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Suckjoon Jun’s lab at UCSD

@junlab.bsky.social
464 followers 417 following 102 posts

We study quantitative microbial cell physiology. jun.ucsd.edu “If you want to go fast, go alone. If you want to go far, go together.” -African Proverb

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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 28/09/2026
5/5 We don’t yet know the mechanism. But the lesson is simple: a fluorescent reporter calibrated in one physiological condition cannot automatically be assumed quantitative in another. Preprint: www.biorxiv.org/content/10.6...
biorxiv.org
Fluorescent proteins misreport ribosome abundance under translation inhibition
Fluorescent proteins are widely used as quantitative reporters of protein abundance in living cells. Here we show that this relationship can break down under translation inhibition: the cellular ribos...
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 28/09/2026
4/5 A nice historical twist: the classic LacZ strategy from Rick Gourse’s lab still worked quantitatively at the ectopic rrnB promoter. Sometimes a biochemical reporter designed by the pioneers of the field survives a perturbation better than its fluorescent successor.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 28/09/2026
3/5 We built an mChartreuse–LacZ fusion so fluorescence and an independent abundance readout came from the same protein. Under translation inhibition, LacZ-derived abundance increased while fluorescence stayed ~constant: fluorescence per reporter molecule fell.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 28/09/2026
2/5 Under nutrient limitation, fluorescence tracked RNA/protein, a quantitative proxy for ribosome abundance, in both E. coli and B. subtilis. But with chloramphenicol, fluorescence stayed flat or fell even as ribosome abundance increased.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 28/09/2026
1/5 Do you use GFP to measure protein abundance? Be very careful. Our new bioRxiv preprint shows that, under translation inhibition, fluorescence can stop tracking how much reporter protein is actually there. Please share widely.
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Reyes-Lamothe lab @reyes-lab.bsky.social · 02/09/2026
We’re hiring! The Biology department at McGill is hiring a tenure-track professor in Quantitative Cell Biology. We’re looking for an outstanding researcher and educator to join our community. Deadline: October 9 Info & application: mcgill.wd3.myworkdayjobs.com/McGill_Caree... Please share!
mcgill.wd3.myworkdayjobs.com
Assistant Professor in Quantitative Cell Biology - Department of Biology
Please refer to the How to Apply for a Job (for External Candidates) job aid for instructions on how to apply. If you are an active McGill employee (ie: currently in an active contract or position at ...
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Mark Carney @mark-carney.bsky.social · 22/08/2026
We are masters in our own home.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 14/08/2026
Congratulations. As someone who’s spent a career doing science, it’s a strange feeling to think this policy may end up helping more people than anything I’ve done so far.
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Mayor Zohran Kwame Mamdani @mayor.nyc.gov · 13/08/2026
And this is just the beginning.
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Brian Stevenson Ph.D. spirochete lab @bstevensonlab.bsky.social · 04/08/2026
Remembering the life of Brandon Jutras gone far too soon www.nhscotthanekamp.com/obituaries/D...
nhscotthanekamp.com
Obituary information for Dr. Brandon Lyon Jutras
View Dr. Brandon Lyon Jutras's obituary, contribute to their memorial, see their funeral service details, and more.
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Angela Andersen @angelaandersen.bsky.social · 01/08/2026
Kudos to @science.org for this self-analysis of the peer review process. These kind of data are never shared and don't have to be. Wildly refreshing to see it out in the open. Editorial and peer review dynamics at elite general science journals | Science Advances www.science.org/doi/10.1126/...
science.org
Editorial and peer review dynamics at elite general science journals
Analyses of deidentified data reveal complex interactions that quantify success at elite general science journals.
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Paul Rainey @paulbrainey.bsky.social · 24/07/2026
Academic advice travels downhill: manage your supervisor, publish early, protect your time. Where is the genre in which early-career researchers advise the people who hire, fund and judge them? New post 👇 academicrenewal.substack.com/p/the-first-...
academicrenewal.substack.com
The first curriculum
Academic survival guides teach junior researchers how to live with the judgements of senior scholars. No corresponding genre gives young researchers authority to advise the people who judge them.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 13/07/2026
Arguably the most important installment in this series so far. Will resonate with many idealists who see academia clearly, yet remain committed to it. Perhaps will also help mentees glimpse the weight their mentors carry.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 08/07/2026
This is important.
