4] Analysis and identification of protein-protein interactions using protein recruitment systems

Abstract

Publisher Summary The immense output of various genome-sequencing projects has provided the scientific community with numerous proteins with no assigned function. There is no single protein that functions in isolation within the cell, and protein–protein interactions serve as a general means to provide functional specificity and to control the activity of enzymes and signaling molecules. To achieve a better functional understanding of known and novel gene products, much current research activity in molecular cell biology is focused on the identification of interacting proteins and characterization of these interactions. To date, multiple methods exist to identify and characterize protein–protein interactions; however, few of them employ a genetic selection system in vivo such as the yeast two-hybrid system. The two-hybrid system is an excellent research tool and is commonly used to identify and characterize novel and known interaction partners for proteins of interest. Although powerful, the two-hybrid system, which is based on a transcriptional readout, exhibits several limitations and inherent problems. To overcome these problems and limitations, a cytoplasmic protein recruitment system designated the son of sevenless “(Sos) recruitment system” (SRS) has been developed. This and the related Ras recruitment system (RRS) take advantage of a general phenomenon in signal transduction—namely, that the generation of local high concentrations of a signaling intermediate can result in a dramatic increase in signaling activity.