Protein S-Nitrosylation Measurement

G protein-coupled receptors (GPCRs) are the most abundant and diverse type of cell surface receptors. GPCR signal duration and amplitude are both controlled by posttranslational modifications, principally phosphorylation. Emerging evidence demonstrates that the GCPRs and their effectors are also subject to S-nitrosylation modification. Protein S-nitrosylation involves the covalent attachment of a nitric oxide (NO) group to the thiol side chain of select cysteine residues (S-NO) that impacts the protein function. Progress in this area of research has been hampered by technical limitations to measure biologic S-nitrosylation, but obstacles have been substantially alleviated over the past few years. The two most commonly used methods to detect S-nitrosylation require decomposition of the S-NO covalent bond and consequent detection of reduced thiol or released NO groups. In this review, we summarize current methods for detection of protein S-nitrosylation with a focus on the biotin switch technique and related methods.