John Burke

@jburkevic.bsky.social

Professor at the University of Victoria. Structural biologist studying phosphoinositides, membrane signalling, and nanobodies using HDX-MS, x-ray crystallography and cryo EM

Proud to share the yeast telomerase structure, led by the talented @hongmiaohu.bsky.social in collaboration with the Wellinger and Chartrand labs. Discovered 37 years ago and took us nearly 7 years but totally worth the wait 😍. www.science.org/doi/10.1126/... www.youtube.com/watch?v=gFE4...

Cryo-EM structure of yeast telomerase

YouTube video by MRC Laboratory of Molecular Biology

youtube.com

MRC Laboratory of Molecular Biology@mrclmb.ac.uk · 4mo ago

Led by Investigator Scientist @hongmiaohu.bsky.social, @kellythd-nguyen.bsky.social’s group in the LMB’s Structural Studies Division have produced the first ever structure of telomerase from yeast. Read more here: mrclmb.ac.uk/news-events/... #LMBResearch #cryoEM 🧪

Another interesting example of how cPLA2 senses nuclear deformation and controls immune cell behaviour. Since the enzyme adsorbs to hydrophobic lipid packing defects, membrane tension and high positive curvature can have similar effects as membrane tension. www.science.org/doi/10.1126/...

cPLA2α targeting to exosomes connects nuclear deformation to LTB4-signaling during neutrophil chemotaxis

Nuclear squeezing triggers lipid signals that help neutrophils stay on course through tight spaces.

science.org

Please spread the word: the Structural Studies Division @mrclmb.bsky.social is looking for a new tenure-track, independent group leader with an exciting plan in any area of Structural (Molecular & Cell) biology, in discovery biology and/or methods development. 🥳 mrc.tal.net/vx/mobile-0/...

Research Group Leader Tenure Track - Structural Studies - LMB 2775 - Medical Research Council

Location: Cambridge. Vacancy: Research Group Leader Tenure Track - Structural Studies - LMB 2775. Closing Date: 16/03/2026, 23:55

mrc.tal.net

Do you want to know more about how Retromer regulates Rab7 activity in yeast? Of course you do. Check out the new collaboration with Andreas Mayer with work led by Catarina Alves and Kevin Chen.

The GTPase activating protein Gyp6 binds Retromer and inactivates Rab7/Ypt7 to coordinate the formation of endosomal carriers

The Retromer coat is conserved in all eukaryotes and is crucial for the correct intracellular sorting of many transmembrane receptors and lysosomal hydrolases. Retromer is an effector of the late endosomal small GTPase RAB7 and is also implicated in its inactivation required for proper endosomal maturation. Here, we explore the role of controlled GTP hydrolysis by the RAB7 ortholog Ypt7 in the formation of Retromer-coated membrane carriers in yeast. Proximity labelling and genetic ablation identify the GTPase Activating Protein (GAP) Gyp6 as a critical regulator of Ypt7 activity in the context or Retromer. Structural studies show that Retromer recruits Gyp6 through its Vps29 subunit, which recognises a specific PL motif and a secondary binding site in the C-terminal domain of Gyp6. This interaction does not occur with other yeast GAPs. Ablation of the Gyp6-Retromer interface or the catalytic activity of Gyp6 leads to the accumulation of tubular structures on endo-lysosomal compartments and to increased association of Ypt7 with Retromer and its cargo Vps10. These results support a model in which Gyp6 controls the switch from Ypt7-dependent Retromer coat assembly and cargo collection to the departure of the carrier through membrane fission and uncoating. ### Competing Interest Statement The authors have declared no competing interest. National Health and Medical Research Council, https://ror.org/011kf5r70, APP2016410 Swiss National Science Foundation, https://ror.org/00yjd3n13, 31003A_179306, 310030_204713, 10.006.083

biorxiv.org

A while back we found that the lipid-binding protein PLEKHA4 boosts Wnt/β-catenin signaling and drives melanoma growth in vivo. Now, we (Nathan Frederick) identify small-molecule inhibitors of PLEKHA4 & related proteins with anticancer activity in vitro! pubs.acs.org/doi/10.1021/....

Discovery, Optimization, and Anticancer Activity of Lipid-Competitive Pleckstrin Homology Domain-Containing Family A Inhibitors

Phosphoinositide signaling is a major cellular mechanism controlling cancer cell viability, proliferation, and survival. Yet, inhibition of lipid kinases that produce oncogenic phosphoinositides has afforded only a limited number of efficacious drugs attributed in large part to on-target toxicity resulting from the pleiotropic effects of these signaling lipids. Targeting the specific phosphoinositide effector pathways via competitive inhibitors of phosphoinositide-recognizing pleckstrin homology (PH) domains represents a relatively unexplored means to achieve greater specificity. Herein, we present the discovery from in silico screening, structure–activity relationship (SAR) optimization, and cellular characterization of novel phosphoinositide-competitive inhibitors of the pleckstrin homology domain-containing A (PLEKHA) family. These compounds induce cytotoxic effects in BRAF and NRAS mutant melanoma cells, consistent with on-target inhibition, and the most potent compound is activated by endogenous esterase activity, suggesting that prodrug esters represent a viable strategy for targeting the phosphoinositide-binding pockets of the PLEKHA family of PH domains.

pubs.acs.org

Announcing our new PA biosensor, PILS-Nir1 – seen here in HeLa cells during PLC activation #lipidtime #phospholipids Read the OA paper in JCB

Rockefeller University Press@rupress.org · 11mo ago

In @jcb.org, @cwecks.bsky.social, Rahn, @gerryhammond.bsky.social et al. report a novel biosensor, PILS-Nir1, that detects phosphatidic acid in live cells, revealing the lipid’s dynamics with improved sensitivity and selectivity over existing probes. rupress.org/jcb/article/... #phospholipids

Have you published lipid-protein interactome data? Please let us know, we’d love to include it in the repository. The goal is to build a centralized hub for the scientific community. Huge thanks to Gaelen Guzman, a graduate student/postdoc in the lab who built it from scratch.

Bild
Jeremy Baskin@jeremybaskin.bsky.social · last yr.

We are proud to be a founding contributor to lipidinteractome.org, a repository developed by @tafesselab.bsky.social & Schultz lab to increase accessibility to proteomics data from multi-functionalized lipid analogs! Check out the website & preprint: arxiv.org/abs/2507.23101 #lipidtime