Dissection of Signaling Pathways

Abstract

Basic biological scientists are often concerned with understanding the cascade of events that lead to specific biological end points, such as how cells are driven to enter cell division and the various proteins that control this process, or how the response to hypoxic conditions is regulated. Often this involves examining the ability of proteins to undergo multiple protein-protein interactions and subsequently determining which specific complexation events are key to a given cellular response. One of the most utilized approaches to dissect the key protein-protein interaction events utilizes the introduction of point mutation(s) into a cDNA that can express a mutated protein, this can lead to the disruption of a specific protein-protein interaction. An example can be found in the studies by Lamarche et al., who examined the ability of Rac and cdc42 mutants to interact with either Ser/Thr kinase p65^PAK or Ser/Thr kinase p160_ROCK [45]. By introducing mutations in Rac or cdc42 that disrupted binding of a specific kinase, they were able to demonstrate which kinase cascades have to be activated to obtain a biological response such as G1 cell cycle progression.