Dynamic, scaffolded, multi-protein complexes are hallmarks of sophisticated cellular signaling systems. The higher-order architecture of these signaling complexes confers sensitivity, adaptability, control, and crosstalk. Signaling complex architecture is especially notable in the nervous system, where dynamic post-synaptic protein assemblies underlie the molecular origins of learning and memory. Moreover, post-translational modifications within the signaling complexes induce conformational changes to modulate reorganization and retargeting. Understanding the dynamic architecture of these protein assemblies is crucial because disruptions in this system are implicated in neurological disorders such as Parkinson’s disease, autism spectrum disorders, depression, and schizophrenia.
Our lab employs mass spectrometry and chemical tools to probe the interactions and post-translational modifications that contribute to synaptic signaling strength and plasticity. Among these techniques, we use hydrogen-deuterium exchange mass spectrometry (HDX-MS) to map protein—protein interactions and conformational changes in dynamic signaling complexes. In addition, we employ diverse chemical tools for probing protein—protein interactions, such as crosslinkers, artificial amino acids, and spectroscopic tags. By integrating maps of protein interaction surfaces with the structures of the protein components, we can devise models of the higher-order architecture of the signaling assemblies. Furthermore, we can test how post-translational modifications and conformational changes remodel the architecture. Our targets of inquiry include kinases, trafficking chaperones, nitric oxide signaling components, and the scaffolding proteins that assemble these diverse signaling effectors together at the synaptic membrane.