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Reposted by Meghan Morrissey

Journal of Cell Biology @jcb.org · 5d

@kirstin-rollins.bsky.social, @mmorrissey.bsky.social et al show that #macrophages attack adherent cells using #trogocytosis instead of #phagocytosis. Reducing adhesion increased phagocytosis. Mitotic cells, which disassemble adhesions, are more vulnerable to phagocytosis rupress.org/jcb/article/...

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Reposted by Meghan Morrissey

Rockefeller University Press @rupress.org · 5d

#Macrophages are presumed to attack antibody-opsonized #cancer cells by #phagocytosis. In @jcb.org, @kirstin-rollins.bsky.social, @mmorrissey.bsky.social et al find that macrophages attack adherent cells using #trogocytosis, or cell nibbling, instead of phagocytosis. rupress.org/jcb/article/...

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Meghan Morrissey @mmorrissey.bsky.social · Jul 22

Cool paper, congratulations!

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Reposted by Meghan Morrissey

Alison Criss @alisoncrissuva.bsky.social · Feb 28

Excited by phagocyte biology? Still making summer conference plans? The Phagocytes GRC has an amazing lineup of invited speakers and many opportunities for talks from submitted abstracts. Apply soon for full consideration! www.grc.org/phagocytes-c...

2025 Phagocytes Conference GRC

The 2025 Gordon Research Conference on Phagocytes will be held in Waterville Valley, New Hampshire. Apply today to reserve your spot.

www.grc.org

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Meghan Morrissey @mmorrissey.bsky.social · Feb 25

🎉🎉🎉

Meghan Morrissey @mmorrissey.bsky.social · Feb 12

I have been trying to ID the direct targets of these phosphatases since I started studying CD47 as a postdoc, but before this had only managed to find downstream targets. I am THRILLED to have a more satisfying answer.

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Meghan Morrissey @mmorrissey.bsky.social · Feb 12

With these clues, Wyatt pinpointed a specific cytoskeletal regulator that is dephosphorylated by SHP-phosphatases bound to SIRPA (CD47 receptor)... Vav1, a Rac GEF! Hyperactivating Vav1 or Rac meant macrophages could phagocytose cancer cells with CD47.

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Meghan Morrissey @mmorrissey.bsky.social · Feb 12

If macrophages managed to eat a target, it was through a slower sinking phagocytosis...

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Meghan Morrissey @mmorrissey.bsky.social · Feb 12

But when we added CD47, this type of phagocytosis failed...see how the macrophage keeps trying to extend membrane but doesn't quite make it

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Meghan Morrissey @mmorrissey.bsky.social · Feb 12

Macrophages usually reach out to phagocytose IgG coated targets... see the cell extending membrane out and around the bead

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Meghan Morrissey @mmorrissey.bsky.social · Feb 12

Wyatt Miller's thesis project is on bioRxiv! We describe the signaling cascade that allows the 'Don't Eat Me' signal CD47 to inhibit phagocytosis. www.biorxiv.org/content/10.1...

CD47 prevents Rac-mediated phagocytosis through Vav1 dephosphorylation

CD47 is expressed by viable cells to protect against phagocytosis. CD47 is recognized by SIRPα, an inhibitory receptor expressed by macrophages and other myeloid cells. Activated SIRPα recruits SHP-1 ...

www.biorxiv.org

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Meghan Morrissey @mmorrissey.bsky.social · Feb 10

This supports the idea that target cell's biophysical properties regulate the decision to trogocytose instead of phagocytose, as Caitlin Cornell @fletcherlabucb.bsky.social proposed in their recent preprint: doi.org/10.1101/2024.12.02.626490

Target cell tension regulates macrophage trogocytosis

Macrophages are known to engulf small membrane fragments, or trogocytose, target cells and pathogens, rather than fully phagocytose them. However, little is known about what causes macrophages to choo...

doi.org

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Meghan Morrissey @mmorrissey.bsky.social · Feb 10

Excited to share @kirstin-rollins.bsky.social thesis project! 🥳Why do macrophages sometimes eat a whole cell, and sometimes just nibble off pieces? We found that if the target cell is stuck to a substrate or part of a 3D tissue, the macrophage nibbles instead of phagocytosing the whole cell.

bioRxiv Cell Biology @biorxiv-cellbio.bsky.social · Feb 8

Target cell adhesion limits macrophage phagocytosis and promotes trogocytosis https://www.biorxiv.org/content/10.1101/2025.02.06.636906v1

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Reposted by Meghan Morrissey

Sen. Adam Schiff @schiff.senate.gov · Feb 8

Trump & Musk are making massive cuts to the National Institutes of Health.

