Tandem Affinity Purification (TAP) Tags

Abstract

Cells respond to myriad intra- and extracellular cues often by modulating the formation and function of heteromeric protein complexes (PCs). Thus, developing a comprehensive picture of cellular behavior and understanding biological responses requires characterization of PCs in their proper cellular context. Tandem affinity purification (TAP) is a two-step affinity purification method that aids in rapid isolation of PCs under native conditions. Since its original description in yeast, numerous variations of the affinity tag combinations have been developed to address some of the inadequacies of the original method and to accommodate the expanding scope of applications. The TAP, in combination with mass spectrometry, has paved the way for large-scale characterization of PCs and the dynamic protein interaction networks (PINs) in diverse organisms over the past decade.

Key Concepts:

• Characterizing the architecture of protein complexes and protein interaction networks is essential to decipher the cellular responses to environmental cues.

• Sequential affinity purification steps employed in tandem-affinity purification aid in specific and rapid purification of protein complexes.

• Standardized TAP protocols could benefit both intra- and inter-laboratory reproducibility of large-scale protein complex characterization efforts.