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Loïc A. Royer 💻🔬🧪 @loicaroyer.bsky.social · 29/06/2026
1/ 🧬🔬 How does one cell become an entire animal? We can now film it in 3D 🐟, but turning those movies into accurate cell tracks is brutally hard. Enter our new #Kaggle challenge: $60K prize pool, to help crack 3D+time cell tracking at scale! 🧵👇 www.kaggle.com/competitions... @biohub.org
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 24/06/2026
17/ Above all, thank you William Irvine, Stefano Sacanna, Edo Kussell, and Hiro Funabiki (@hirofunabiki.bsky.social) for your friendship. We leave New York with this song, 糸/“Ito”, for all the people we met here. 縦の糸はあなた 横の糸は私 youtu.be/J3RWKacpfAA?...
youtu.be
Ito
YouTube video by Masaki Suda - Topic
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 24/06/2026
16/ Thank you, Michael Shelley, Yuhai Tu, and Indira Goris at CCB/Flatiron Institute, for your hospitality. Thank you also to the Simons Foundation for the Pivot Fellowship that made this year possible. And Stas Shvartsman, I may yet end up exploring the world of developmental biology after all. ;-)
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 24/06/2026
15/ Thank you, Alberto, for patiently teaching me economics and showing me how economists think about the world. I will cherish our weekly meetings for a long time and look forward to continuing our collaboration.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 24/06/2026
14/ The kiddo promised he would never do it again. I know better.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 24/06/2026
13/ One day, when one of our children got separated from us in the busy streets of Manhattan, two strangers approached us and volunteered to help search for him. Thank you to them, and thank you to the 911 operators for their infinite patience with me that day.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 24/06/2026
12/ But the best part of New York was the New Yorkers, and the friends we made here. You proved again and again that the stereotypes about you were wrong. You were kind. You had a great sense of humor. And you always stood up for our kids on the subway.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 24/06/2026
11/ Chelsea galleries, I am sorry we discovered you only in the last weeks of our stay. Thank you for leaving such lasting impressions before it was too late.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 24/06/2026
10/ And the American paintings in the museums. Thank you, Mr. Gene, if I remember your name correctly. Picking up the kids from school and going to the Whitney on Fridays to see Hopper and other favorite American paintings was one of the highlights of our year in New York.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 24/06/2026
9/ And subway posters. The mask on the gentleman was not our doing. :)
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 24/06/2026
8/ Of course, there was unforgettable street art and graffiti.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 24/06/2026
7/ And all the little bookstores. I did not expect to find a stack of 'On Writing' in such a tiny shop in the village, packed with New Yorkers.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 24/06/2026
6/ Speaking of music, our family was lucky to learn piano at the Greenwich School of Music. We will always remember the piano rooms filled with serene light, and the backyard surrounded by trees and birds.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 24/06/2026
5/ And the barbers of Manhattan: disciplined, precise, and among the hardest-working people I saw in the city. My hat is off to you.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 24/06/2026
4/ You gave us music everywhere: jazz musicians in Washington Square Park, chamber music in small rooms, and the New York Philharmonic at Lincoln Center. Thank you to the musicians of this city for reminding us that what drives a life is not money, but passion.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 24/06/2026
3/ You gave us four magnificent seasons. You showed our California-born children leaves turning color and real snow for the first time in their lives. They did not even seem to mind the brutal cold, even when it emptied the streets of New Yorkers.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 24/06/2026
2/ Our family arrived one year ago. Time flew by.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 24/06/2026
1/ Goodbye, New York. We are going to miss you.
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Paul Rainey @paulbrainey.bsky.social · 18/06/2026
Public money should not flow automatically to journals that fail to meet acceptable standards of editorial quality, transparency and accountability. In this post I ask what a journal accreditation system might look like & how it could work. academicrenewal.substack.com/p/building-a...
academicrenewal.substack.com
Building a journal accreditation system
How journals could be assessed without favouring size, wealth or brand
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 19/06/2026
let us know what you think!
