John LaCava, Ph.D.
Research Associate Professor
Proteins are the chief effectors of cell biology and they rarely act alone. Much more commonly, proteins act within the context of multi-component complexes. To study the biochemical and structural characteristics of multi-component complexes, it is often necessary to transfer them from living cells into a test tube. However, once released from cells, many macromolecular interactions become unstable and rapidly decay, making the study of protein interactions intrinsically challenging. LaCava uses biochemistry and affinity proteomics to transfer intact macromolecules from cells to test tubes, enabling further downstream study. His team then explores how alterations in protein interactions can cause cellular dysfunction and lead to diseases.
Drawing inspiration from protein crystallography, LaCava developed a high-content screen that reveals optimal conditions for isolating target proteins in a variety of interaction states, exposing interaction partners in unprecedented depth and accuracy. This line of empirical investigation will be used to develop more comprehensive theories concerning the effective, predictable manipulation of protein complexes in vitro. In order to drive biological discovery, LaCava applies this approach to the study of protein complexes involved in eukaryotic RNA processing as well as those participating in the proliferation of parasitic genes known as LINE-1 retrotransposons. LINE-1 genes use a “copy and paste” mechanism to expand within the human genome, and they participate in a collection of RNA-protein and DNA-protein complexes that are not yet well understood. Moreover, LINE-1 retrotransposons are a newly recognized hallmark of cancer and LaCava’s team has successfully isolated LINE-1 macromolecules from patient tumors. The team aims to understand what cellular networks are important for LINE-1 proliferation, in order to identify its molecular vulnerabilities or, conversely, to use LINE-1 as a weapon against cancer cells that express it.