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Biology subjects

Boatner, L.

Publications and source records attributed to Boatner, L..

4 recordsLinked to original sources

Acetylated PLIN2 coordinates the innate immune system and oxylipin synthesis on lipid droplets to propagate inflammation

Research has implicated lipid droplets (LDs) and their associated proteins in inflammation and the innate immune response. The key LD protein Perilipin 2 (PLIN2) is tightly correlated with lipid storage and inflammation, but little is known about the mechanisms underlying its proinflammatory effects. Here, we show that PLIN2 is required for the inflammatory response to mitogens and the recruitment of pro-inflammatory proteins to the surface of LDs. PLIN2 directly binds arachidonic acid and interacts with key oxylipin synthetic enzymes such as PLA2 and COX2 to promote LD-localized oxylipin synthesis and propagate inflammatory signaling. Moreover, LPS induces PLIN2 hyperacetylation, and acetylation-dead PLIN2 mutants lose their proinflammatory properties in the presence of an inflammatory stimulus, as if PLIN2 were ablated. Thus, acetylated PLIN2 forms a key metabolon on LDs that is essential for the response and amplification of proinflammatory signaling.

immunology↗

Endocrine-metabolic decoupling drives stress vulnerability in dystrophin deficiency

Skeletal muscle orchestrates systemic metabolism, dynamically coordinating glucose uptake and fuel use to match energy demand. In Duchenne muscular dystrophy, loss of dystrophin is associated with altered metabolic regulation. In the mdx mouse, we show that physiological stress reveals impaired coordination between insulin and stress responses: glucocorticoid signalling increases without a proportional rise in insulin secretion, resulting in systemic hyperglycaemia despite preserved capacity for muscle glucose uptake. These data support a multi-tissue dystrophinopathy associated with altered endocrine-metabolic coordination. Skeletal muscle glycogen is elevated and incompletely mobilised under stress. The heart maintains high glucose uptake, whereas the brain exhibits reduced uptake, highlighting tissue specific differences in metabolic response. Acute insulin supplementation improves systemic glucose control and restores stress-induced behavioural deficits. Likewise, empagliflozin-mediated glucose offloading reduces stress-associated blood glucose spikes and is associated with improved muscle function to levels comparable with standard care prednisolone. These findings identify impaired coordination of endocrine and metabolic responses during stress as a contributor to metabolic vulnerability in DMD and suggest that modulating insulin availability or glucose flux can improve systemic metabolic control.

systems biology↗

A Scalable Design for Proximity-Inducing Molecules

Chimeric molecules, which bring together an effector enzyme and a protein-of-interest (POI) to add/remove post-translational modifications (PTMs), are furnishing transformative modalities (e.g., PROTACs). However, these chimeras scalability is limited as they employ rare, non-inhibitory binders of effectors. We report GRoup-transfer chimeras for Inducing Proximity (GRIPs) that employ abundantly available effectors inhibitors to append POI binder on the effector using group-transfer handles. To demonstrate scalability, we develop 6 GRIPs classes for 3 PTMs utilizing diverse inhibitor, spanning 16 effector-POI pairs. Furthermore, we report a toolbox of 42 tunable group-transfer handles for Cys/Lys residues and [~]5000 inhibitor-residue pairs for diverse effectors. Using global proteomics, we confirm the specificity for group transfer and PTM editing. GRIPs endowed new functionalities to POI drugs, including preventing rebound signaling upon drug withdrawal, a more potent/persistent inhibition, and inhibitor-induced pathway activation in 4 fully-endogenous systems. In diverse hemi-endogenous systems (tagged POI), GRIPs induced condensate formation with reduced off-targets, cleared pathogenic PTMs, and initiated PTM crosstalk. Overall, GRIPs provide a scalable and versatile platform for PTM editing. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=184 SRC="FIGDIR/small/706349v1_ufig1.gif" ALT="Figure 1"> View larger version (41K): org.highwire.dtl.DTLVardef@132f70dorg.highwire.dtl.DTLVardef@f9aa62org.highwire.dtl.DTLVardef@12143edorg.highwire.dtl.DTLVardef@f296d4_HPS_FORMAT_FIGEXP M_FIG C_FIG

synthetic biology↗

Defining the Cell Surface Cysteinome using Two-step Enrichment Proteomics

The plasma membrane proteome is a rich resource of functional and therapeutically relevant protein targets. Distinguished by high hydrophobicity, heavy glycosylation, disulfide-rich sequences, and low overall abundance, the cell surface proteome remains undersampled in established proteomic pipelines, including our own cysteine chemoproteomics platforms. Here we paired cell surface glycoprotein capture with cysteine chemoproteomics to establish a two-stage enrichment method that enables chemoproteomic profiling of cell Surface Cysteinome. Our "Cys-Surf" platform captures >2,800 total membrane protein cysteines in 1,046 proteins, including 1,907 residues not previously captured by bulk proteomic analysis. By pairing Cys-Surf with an isotopic chemoproteomic readout, we uncovered 821 total ligandable cysteines, including known and novel sites. Cys-Surf also robustly delineates redox-sensitive cysteines, including cysteines prone to activation-dependent changes to cysteine oxidation state and residues sensitive to addition of exogenous reductants. Exemplifying the capacity of Cys-Surf to delineate functionally important cysteines, we identified a redox sensitive cysteine in the low-density lipoprotein receptor (LDLR) that impacts both the protein localization and uptake of LDL particles. Taken together, the Cys-Surf platform, distinguished by its two-stage enrichment paradigm, represents a tailored approach to delineate the functional and therapeutic potential of the plasma membrane cysteinome.

biochemistry↗