Preparation of tau from the peripheral nerve: presence of insoluble low molecular weight tau with high phosphorylation

Generation and utilization of phosphorylation state-specific antibodies to investigate signaling pathways

Phosphorylation state-specific antibodies can be of great use, for example, in studying individual steps within a given signal transduction pathway. This unit presents a general approach to the generation and purification of phosphorylation state-specific antibodies. In addition to their ability to detect phosphorylation at a particular key site, these antibodies are often more sensitive for biochemical studies. Besides their application in immunoblotting procedures, activation state-specific antibodies can be used as immunohistochemical reagents. Thus, critical changes in phosphorylation can be monitored as described on an individual cell basis or in fixed tissue sections. Such antibodies can be used to address fundamental questions about signal transduction pathways during physiologic events that cannot be resolved by more conventional methodologies.

Preparation and application of antibodies to phosphoamino acid sequences

In this review, we describe methods to generate and characterize sequence-specific phosphoamino acid antibodies. Several of the early contributions regarding the utility of such antibodies are summarized. Three antiphosphopeptide antibodies derived from sequences of the Bcr protein are described. They are anti-Bcr pSer-354, anti-Bcr pTyr-328, and anti-Bcr pTyr-360. These anti-Bcr phosphopeptide antibodies are directed toward phosphorylated sequences encoded by the first exon of the BCR gene, which is the critical portion of the Bcr sequence present in the Bcr-Abl oncoprotein. Using these antibodies, we established/confirmed the in vivo phosphorylation of Ser-354, Tyr-328, and Tyr-360 in Bcr and Bcr-Abl proteins. The cross-reactivity of these antibodies, which is a common problem with antipeptide antibodies, was also investigated and discussed.