Monoclonal Antibodies as Site-Specific Probes for the Acetylcholine-receptor delta-Subunit Tyrosine and Serine Phosphorylation Sites

Preparation and application of polyclonal and monoclonal sequence-specific anti-phosphoamino acid antibodies

This unit discusses the issues that must be considered in the design, production, and characterization of polyclonal and monoclonal sequence-specific anti-phosphoamino acid antibodies. Protocols are provided for generating and purifying such antibodies, and methods are also provided for producing useful polyclonal antibodies in a non-purified form. Support protocols describe coupling of peptides or phosphotyrosine to a solid support for use in affinity chromatography. An example of the generation, purification, and characterization of two sequence-specific anti-phosphopeptide antibodies specific for different sequences of a single phosphoprotein is described. The cross-reactivity of such antibodies, which is a common problem with anti-peptide antibodies, is also discussed.

Production of antibodies that recognize specific tyrosine-phosphorylated peptides

Phosphorylation of tyrosine residues of various proteins plays an important role in regulation of the functional activities of proteins within the cell. Antibodies to specific tyrosine-phosphorylated peptides are a valuable tool for analysis of the localization and function of individual phosphoproteins. This unit describes the methods used to produce and screen monoclonal and polyclonal antibodies for specificity for only the phosphorylated state of a peptide.

Production of antibodies that recognize specific tyrosine-phosphorylated peptides

It is possible to produce anti-phosphopeptide antibodies (i.e., antibodies recognizing phosphorylated peptides) that recognize a protein only in its phosphorylated state, and that do not cross-react with either the cognate unphosphorylated protein or other phosphoproteins. This unit describes production of antibodies against tyrosine-phosphorylated peptides, with which the authors have the most expertise, but the principles discussed here also apply to peptides phosphorylated on serine and threonine. Protocols are presented for the production of polyclonal and monoclonal anti-phosphopeptide antibodies. Support protocols are provided for the coupling of peptides and phosphotyrosine to an affinity matrix (Affi-Gel 10); BSA-agarose affinity matrix is commercially available.