ERC FUNDED PROJECTS

My objective is to understand the physiologic and medical importance of the posttranslational processing of CAAX proteins (e.g., K-RAS and prelamin A) and to define the suitability of the CAAX protein processing enzymes as therapeutic targets for the treatment of cancer and progeria. CAAX proteins undergo three posttranslational processing steps at a carboxyl-terminal CAAX motif. These processing steps, which are mediated by four different enzymes (FTase, GGTase-I, RCE1, and ICMT), increase the hydrophobicity of the carboxyl terminus of the protein and thereby facilitate interactions with membrane surfaces. Somatic mutations in K-RAS deregulate cell growth and are etiologically involved in the pathogenesis of many forms of cancer. A mutation in prelamin A causes Hutchinson-Gilford progeria syndrome—a pediatric progeroid syndrome associated with misshaped cell nuclei and a host of aging-like disease phenotypes. One strategy to render the mutant K-RAS and prelamin A less harmful is to interfere with their ability to bind to membrane surfaces (e.g., the plasma membrane and the nuclear envelope). This could be accomplished by inhibiting the enzymes that modify the CAAX motif. My Specific Aims are: (1) To define the suitability of the CAAX processing enzymes as therapeutic targets in the treatment of K-RAS-induced lung cancer and leukemia; and (2) To test the hypothesis that inactivation of FTase or ICMT will ameliorate disease phenotypes of progeria. I have developed genetic strategies to produce lung cancer or leukemia in mice by activating an oncogenic K-RAS and simultaneously inactivating different CAAX processing enzymes. I will also inactivate several CAAX processing enzymes in mice with progeria—both before the emergence of phenotypes and after the development of advanced disease phenotypes. These experiments should reveal whether the absence of the different CAAX processing enzymes affects the onset, progression, or regression of cancer and progeria.

1 689 600 €

Start date: 2008-06-01, End date: 2013-05-31

FateMapB aims to understand how the unique differentiation potential of fetal hematopoietic stem and progenitor cells (HSPCs) contribute to functionally distinct cell types of the adult immune system. While most immune cells are replenished by HSPCs through life, others emerge during a limited window in fetal life and sustain through self-renewal in situ. The lineage identity of fetal HSPCs, and the extent of their contribution to the adult immune repertoire remain surprisingly unclear. I previously identified the fetal specific RNA binding protein Lin28b as a post-transcriptional molecular switch capable of inducing fetal-like hematopoiesis in adult bone marrow HSPCs (Yuan et al. Science, 2012). This discovery has afforded me with unique perspectives on the formation of the mammalian immune system. The concept that the mature immune system is a mosaic of fetal and adult derived cell types is addressed herein with an emphasis on the B cell lineage. We will use two complementary lineage-tracing technologies to stratify the immune system as a function of developmental time, generating fundamental insight into the division of labor between fetal and adult HSPCs that ultimately provides effective host protection. Aim 1. Determine the qualitative and quantitative contribution of fetal HSPCs to the mature immune repertoire in situ through Cre recombination mediated lineage-tracing. Aim 2. Resolve the disputed lineage relationship between fetal derived B1a cells and adult derived B2 cells by single cell lineage-tracing using cellular barcoding in vivo. Aim 3. Characterize the mechanism and effector functions of Lin28b induced B1a cell development for assessing the clinical utility of inducible fetal-like lymphopoiesis. The implications of FateMapB extend beyond normal development to immune regeneration and age-related features of leukemogenesis. Finally, our combinatorial lineage-tracing approach enables dissection of cell fates with previously unattainable resolution.

1 499 905 €

Start date: 2017-10-01, End date: 2022-09-30

It is estimated that almost half of all enzymes utilize metal cofactors for their function, for example the respiratory complexes and the oxygen-evolving photosystem II, the most fundamental requirements for aerobic life as we know it. If we could mimic nature’s use of metals for harvesting sunlight, energy conversion and chemical synthesis it would eliminate the need for fossil fuels and greatly increase the possibilities of chemical industry while reducing the environmental impact. Achieving this type of chemistry is an outstanding testament to evolution and understanding it is a glaring challenge to mankind. These types of reactions are based on very challenging redox chemistry (involving one or several electrons). The key catalytic species are generally high-valent metal clusters with a varying ligand environment, provided by the protein and other bound molecules, that directly controls the reactivity of the inorganic core. To be able to understand and mimic this chemistry it is of central importance to know the geometric and electronic structures of the metal core as well as the entire ligand environment for these usually short-lived and very reactive intermediates. It has, for a number of reasons, proven extremely challenging to obtain these for protein-coordinated catalysts. The central goal of this project is to determine true and accurate geometric and electronic structures of high-valent di-nuclear Fe/Fe and Mn/Fe metal sites coordinated in protein matrices known to direct these for varied and important chemistry. By combining new X-ray diffraction based techniques with advanced spectroscopy we aim to define how the protein controls the entatic state as well as reactivity and mechanism for some of the most potent catalysts in nature. The results will serve as a basis for design of oxygen-activating catalysts with novel properties.

1 968 375 €

Start date: 2017-06-01, End date: 2022-05-31

The new global temperature goal calls for reliable quantification of present and future greenhouse gas (GHG) emissions, including climate feedbacks. Non-CO2 GHGs, with methane (CH4) being the most important, represent a large but highly uncertain component in global GHG budget. Lakes are among the largest natural sources of CH4 but our understanding of lake CH4 fluxes is rudimentary. Lake emissions are not yet routinely monitored, and coherent, spatially representative, long-term datasets are rare which hamper accurate flux estimates and predictions. METLAKE aims to improve our ability to quantify and predict lake CH4 emissions. Major goals include: (1) the development of robust validated predictive models suitable for use at the lake rich northern latitudes where large climate changes are anticipated in the near future, (2) the testing of the idea that appropriate consideration of spatiotemporal scaling can greatly facilitate generation of accurate yet simple predictive models, (3) to reveal and quantify detailed flux regulation patterns including spatiotemporal interactions and response times to environmental change, and (4) to pioneer novel use of sensor networks and near ground remote sensing with a new hyperspectral CH4 camera suitable for large-scale high resolution CH4 measurements. Extensive field work based on optimized state-of-the-art approaches will generate multi-scale and multi-system data, supplemented by experiments, and evaluated by data analyses and modelling approaches targeting effects of scaling on model performance. Altogether, METLAKE will advance our understanding of one of the largest natural CH4 sources, and provide us with systematic tools to predict future lake emissions. Such quantification of feedbacks on natural GHG emissions is required to move beyond state-of-the-art regarding global GHG budgets and to estimate the mitigation efforts needed to reach global climate goals.

2 000 000 €

Start date: 2017-04-01, End date: 2022-03-31