|Título||Do liquid crystal-like phases of proteins organize membrane compartments?|
|Financiación Total||11,237,500 €|
We are in the midst of a revolution in our understanding of the internal organization of cells. In the 1950s we learned that lipid bilayer-based membranes serve as containers (organelles) within the cytoplasm. Now we are learning that liquid-like “membrane-less” organelles i.e. without any container, self-assemble based on “liquid-liquid” phase separations. We propose the seemingly radical idea that membrane-bounded organelles– like their membrane-less counterparts- are stabilized or even templated by analogous phase separations of their surface proteins into largely planar liquids akin to liquid crystals. Our unique Synergy team is organized specifically to test this “liquid crystal hypothesis” on the cell’s secretory compartments - ER exit sites (ERES) and the Golgi stack - by employing our complementary skills in physics, physical chemistry, biochemistry and cell biology. We hypothesize based on pilot experiments evidence that the ERES and Golgi selforganize as a multi-layered series of adherent liquid crystal-like phases of “golgin” and similar proteins which surround and enclose their membranes. Their differential adhesion and repulsion would specify the topology and dynamics of the membrane compartments. If this is true, it will literally rewrite the history of cell biology.
We will test the ‘liquid crystal’ hypothesis directly, systematically, and quantitatively on an unprecedented scale to either modify/disprove it or place it on a firm rigorous footing. Experiments (Aim 1) with 13 pure golgins in cis and trans pairwise combinations will establish their foundational physical chemistry. Surgically engineered changes in golgins/ERES proteins will alter the rank order (hierarchy) of their affinities for each other and link phase separation physics to cell biology (Aim 2) and be used to establish the structural basis of phase separations and their specificity, and the potential for self-assembly of wholly synthetic biological organelles (Aim 3).
|Título||Artificial mitochondria for health|
|Fecha de inicio||1/12/2013|
|Ficha||Acceder a la ficha completa del proyecto|
|Abstract||Mitochondria are cell organelles that provide the energetic requirements of the body. The majority of cellular ATP is produced by the membrane protein ATP synthase through a proton gradient across the mitochondrial inner membrane. Alterations in ATP synthase biogenesis can result in severe mitochondrial diseases affecting tissues with high energy requirements as brain and muscles. Mitochondrial diseases affect approximately 20 million people in the EU, causing 35 % of deaths during the first year of life of newborns. However, the available therapeutic approaches, are still extremely limited and there is no specific treatment for ATP synthase deficiencies. To improve the treatments currently available for mitochondrial diseases, the project will focus on the realization of artificial mitochondria (AM). Based on artificial lipid vesicles, AM will be fabricated by means of microfluidics methods, a powerful tool able to produce identical replicas of a given bio-inspired membrane-object. ATP synthase will be expressed and assembled within the lipid bilayer by encapsulating cell-free protein expression systems. To test the ability of AM as in-situ energy fabrication systems, targeting-AM will be endocytosed inside cultured cells and ATP synthesis will be triggered by taking advantage of the proton gradient provided by endosomes. Finally, by enclosing other plasmids encoding for diverse proteins, AM can be used as energy-factoring pockets to elicit protein expression just when internalized within cells. This novel approach may constitute an advanced new concept in gene therapy to more effectivelycreate breakthroughs in improving human health.|