of NO.
IIb3are not fully understood. However, a role exists for thiol/disulfide exchange in integrin conformationalchanges leading to altered disulfide bonding patterns, via its endogenous thiol isomerase activity. Nitricoxide (NO) accelerates this intrinsic enzymatic activity and, in doing so, reverses the activational state ofthe integrin on the platelet surface toward a more unactivated one. We propose that it is an S-nitrosylation-induced "shuffling" of thiol/disulfide exchange that regulates this reversal of the activated state of theintegrin. In this study, we use Raman spectroscopy to explore S-nitrosylation of purified IIb3. UsingS-nitrosoglutathione (GSNO) as a model system, we identify Raman markers which show a direct interactionbetween NO and the thiol groups of the integrin and reveal many of the structural changes that occur inIIb3 in the course of not only its activation but also its deactivation. Key conformational changes aredetected within the integrin when treated with manganese (Mn2+), occurring mainly in the cysteine anddisulfide regions of the protein, confirming the importance of thiol/disulfide exchange in integrin activation.These changes are subsequently shown to be reversed in the presence of NO.