protein interactions

HIV-1 Matrix and Envelope Protein Interactions

It is important to characterize how HIV-1 proteins fulfill their functions in order to develop new approaches for curtailing the AIDS epidemic. One of the remaining frontiers of HIV-1 research concerns the mechanisms by which the HIV-1 matrix (MA) and envelope (Env) proteins collaborate with each other to ensure the assembly of infectious viruses. The HIV-1 MA protein directs the delivery of precursor Gag (PrGag) proteins to the plasma membranes (PMs) of infected cells, and drives the formation of lipid raft-like, liquid ordered (Lo) membrane domains. This membrane reorganization attracts a number of proteins that favor lipid raft-type microdomains. Such proteins appear to assemble into virus particles as innocent bystanders, and this appears to be how Env proteins that carry cytoplasmic tail deletions (CT) can be incorporated into virions. In contrast, wild type (WT) Env proteins additionally require an interaction with MA proteins to assemble into viruses. This is most easily understood in the context of the lattice that MA proteins construct at the PMs of infected cells. In particular, multiple lines of evidence imply that the CTs of WT Env proteins are trapped by MA lattices in immature, assembling virus particles, and then are released after assembled viruses are processed into their mature forms. Despite a seeming consensus on the MA-Env interaction steps, there are a number of very significant unknowns. Using our recent and preliminary results as a foundation, and taking advantage of the unique expertise of our collaborators, we propose the characterization of WT and mutant MA lattices, and of interactions of MA and Env with each other, and with membrane lipids. Our results will help clarify how MA and Env cooperate; they will illuminate aspects of host cell protein-membrane interactions; and they will foster the development of new approaches to intefere with HIV-1 replication.

AI-guided structural biology of Cav1.2

Project Summary/Abstract The L-type calcium channel Cav1.2 plays a critical role in excitation-contraction coupling in the heart. Its calcium flux generates the plateau phase of the cardiac action potential and results in the calcium-induced calcium release needed to trigger cardiac contractions. Cav1.2 is a multi-subunit protein consisting of a large, transmembrane 1 subunit and smaller, auxiliary subunits important for trafficking and channel regulation. Recent cryogenic electron microscopy (cryo-EM) experiments have revealed much of the three-dimensional structure of Cav1.2’s core domains, though the final 571 residues of the 1 subunit’s intracellular C-terminal domain (CTD) have not yet been resolved despite key regulatory roles in channel function. This domain has been shown to be important for Cav1.2’s regulation by calcium/calmodulin and has an important role in cross- talk between Cav1.2 and the sympathetic nervous system, amongst other cell signaling pathways. In this proposal, I will use insights from artificial intelligence to develop a platform for CTD structural biology, then validate that platform by measuring its ability to form protein-protein interactions with known binding partners of Cav1.2, including calcium/calmodulin and an autoregulatory distal C-terminal fragment. If successful, I will also attempt crystallization of the CTD in complex with several binding partners. Together these data will provide the starting point for future structural biology projects on Cav1.2 regulation and protein-protein interactions.

The synaptic functions of Alpha Synuclein and Lrrk2

Alpha synuclein and Lrrk2 are key players in Parkinson's disease and related disorders, but their normal role has been confusing and controversial. Data from acute gene-editing based knockdown, followed by functional assays, will be presented.

Understanding the cellular and molecular landscape of autism spectrum disorders

Large genomic studies of individuals with autism spectrum disorders (ASD) have revealed approximately 100-200 high risk genes. However, whether these genes function in similar or different signaling networks in brain cells (neurons) remains poorly studied. We are using proteomic technology to build an ASD-associated signaling network map as a resource for the Autism research community. This resource can be used to study Autism risk genes and understand how pathways are convergent, and how patient mutations change the interaction profile. In this presentation, we will present how we developed a pipeline using neurons to build protein-protein interaction profiles. We detected previously unknown interactions between different ASD risk genes that have never been linked together before, and for some genes, we identified new signaling pathways that have not been previously reported. This resource will be available to the research community and will foster collaborations between ASD researchers to help accelerate therapeutics for ASD and related disorders.

Enhancing potassium-chloride co-transporter-2 (KCC2) function in neurons by targeting protein-protein interactions

Evaluation of synaptic connectivity and dysfunction in aging mouse brains using an RNAscope multiomic spatial imaging assay (MSIA) that detects RNA, proteins, and protein interactions

FENS Forum 2024