EMBO Workshop: Membrane Contact Sites in Health and Disease.

The key evolutionary innovation of the Last Eukaryotic Common Ancestor consisted in the formation of physically and functionally specialized organelles that, through the compartmentalization of biological processes and signaling pathways, allowed life to adapt to new challenging and ever-changing environments. Similarly, the basic drive of the evolution of the eukaryotic cell consisted in using sites of contact between organelles as a platform for hosting biological or regulatory processes, thereby allowing life to evolve complexity through tissue and cellular specialization. For this reason, in the past decade, the study of interorganellar associations has attracted great interest and momentum. The emerging picture is one where organelles establish multiple and physically close or direct contacts with each other (Figure 1), through the activity of protein tethering complexes. This association, in turn, creates a spatially and functionally specialized subcellular compartment known as membrane contact sites (MCS); here, dedicated protein complexes allow MCS to execute and coordinate a plethora of physiological, metabolical, and cellular processes. The discovery of MCS forced cell biologists to profoundly reconsider the way organelles are studied because it introduced the concept that through a network of specialized membranes, organelles can control, and interact and cooperate with each other, thereby allowing for the orchestration of integrated and novel functions that individual organelles would otherwise be unable to perform. It is now clear that complex processes indeed occur at the interface between the endoplasmic reticulum (ER) and mitochondria, Golgi, endosomes, peroxisomes, lipid droplets, and the plasma membrane (PM). Moreover, heterotypic contact sites between other types of organelles also exist; they include, for instance, those between mitochondria and peroxisomes or endosomes/lysosomes (vacuole in yeast) or between PM and endosomes/lysosomes. Their ultrastructural and functional characterization has just started to emerge in the literature and at scientificmeetings. The parallel discovery of new types of MCS and of their role in key physiological and metabolic processes prompted a new community of cell biologists to emerge and to come together to work on two key objectives. One was that of launching a new scientific journal dedicated to becoming the gold-standard journal in this field: Contact. Under the leadership of Tim Levine (University College London, UK), Contact aims at addressing how MCS mediate and regulate cellular homeostasis and how impaired MCS biogenesis, regulation, or activity are linked to human diseases and metabolic conditions. The second objective was that of organizing and promoting the MCS field through the organization of world-class scientific meetings. So, under the leadership of Luca Scorrano (University of Padua, Italy), the very first meeting on MCS took place as an EMBO Workshop in Domus Maria, Italy, from September 15 to 18, 2016. Following the immense