Biology subjects

McCormick, P.

Publications and source records attributed to McCormick, P..

4 recordsLinked to original sources

bioRxiv2024

MRAP2 modifies signaling and oligomerization state of the melanocortin-4 receptor

The melanocortin-4 receptor (MC4R) is a G protein-coupled receptor (GPCR) and a key regulator of appetite and metabolism. It can interact with the melanocortin-receptor accessory protein 2 (MRAP2), a single transmembrane helix protein known to interact with several different GPCRs. However, the consequences of this interaction are not completely understood. Here we report that co-expression of MRAP2 has multiple effects on the MC4R: it enhances G protein-mediated signaling and simultaneously impairs {beta}-arrestin2 recruitment and, consequently, internalization. In addition, co-expression of MRAP2 leads to an increased number of monomers of MC4R by disrupting receptor oligomers. A structural homology model of the active state MC4R-MRAP2-Gs complex suggests interaction sites between MRAP2 and MC4R that are relevant for receptor activation. Taken together, our data indicate that MRAP2 is an accessory protein that interacts with and influences MC4R structure, biasing its signaling towards G protein-mediated effects.

pharmacology and toxicology↗

bioRxiv2022

The Batten disease protein CLN3 is important for stress granules dynamics and translational activity.

The assembly of membrane-less organelles such as stress granules (SGs) is emerging as central in helping cells rapidly respond and adapt to stress. Following stress sensing, the resulting global translational shutoff leads to the condensation of stalled mRNAs and proteins into SGs. By reorganising cytoplasmic contents, SGs can modulate RNA translation, biochemical reactions and signalling cascades to promote survival until the stress is resolved. While mechanisms for SG disassembly are not widely understood, the resolution of SGs is important for maintaining cell viability and protein homeostasis. Mutations that lead to persistent of aberrant SGs are increasingly associated with neuropathology and a hallmark of several neurodegenerative diseases. Mutations in CLN3 are causative of juvenile neuronal ceroid lipofuscinosis (JNCL), a rare neurodegenerative disease affecting children. CLN3 encodes a transmembrane lysosomal protein implicated in autophagy, endosomal trafficking, metabolism, and response to oxidative stress. Using a HeLa KO model, we now show that CLN3KO is associated with an altered metabolic profile, reduced global translation, and altered stress signalling. We further demonstrate that loss of CLN3 results in perturbations in SG dynamics, resulting in assembly and disassembly defects, and altered expression of the key SG nucleating factor G3BP1. With a growing interest in SG-modulating drugs for the treatment of neurodegenerative diseases, novel insights into the molecular basis of CLN3 Batten disease may reveal avenues for disease-modifying treatments for this debilitating childhood disease.

molecular biology↗

bioRxiv2021

Structural basis of main proteases of coronavirus bound to drug candidate PF-07321332

The high mutation rate of COVID-19 and the prevalence of multiple variants strongly support the need for pharmacological options to complement vaccine strategies. One region that appears highly conserved among different genus of coronaviruses is the substrate binding site of the main protease (Mpro or 3CLpro), making it an attractive target for the development of broad-spectrum drugs for multiple coronaviruses. PF-07321332 developed by Pfizer is the first orally administered inhibitor targeting the main protease of SARS-CoV-2, which also has shown potency against other coronaviruses. Here we report three crystal structures of main protease of SARS-CoV-2, SARS-CoV and MERS-CoV bound to the inhibitor PF-07321332. The structures reveal a ligand-binding site that is conserved among SARS-CoV-2, SARS-CoV and MERS-CoV, providing insights into the mechanism of inhibition of viral replication. The long and narrow cavity in the cleft between domains I and II of main protease harbors multiple inhibitor binding sites, where PF-07321332 occupies subsites S1, S2 and S4 and appears more restricted compared with other inhibitors. A detailed analysis of these structures illuminated key structural determinants essential for inhibition and elucidated the binding mode of action of main proteases from different coronaviruses. Given the importance of main protease for the treatment of SARS-CoV-2 infection, insights derived from this study should accelerate the design of safer and more effective antivirals.

biophysics↗

bioRxiv2019

Modulation of dopamine D1 receptors via histamine H3 receptors is a novel therapeutic target for Huntington’s disease

Early Huntingtons disease (HD) include over-activation of dopamine D1 receptors (D1R), producing an imbalance in dopaminergic neurotransmission and cell death. To reduce D1R over-activation, we present a strategy based on targeting complexes of D1R and histamine H3 receptors (H3R). Using an HD striatal cell model and HD organotypic brain slices we found that D1R-induced cell death signaling and neuronal degeneration, are mitigated by an H3R antagonist. We demonstrate that the D1R-H3R heteromer is expressed in HD animal models at early but not late stages of HD, correlating with HD progression. In accordance, we found this target expressed in human control subjects and low-grade HD patients. Finally, treatment of HD mice with an H3R antagonist prevented cognitive and motor learning deficits, as well as the loss of heteromer expression. Taken together, our results indicate that D1R - H3R heteromers play a pivotal role in dopamine signaling and represent novel targets for treating HD.\n\nImpact StatementProgression of Huntingtons disease can be slowed by altering dopamine signalling through the Dopamine 1 receptor - Histamine 3 receptor heteromer.

neuroscience↗