Current Research on Protein-Protein Interactions Among Auxin-Signaling Factors in Regulation of Plant Growth and Development

In many signaling pathways, various factors have been isolated by molecular genetic studies and wholegenome analysis. Understanding the interactions among these factors is crucial to understanding the signaling process as a whole. Recent studies on auxin signaling in the regulation of plant growth and development have discovered primary factors interacting with each other, and elucidated a very simple pathway modulating gene expression in response to auxin. However, these studies of auxin-signaling led to the question of how such a simple pathway generates multiple types of regulation in various processes of different cells throughout the life of a plant. Here, we provide an overview of recent progress in auxin biology focusing on protein-protein interactions in the signal transduction pathway and discuss various possibilities and approaches to resolve the issue.