The focus of our group research interests is membrane fusion. Membrane fusion is a critical event in wide range of important biological processes including fertilization, muscle formation and repair, bone homeostasis and viral infection. Different fusions involve different proteins and membranes, depend on different triggers and can be as fast as a millisecond and as slow as several days. However, in every fusion event, the key aspects of the job of fusion-mediating protein machinery are dictated by general properties of the lipid bilayers, such as resistance to disruption and bending, and surface charge. In contrast to many groups, which focus on characterization of the fusogenic proteins (referred to as “fusion proteins” or “fusogens”), we are most interested in the mechanisms by which these proteins catalyze and drive energy-intensive lipid rearrangements underlying fusion. Thus, we often concentrate on lipid dependencies of fusion and/or on using these dependencies to dissect fusion pathways. To understand the mechanisms by which proteins break the continuity of the fusing membranes and then reassemble them in a new way, we need to identify the mechanistic motifs that are shared by disparate fusion reactions and those that are specific to each important biological fusion. We believe it is essential to complement in-depth analysis of the best-characterized fusion reactions with comparative analysis of less-explored fusion reactions. Fusion reactions mediated by well-studied envelope proteins of some viruses can be especially useful in exploring molecular mechanisms of protein-mediated membrane rearrangements. On the other hand, research on poorly understood fusion reactions, such as developmental cell-to-cell fusion, is likely to reveal new types of fusogens and fusion-triggering mechanisms. This research strategy motivates us to constantly broaden the assortment of fusion processes we are working on.