Proteolytic switches in muscle biology

Proteolysis is a radical form of post-translational modification that can have an immediate impact on protein function, localization, and interaction. In a typical mammalian genome, there are 500-600 proteases that can transform cell morphology, behavior, and even identity. We are particularly interested in ones that play a role in myotube formation, muscular dystrophies, rhabdomyosarcoma, and cachexia. Our model systems include C2C12 cells, primary myoblasts, patient-derived iPSCs, and zebrafish. In addition to standard cell biology approaches, we make use of chemical biology and advanced microscopy techniques.

On-going projects

  • Identification of proteases involved in myogenesis and myopathies

    We aim to (1) discover novel proteases that play a key role in the formation, degeneration, or regeneration of skeletal muscle, (2) identify their substrates, and (3) develop inhibitors/activators. Our key approaches include subcellular-resolution activity-based protein profiling and N-/C-terminomics.

  • Focal adhesion proteins inside the nucleus

    We discovered that multiple focal adhesion proteins (e.g., zyxin, FAK, Hic-5, and paxillin) become transiently nuclear during myoblast-to-myotube transition. We want to understand how their nuclear translocation facilitates myogenesis. We are currently analyzing the interactomes of these focal adhesion proteins at the adhesion site vs in the nucleus.

  • Tool development: coIP/MS of endogenous zebrafish proteins

    We have established a subcellular-resolution coIP/MS workflow that works reliably in cultured cells (“SURE-ReCLIP”). Our technique does not require genetic manipulation or lysis/binding/wash condition optimization. We now want to expand the scope of the technique, and employ it to study protein-protein interactions in zebrafish embryos.

  • Proteolytic regulation of the nuclear pore complex

    Multiple eukaryotic and viral proteases (e.g., caspases, calpains, Polio/Rhino 2A, and Zika/Dengue NS3) target the subunits of the nuclear pore complex (NPC) during cell differentiation, stress, and infection. How does this affect nuclear transport and NPC-mediated genome folding? What makes the NPC a preferred target of so many proteases?