Browsing by Subject "Allosteric regulation"

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    Experimental Evidence for Phosphorylation-Driven Allosteric Regulation of Alpha Synuclein Function
    (bioRxiv, 2025-02-26) Dollar, Ashlyn N.; Webb, Ian K.; Chemistry and Chemical Biology, School of Science
    Phosphorylation of serine 129 (pS129) in the intrinsically disordered protein alpha synuclein has long been associated with neurodegenerative disease. In the past several years, the functional relevance of pS219 has been uncovered by electrophysiology, immunoprecipitation, and proteomics as intricately connected with neurotransmitter release and synaptic vesicle (SV) cycling. Unexpectedly, binding to SNARE complex proteins VAMP-2 and synapsin only occurs with phosphorylation-competent alpha synuclein. The VAMP-2 binding domain has been shown to be residues 96-110, which does not include the phosphorylated residue, hinting at allosteric regulation of alpha synuclein protein-protein interactions by pS129. Within this study, cross-linking, covalent labeling, and collision induced unfolding of alpha synuclein and pS129 - as well as an additional encountered form in the brain, oxidized-M1, M5, M116, M127 alpha synuclein - are studied utilizing tandem mass spectrometry. Collision induced unfolding of proteins gives a fingerprint of the structures' relative compactness and stabilities of various conformations. Covalent labeling of proteins identifies solvent accessible residues and reveals the hydrophobicity (or hydrophilicity) of their microenvironment, while cross-linking of proteins maps the proximity of residue pairs. The combination of collision induced unfolding, covalent labeling, and cross-linking show unequivocally that phosphorylated-S129 alpha synuclein results in a more stable, more compact form. Our results provide evidence of an extensively folded amphipathic region that interacts strongly with the VAMP-2 binding domain. The phosphorylation-induced folding of the amphipathic region likely tunes other protein-protein interactions and interactions with SVs and membranes.
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    Roc, the G-domain of the Parkinson’s disease-associated protein LRRK2
    (Elsevier, 2022) Park, Yangshin; Liao, Jingling; Hoang, Quyen Q.; Biochemistry and Molecular Biology, School of Medicine
    Mutation in LRRK2 (Leucine-rich repeat kinase 2) is a common cause of Parkinson’s disease. Aberrant LRRK2 kinase activity is associated with disease pathogenesis, and thus it is an attractive drug target for combating PD. Intense efforts in the past nearly two decades have focused on developing small-molecule inhibitors of the kinase domain of LRRK2, which have identified potent kinase inhibitors. However, most LRRK2 kinase inhibitors have shown adverse effects; therefore, alternative mechanism-based strategies are desperately needed. In this review, we will discuss the new insights gleaned from recent cryo-EM structures of LRRK2 towards understanding the mechanisms of actions of LRRK2 and explore the potential new therapeutic avenues.