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 18/06/2026
Guilty as charged 😀
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 18/06/2026
Thank you, Rodrigo!
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 18/06/2026
10/ A personal note: some of the work I'm proudest of came out in Current Biology, not Science. The mother machine, the adder, the mechanistic origin of the adder. Paper: www.science.org/doi/10.1126/.... I'd genuinely welcome disagreement.
science.org
Decoupling of global metabolic flux and proteome partitioning in bacteria
Bacteria regulate homeostatic growth by adjusting proteome composition. In Escherichia coli, this coordination is mediated by guanosine tetraphosphate and pentaphosphate, collectively termed (p)ppGpp,...
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 18/06/2026
9/ A decade-long project across three generations of PhD students who gave their 20s to it. Stuck on the mechanism, we turned to Jade Wang's lab, whose (p)ppGpp and GTP biology took it to a new level. The lesson I keep relearning: collaborate with friends, not business partners.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 18/06/2026
8/ In hindsight this isn't surprising. Ecology and evolutionary biology have long emphasized deep diversity across lineages. But the consequence is real: E. coli has been the default model for bacterial physiology. It's time to move beyond it if we want truly general principles.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 18/06/2026
7/ So the assumption that flux and proteome composition move together turns out to be one solution among several, not a law. How growth is controlled across much of bacterial diversity remains genuinely open.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 18/06/2026
6/ What makes this more than one bacterium is the phylogeny. Both lineages use (p)ppGpp, but not in the same way. The Proteobacterial solution, exemplified by E. coli, acts directly on RNA polymerase. In Firmicutes, the control we describe is routed through GTP instead.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 18/06/2026
5/ Why would a cell hold its growth below capacity? Because the setting that buys faster growth costs survival. GTP up: faster growth, dies under antibiotics. GTP down: slower growth, endures. Wild-type sits at a regulated balance. Growth and survival pull against each other.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 18/06/2026
4/ The result is a cell growing slower than the standard picture predicts. And the finding I keep coming back to: we could undo it. By tuning one internal signal, GTP, we restored fast, near-optimal growth under the antibiotic. The slow growth wasn't a trap. It was regulated.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 18/06/2026
3/ We tested whether it holds in Bacillus subtilis, which solves the same problem with different wiring. It doesn't, in an instructive way. Block translation and E. coli reorganizes its proteome to cope. B. subtilis barely moves its proteome but throttles amino acid synthesis.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 18/06/2026
2/ The premise of microbial physiology is simple. A bacterium grows as fast as it can by carefully dividing its protein budget between ribosomes and everything else. Built largely in E. coli, this logic has been remarkably successful.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 18/06/2026
1/ Out today in Science (@science.org): a result a decade in the making, and one that changed how I think about what cells are doing when they grow. We found a bacterium that grows slower than it could. And we found the molecular switch that lets us reverse it.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 15/06/2026
😂😂😂
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Paul Rainey @paulbrainey.bsky.social · 13/06/2026
Amongst it all: science is the most humanising of activities. It crosses boundaries, breaks boundaries & reminds that no matter our individual backgrounds or professions, we all delight in figuring out how things work. And fundamentally, we are all scientists: marvel at the curiosity of kids.
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Suckjoon Jun’s lab at UCSD @junlab.bsky.social · 09/06/2026
“…early-career researchers in particular need to survive in the system as it is now… speak more openly with them about the difference between scholarship & career strategy, helping them navigate [] realities /wo pretending that the system is healthy – or accepting that it cannot be made well again.“
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Paul Rainey @paulbrainey.bsky.social · 09/06/2026
Our piece about academic renewal is now out in the Times Higher Education. It deals with a familiar topic on which there have been multiple high-level declarations. We need to move beyond the symbolic. Early career researchers, pls read + ask questions! www.timeshighereducation.com/depth/academ...
timeshighereducation.com
Academic renewal needs pressure from below and responsibility from above
High-level declarations pledging not to misuse metrics in research assessment are important, but they are far from enough. Senior academics, in particular, must use their influence to ensure instituti...
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