I know there is a lot going on right now, but this is one of worst things they have done so far, will affect cancer research and trials, the search for cures, innovation and competitiveness, our universities. Your lives.

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Meghan Morrissey @mmorrissey.bsky.social · Jan 30

Thank you!!

Meghan Morrissey @mmorrissey.bsky.social · Jan 28

Thank you! 😀

Meghan Morrissey @mmorrissey.bsky.social · Jan 28

Thank you! 😀

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Meghan Morrissey @mmorrissey.bsky.social · Jan 28

Extremely grateful to Damon Runyon for this funding, especially with todays news on NIH grants. See a green macrophage nibbling on a pink cancer cell 👇

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Reposted by Meghan Morrissey

Damon Runyon Cancer Research Foundation @damonrunyon.org · Jan 28

@mmorrissey.bsky.social is investigating how immune cells known as macrophages might be induced to “nibble” cancer cells to death through a process called trogocytosis.

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Reposted by Meghan Morrissey

Damon Runyon Cancer Research Foundation @damonrunyon.org · Jan 28

Congratulations to the recipients of the 2025 Damon Runyon-Rachleff Innovation Award! Five exceptional scientists received initial grants, and three previous awardees were given Stage 2 support to continue their critical work. Read more: www.damonrunyon.org/news/entries...

Damon Runyon Cancer Research Foundation awards $3.2M to innovative early-career scientists

www.damonrunyon.org

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Reposted by Meghan Morrissey

Journal of Cell Science @jcellsci.bsky.social · Jan 13

@annalisebond.bsky.social and @mmorrissey.bsky.social @ucsantabarbara.bsky.social review the biochemical and biophysical mechanisms that macrophages use to tune phagocytic appetite.
journals.biologists.com/jcs/article/...

Cartoon showing that phagocytic receptor availability can be modulated through multiple mechanisms. Receptor availability can be modulated by (A) transcriptional changes affecting receptor expression levels, (B) receptor internalization, which reduces available ligand-binding sites, (C) ectodomain shedding, which can cause sequestration of ligands away from signalling domains, (D) post-translational modifications, such as conformational changes that affect ligand binding affinities, and (E) glycosylation that can affect receptor or ligand accessibility.

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Reposted by Meghan Morrissey

Enfu Hui @enfuhui.bsky.social · Jan 4

Thrilled to share our @sciimmunology.bsky.social paper! We report that rodent PD-1 is weaker than human PD-1 (reduced ligand binding & signaling) & lacks a conserved vertebrate motif. Humanizing mouse PD-1 disrupts T cell anti-tumor responses, raising many questions. science.org/doi/10.1126/...

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Meghan Morrissey @mmorrissey.bsky.social · Jan 3

Author share link journals.biologists.com/jcs/article/...

Biochemical and biophysical mechanisms macrophages use to tune phagocytic appetite

Summary: Macrophages regulate their phagocytic appetite to rapidly clear pathogens and debris while minimizing damage to the surrounding tissue. We discuss the molecular toolkit for tuning macrophage ...

journals.biologists.com

Meghan Morrissey @mmorrissey.bsky.social · Jan 3

Macrophages need to adjust their appetite based on whats happening around them... but how to make a macrophage hungrier? Annalise Bond assembled a list of biophysical and biochemical parameters that can tune phagocytosis. @jcellsci.bsky.social @biologists.bsky.social

doi.org/10.1242/jcs....

Biochemical and biophysical mechanisms macrophages use to tune phagocytic appetite

Summary: Macrophages regulate their phagocytic appetite to rapidly clear pathogens and debris while minimizing damage to the surrounding tissue. We discuss the molecular toolkit for tuning macrophage ...

journals.biologists.com

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Meghan Morrissey @mmorrissey.bsky.social · Dec 15

At #Ascb? Check our Wyatt Millers poster on CD47 today at 1:30 (b696) or his talk Monday at 5:30 p in the immune cell biology subgroup!

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