Nitric oxide-mediated reversible regulation of protein tyrosine phosphatases through cysteine S-nitrosylation
Date Issued
2006
Date
2006
Author(s)
Huang, Yi-Fen
DOI
zh-TW
Abstract
It has been well recognized that nitric oxide (NO) regulates important biological processes in a cGMP-dependent manner. In addition, substantial evidence has shown that NO may participate in the regulation of signal transduction through Cys S-nitrosylation of various signaling pathway. Among potential NO targets, the protein tyrosine phosphatases (PTPs) were proposed to be susceptible to nitorsylation due to the unique low pKa character of their essential catalytic Cys residue. In the present study, we initially explored the molecular mechanism for S-nitrosylation of PTP1B, a prototypic PTP which controls a diverse array of signaling pathways. Our results demonstrated that the treatment of PTP1B with S-nitroso-N-acetylpencillamine (SNAP), an NO donor, led to solely reversible inhibition, rather than facilitating the formation of permanently inactive form of phosphatase. In addition, the S-nitrosylated Cys residues of PTP1B were directly identified by advanced mass spectrometry analysis. Interestingly, S-nitrosylation of the catalytic Cys215 prevented PTP1B from irreversible oxidation, thus providing a protective effect for the phosphatase during an oxidative burst. We further investigated the regulation of PTPs by NO in a cellular context. For this purpose, an in-gel phosphatase activity assay was employed to analyze the redox status of endogeneous PTPs expressed in EAhy926 endothelial cells. We demonstrated that multiple PTPs were reversibly nitrosylated and inactivated in these ECs treated with either SNAP (exogenous NO donor) or VEGF (endogenous NO donor). Furthermore, cellular glutathione level played an essential role for an efficient reduction of nitrosylated PTPs. The data also show that the NO-mediated inactivation of PTPs was concomitant with an increased tyrosine phosphorylation level of cellular proteins. Our results not only reveal the fundamental basis for the mechanistic detail of Cys nitrosylation of PTPs, but offer insights into a novel biological role of NO that may govern tyrosine phosphorylation-dependent signaling through regulation of cellular PTPs.
Subjects
酪氨酸去磷酸酶
一氧化氮
Nitric oxide
S-nitrosylation
protein tyrosine
Type
other
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