Final Report Summary - ER ARCHITECTURE (Uncovering the Mechanisms of Endoplasmic Reticulum Sub-Domain Creation and Maintenance)
One of the hallmarks of eukaryotic cells is the presence of membrane-bound organelles. For many years the study of organelles focused on the advantages of creating distinct optimized environments best suited for promoting the various chemical reactions required to sustain life. However, for the entire cell to function as a unit, coordination and cooperation between the specialized organelles must take place.
One way in which organelles communicate and coordinate cellular functions is through interorganellar- or membrane- contact sites (MCS), where two organelles come into close apposition. These zones of close proximity have been visualized using electron microscopy (EM) techniques since the late 1950's, when an association between the endoplasmic reticulum (ER) and mitochondria was first described. Since then, the majority of contact sites that have been described have also visualized the ER as one of the two contact partners. This fact is, perhaps, not surprising given that ER membranes constitute up to 30% of cellular volume, and since the ER is essential for supplying most cellular lipids, in addition to its role in secretory protein maturation and ion homeostasis. MCS in the ER are formed in specialized sub- domains whose molecular machinery, structure, function and regulation are still poorly understood.
Cells are highly complex systems and as such require complex tools to study. Indeed, in the past years new tools have revolutionized our ability to move from the study of single genes to genomes, from single RNA molecules to global expression profiles and from single proteins to proteomes. We have now started a journey to systematically study an additional level of organization in cell biology – contact sites between organelles. We are doing this by combining novel systematic tools in the model organism yeast (Saccharomyces cerevisiae).
We have perfected methods for rapidly generating tailor made collections of mutants and screening them via a fully automated high content microscopy-screening platform. Our system allows us to choose any important organelle contact site and uncover both its resident proteins as well as the proteins affecting its structure, function and regulation. By focusing on all contact sites in the cell we are now starting to map the complexity of the cell and give a true representation of how organelles pass nutrients and information between each other.
Just like the prisoners chained in Plato’s cave only see simplified shadows on the wall and mistake those for reality, so have we, by being bound to old methodologies, been seeing only a simplified view of the reality of MCS. Our novel approach is enabling a new light to be shed on these basic questions, thus enabling a better understanding of the complex mechanisms that guide organelle biology in all cells.
One way in which organelles communicate and coordinate cellular functions is through interorganellar- or membrane- contact sites (MCS), where two organelles come into close apposition. These zones of close proximity have been visualized using electron microscopy (EM) techniques since the late 1950's, when an association between the endoplasmic reticulum (ER) and mitochondria was first described. Since then, the majority of contact sites that have been described have also visualized the ER as one of the two contact partners. This fact is, perhaps, not surprising given that ER membranes constitute up to 30% of cellular volume, and since the ER is essential for supplying most cellular lipids, in addition to its role in secretory protein maturation and ion homeostasis. MCS in the ER are formed in specialized sub- domains whose molecular machinery, structure, function and regulation are still poorly understood.
Cells are highly complex systems and as such require complex tools to study. Indeed, in the past years new tools have revolutionized our ability to move from the study of single genes to genomes, from single RNA molecules to global expression profiles and from single proteins to proteomes. We have now started a journey to systematically study an additional level of organization in cell biology – contact sites between organelles. We are doing this by combining novel systematic tools in the model organism yeast (Saccharomyces cerevisiae).
We have perfected methods for rapidly generating tailor made collections of mutants and screening them via a fully automated high content microscopy-screening platform. Our system allows us to choose any important organelle contact site and uncover both its resident proteins as well as the proteins affecting its structure, function and regulation. By focusing on all contact sites in the cell we are now starting to map the complexity of the cell and give a true representation of how organelles pass nutrients and information between each other.
Just like the prisoners chained in Plato’s cave only see simplified shadows on the wall and mistake those for reality, so have we, by being bound to old methodologies, been seeing only a simplified view of the reality of MCS. Our novel approach is enabling a new light to be shed on these basic questions, thus enabling a better understanding of the complex mechanisms that guide organelle biology in all cells.