Grant: Project Grant

The growth of embryonic tissues is controlled by "growth factors" that are produced by discrete populations of cells, move through the tissues, and stimulate cells at a distance to grow and divide. In many cases, the movement of these factors has been shown to occur via long thin cellular projections called cytonemes that connect signal-sending cells and target cells. We have been characterizing a protein called Slik that promotes the growth of tissues in the fruit fly embryo, a powerful model system for genetic studies of this process. In preliminary experiments we found that Slik activity is to be controlled by a recently identified complex of proteins in cells called STRIPAK, that Slik protein is found in cytonemes, and that the STRIPAK complex is important for cytoneme formation. We are proposing to characterize the molecular details of how STRIPAK regulates Slik, and to determine what role both play in signaling through cytonemes in cultured cells and in fly embryos. Slik and STRIPAK complex proteins are also present in humans. We expect that our finding in flies will provide much-needed insights into the role these proteins are likely to play in cell-cell signaling in humans, both during normal physiology and in disease.