Luminal surface proteome of the brain vasculature uncovers blood-brain barrier regulators @ScienceMagazine: science.org/doi/10.1126/scie… Big thanks to Zijian, Zuzhi, Yupu, Khanh, Yuxiang, and all collaborators to make this possible!

APEX peroxidase is a versatile tool for proximity labeling and electron microscopy (EM) but its requirement for toxic H2O2 is a liability. We now report LaccID, a multicopper oxidase evolved from an ancestral fungal laccase that oxidizes aromatic substrates using non-toxic O2 instead of H2O2. We use LaccID for EM imaging of cultured cells and fly brains, and for proteomic mapping of the changing surface composition of T cells that engage with tumor cells via antigen-specific T cell receptors.

Glad to share our latest study on the cell-surface proteome of human dendritic cells, by our awesome long-term collaborators Namrata and Charles @BroadProteomics and talented undergrad @Zuzhi_Jiang (soon at @UCSF tetrad for PhD). journals.aai.org/jimmunol/ar…

TransitID is out today in Cell! This is a proximity labeling method for unbiased discovery of endogenous proteins that traffick from a defined “source” location to a defined “destination” location. TransitID uses sequential labeling by TurboID in the source, followed by a chase period (minutes to hours) and then 1-minute APEX tagging in the destination compartment. Proteins tagged by both enzymes are enriched with streptavidin and anti-fluorescein antibody, and identified by mass spec. We explore 4 intracellular and intercellular applications of TransitID: - discovery of locally translated mitochondrial proteins (translated at OMM, then imported into mito matrix) - mapping proteins whose cytoplasm-to-nucleus shuttling is dampened by stress - discovery of proteins that transit between nucleolus & stress granules during stress & stress recovery - analysis of proteins that traffic intercellularly bw tumor cells & macrophages Work of amazingly talented co-first authors @WeiQinChemBio and @CheahJoleen, and collaborators Steve Carr @namude & Paul Taylor authors.elsevier.com/a/1hKLc…

Very good 😃DIA MS session at #ASMS2023 Thanks to all the great speakers.

If you’re at #ASMS2033 this week come check out these talks and posters by members of the Broad Proteomics Team!!

Light-regulated TurboID, or LOV-Turbo, is a feat of engineered allostery, created by @SongyiLee10 and @CheahJoleen via structure-guided design, then optimized by yeast display directed evolution. Activity is nearly undetectable in the dark state, but increases within seconds to a level comparable to TurboID after weak blue-light illumination. Removing light shuts LOV-Turbo off again (ie, it is reversible). LOV-Turbo is easy to use in mammalian cells, yeast, bacteria, and even in the mouse brain to suppress background labeling from endogenous biotin, to perform pulse-chase proteomics, and to spatially control biotinylation. We also show that instead of external blue light, LOV-Turbo can be activated by genetically-encoded light, ie bioluminescence from luciferase, via BRET (Figure 4F-I). Huge thanks to incredibly talented co-first authors @SongyiLee10 and @CheahJoleen, and our wonderful collaborators Steve Carr and @namude. Also many thanks to co-authors @Simenzhao, Charles Wu, @heegwangroh, @tinakim_neuro and @kelvinfcho for their contributions. Plasmids will be available on Addgene in the near future! biorxiv.org/cgi/content/shor…

Do you want to get as much data as possible out of your limited tumor samples? Well now you can with our MONTE workflow! Our manuscript describing the serial enrichment of immunopeptidome, ubiquitylome, proteome, phosphoproteome and acetylome is out now! nature.com/articles/s41467-0…