The development of most organs and tissues requires signal transduction pathways such as Hedgehog (Hh), TGF1, Notch, and Wnt. Most studies have focused on established components of these pathways, information flow between them, and the relatively slow transcriptional changes they drive. We propose instead a new systematic approach to discovering important rapid responses to developmental signals, using Hh signaling as a test case.
Specific Aim 1 : We will identify immediate-early responses to an important developmental signal, Hedgehog, applying Stable Isotope Labeling with Amino acids in Cell culture (SILAC) and mass spectrometry to developmental regulation.
Specific Aim 2 : We will delineate the functions of "re-discovered" components in the Hh immediate-early response and explore novel leads that will provide insight into signal transduction. Summary: Comprehensive assessment of the earliest responses to major developmental signals will reveal new and critical aspects of the signal transduction mechanisms. Our tests using one pathway will set the stage for applying the approach to many others.
Hh and other signaling pathways used during development are universal among higher animals and important in human medicine. Damage to these pathways can cause human birth defects or cancer. It is therefore crucial to understand how the signals are regulated and interpreted by cells. This work will identify new ways to intervene, thereby enabling strategies that promote regenerative healing or prevent cancer. PUBLIC HEALTH RELEVANCE: Hedgehog (Hh), Wnt, and similar signaling pathways used during human development are universal among higher animals and damage to them are important causes of human birth defects and of childhood and adult cancer. It is crucial to understand how the signals are regulated and interpreted by cells in order to find new ways to promote regenerative healing or prevent cancer. We propose a systematic investigation of the very earliest events in Hh transduction, measuring Hh-induced changes in protein phosphorylation and abundance using Stable Isotope Labeling with Amino acids in Cell culture (SILAC) and mass spectrometry.