Project Number:  Pomost/2010-1/1

Funds:  420.000 PLN

Duration:  2010-2013

Title of the project:  Functional characterization of the interactions between endosomal adaptor proteins APPL and Dvl proteins in the Wnt signaling pathway

Project leader:  Magdalena Banach-Orłowska, PhD

   There is a growing body of evidence highlighting the impact of endocytosis on cell signaling. It is commonly accepted that endocytosis is not only responsible for signal attenuation but it can also positively contribute to signal propagation. Many endocytic proteins actively participate in signal transduction, and these processes are currently intensively investigated.

   Multifunctional adaptor proteins APPL1 and APPL2 represent interesting examples of endocytic proteins involved in signaling. They have been shown to interact with many partners involved in various signaling pathways mediating apoptosis, cell survival, cell proliferation and chromatin remodeling. The data obtained in our laboratory indicate that APPL1 and APPL2 proteins function as positive regulators of the Wnt pathway.

   Wnt signaling governs crucial biological processes such as cell proliferation, adhesion or migration. Understanding the exact mechanisms by which Wnt signaling operates, including the role of APPL proteins in this process, is essential to fight diseases caused by abnormalities in this pathway.

   In this project we investigate the role of multifunctional endocytic proteins APPL1 and APPL2 in the regulation of the canonical (b-catenin dependent) and non-canonical (planar cell polarity; PCP) Wnt signaling pathways. We test the impact of APPL proteins on the initial stages of the canonical Wnt signaling route by studying their newly identified interaction with Dishevelled (Dvl) proteins, the known positive regulators of the Wnt pathway. Moreover, we are interested in studying the influence of APPL on the non-canonical pathway in the context of APPL-Dvl interactions, since Dvl proteins play a crucial role in the PCP pathway.

   In a broader sense, the proposed project should contribute to better understanding of mechanisms coordinating the endocytic and signaling machineries.

   With respect to the methodology used in our laboratory within this project, our main experimental system are cultured mammalian cells. We use a variety of methods, including cell fractionation, confocal microscopy, biochemical characterization of proteins and their post-translational modifications, identification of protein interacting partners, quantitative RT-PCR to investigate expression of Wnt target genes, and transcriptional reporters to measure the activity of the Wnt signaling pathway.

Project supported by Foundation for Polish Science in frame of the Parent-Bridge programme financed by the European Union via the European Regional Development Fund.