Integration of cellular signaling pathways in health and disease.

Introduction and general objective Understanding body and organ function in health and disease requires a thorough understanding of the signaling events that take place at the level of individual cells. Through a diversity of receptors, cells can sense and rapidly respond to changes in the cellular microenvironment. Receptor activation initiates a variety of complex molecular signaling pathways that ultimately shape the cellular response, triggering processes such as cell growth and differentiation, movement and contraction, transmitter release and cell death. Dysfunction of cellular signaling pathways lies at the basis of many human diseases including, but not limited to, cardiovascular and neurodegenerative diseases, infectious diseases, diabetes and cancer. The general objective of this project is to gain novel insights into the properties and interactions of different cellular signaling pathways under normal and pathological conditions. A better understanding of these processes forms the basis for the development of novel diagnostic and therapeutic strategies. Given the diversity and complexity of cellular signaling pathways, this ambitious objective requires a multifaceted and multidisciplinary team of researchers, and the development and use of innovative technologies. We therefore propose a network consisting of 7 Belgian and 2 foreign partners with highly complementary expertise in different fields of cell signaling, including Ca2+ signaling, phosphoinositide signaling, signaling via plasma membrane and nuclear receptors, chromatin signaling, phosphorylation/dephosphorylation and other post-translational modifications. The network has access to a broad range of cellular and molecular techniques as well as to relevant genetically modified cellular and mouse models, and patient material, to perform a translational approach. The network also includes a partner focusing on interactome biology and bioinformatics, which will be highly instrumental to integrate the data and analyze the cross-talk between signaling pathways. In addition to research possibilities, the network also offers unique and worthwhile opportunities for training and exchange of PhD students and postdoctoral personnel. This research network is based on the previous and successful IAP P6/28 consortium in which productive collaboration between the network partners was already firmly established. Brief overview of the planned research The planned research is subdivided in 6 coherent work packages (WPs), each focusing on a specific form of cell signaling and its interaction with other signaling pathways. WP 1: Mechanisms and (patho)physiological implications of ion transport processes. This work package plans to evaluate the function and regulation of different ion transport proteins in relation to their normal, physiological role as well as to etiology of diseases caused by dysfunction of these proteins. By studying the molecular mode of action of TRP (Transient Receptor Potential) channels and P-typeATPases, their cellular regulation and functional interaction with other ion transport proteins and signaling pathways, we expect to obtain important novel insight in the role of in ion transport processes with relevance to pain, inflammation, renal function, glucose homeostasis, heart failure and cancer. WP 2: Phosphorylation pathways in cell proliferation and cancer models. This work package aims to elucidate protein phosphorylation networks in several cancer models, focusing on the detailed mechanisms of action of specific tumor suppressive, oncogenic or angiogenic signaling molecules, including PP2A, PP1, Akt/PKB, AMPK, SHIP2, p53 and Stat3. Signaling pathways and signaling mechanisms in these various cancer models will be analyzed by classical molecular biology/cell biology approaches, and several omics strategies including interactomics and phosphoproteomics. These efforts may ultimately lead to the identification of novel targets for therapeutic intervention. WP 3: Ca2+ signaling in cell life and death. In this work package, we plan to investigate how Ca2+ signaling regulates crucial cellular processes including cell growth, cell death and autophagy. This involves 1) the role of intracellular Ca2+-release channels in apoptosis and their regulation by apoptosis regulator proteins of the Bcl-2 family; 2) the role of IP3 receptors and P-type ATPases in the induction and regulation of autophagy; and 3) the role of TRP channels in cell proliferation and neuronal outgrowth. The results from this work package will be of relevance to understanding the pathophysiology of cancer, cardiac hypertrophy and muscle dystrophy. WP 4: Control of cell growth and metabolism via phosphoinositide-dependent signaling pathways The focus of this work package is on the various enzymes that mediate the interconversion of membrane phosphoinositides, and their consequences for cell growth and metabolism. In particular, the functional regulation of PI kinases (e.g. the PI 5-kinase PIKfyve), inositol phosphate kinase (e.g. IPMK), PI phosphatases (e.g. the PI(3,4,5)P3 5-phosphatase SHIP2), and PI-regulated protein kinases (PKB/Akt and PDK1), and their role in cell growth, differentiation, glucose and fatty acid metabolism will be investigated. The results of this research will advance our knowledge of key regulatory mechanisms involved in the etiology of diabetes, obesity and the metabolic syndrome. WP 5: Signaling through chromatin-modifying enzymes This work package deals with how cellular signaling cascades affect gene expression patterns. Particular focus will be on covalent modifications of histone, including phosphorylation, acetylation and ubiquitination of specific residues in the N-terminal histone tails. A major effort will be to further delineate the mode of action of principal chromatin-modifying enzymes, including protein phosphatase-1 (PP1), histone deacetylases (HDACs) and deubiquinating enzymes (DUBs) in cellular signaling, and their roles in blood vessel development and cancer. WP 6: Analysis and mining of signaling complexes using contemporary interactomics. To understand the function and regulation of cell signaling proteins requires detailed knowledge of the larger protein complexes in which they participate. Given that each cell expresses several thousands of proteins, the number of potential protein-protein interaction complexes that can exist in a cell is immense. The combination of IAP network partners provides a unique set of molecular and bioinformatic techniques to identify and analyze protein-protein interactions on a large scale, as well as tools to specifically disrupt such interactions. In this work package, these approaches will be further developed and combined to identify and modify novel protein interactions for the some of the key proteins of WP1-5 (TRP channels, P-type ATPases, protein phosphatase/kinases, phosphoinositide metabolizing enzymes, receptors ). The functional and pathophysiological consequences of these interactions will then be further investigated within the different WP1-5.

Keywords:Pathways, Cellular, Integration

Disciplines:Laboratory medicine, Palliative care and end-of-life care, Regenerative medicine, Other basic sciences, Other health sciences, Nursing, Other paramedical sciences, Other translational sciences, Other medical and health sciences