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Robert Arkowitz

@robertarkowitz.bsky.social

Fascinated by fungal growth & asymmetries. Institute of Biology Valrose, CNRS-Inserm-Université Côté d’Azur, Nice. Microscopy addict, all things cell biological

4,283 Followers  |  3,985 Following  |  484 Posts  |  Joined: 11.11.2024  |  1.8976

Latest posts by robertarkowitz.bsky.social on Bluesky

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Butyrolactol A enhances caspofungin efficacy via flippase inhibition in drug-resistant fungi Chen et al. identify the natural product butyrolactol A as an inhibitor of the phospholipid flippase Apt1-Cdc50, which it locks in a nonfunctional state. By disrupting membrane homeostasis and enhanci...

www.cell.com/cell/abstrac...

07.02.2026 18:00 — 👍 5    🔁 0    💬 0    📌 0
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Synergistic interactions between Candida albicans and Enterococcus faecalis promote toxin-dependent host cell damage | PNAS The fungus Candida albicans and the Gram-positive bacterium Enterococcus faecalis share mucosal niches in the human body. As opportunistic pathogen...

www.pnas.org/doi/10.1073/...

06.02.2026 21:23 — 👍 5    🔁 0    💬 0    📌 0

And this work was done together with Niko Grigorieff, also MRC LMB alumni!

06.02.2026 18:13 — 👍 0    🔁 0    💬 0    📌 0
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Decreased cytoplasmic crowding via inhibition of ribosome biogenesis can trigger Candida albicans filamentous growth Nature Microbiology - During filamentous growth in the human fungal pathogen Candida albicans, a reduction in ribosome concentration leads to a decrease in macromolecular crowding. Inhibition of...

Thanks! I assume you are referring to this link, hope it works:

www.nature.com/articles/s41...

06.02.2026 18:10 — 👍 0    🔁 0    💬 1    📌 0
Stabilized real-time Brillouin microscopy reveals fractal organization of protein condensates in living cells - Nature Communications Testi and colleagues introduce an enhanced Brillouin Microscope for user-independent and high-precision mechanical measurements. Using this approach, the authors obtained insight into the biophysical ...

www.nature.com/articles/s41...

06.02.2026 14:42 — 👍 1    🔁 2    💬 0    📌 0
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Fungal infection drives metabolic reprogramming in epithelial cells via aerobic glycolysis and an alternative TCA cycle shunt Candida hijacks epithelial metabolism via glycolysis and GOT1-dependent TCA shunt, influencing antifungal defense.

www.science.org/doi/full/10....

06.02.2026 14:16 — 👍 4    🔁 4    💬 0    📌 0
Top: FK506-resistant strains isolated from the Mucor circinelloides complex. Phenotypic analysis of FK506-resistant isolates in Mucor janssenii CBS185.68 (PS1), Mucor bainieri CBS293.63 (PS3), and Mucor atramentarius CBS202.28 (PS6). WT, wild-type; M, mendelian mutant; E, epimutant. Bottom: Schematic overview of epigenetic silencing contributing to antifungal resistance in Mucor species. fkbA expression enables FKBP12 production and FK506 sensitivity (yeast-like morphology). Epigenetic silencing of fkbA via RNAi and/or heterochromatin leads to FK506 resistance and hyphal growth. Generated with BioRender.com.

Top: FK506-resistant strains isolated from the Mucor circinelloides complex. Phenotypic analysis of FK506-resistant isolates in Mucor janssenii CBS185.68 (PS1), Mucor bainieri CBS293.63 (PS3), and Mucor atramentarius CBS202.28 (PS6). WT, wild-type; M, mendelian mutant; E, epimutant. Bottom: Schematic overview of epigenetic silencing contributing to antifungal resistance in Mucor species. fkbA expression enables FKBP12 production and FK506 sensitivity (yeast-like morphology). Epigenetic silencing of fkbA via RNAi and/or heterochromatin leads to FK506 resistance and hyphal growth. Generated with BioRender.com.

#Antifungal resistance is a global threat, but epigenetic mechanisms drive rapid, reversible adaptation in fungi. This study shows that #RNAi or #heterochromatin driven #epimutations transiently silence the gene fkbA to confer FK506 #tacrolimus resistance in #Mucor @plosbiology.org 🧪 plos.io/4qdttWc

03.02.2026 14:00 — 👍 11    🔁 8    💬 0    📌 1
Top: Subcellular localization of Cap1-GFP in wild-type background (top, tetO-CAP1-GFP/CAP1), Cap1-GFP with C446* (middle, TeO-CAP1C446*-GFP/CAP1) and wild-type Cap1-RFP (bottom, CAP1C446*/TeO-CAP1-RFP) in CAP1/CAP1C446* background. Scale bar, 5 μm. Bottom: Schematic of subcellular localization and transcription activation of CAP1 in wild-type (CAP1/CAP1, left) and CAP1/CAP1C446*. Figure generated with BioRender.

Top: Subcellular localization of Cap1-GFP in wild-type background (top, tetO-CAP1-GFP/CAP1), Cap1-GFP with C446* (middle, TeO-CAP1C446*-GFP/CAP1) and wild-type Cap1-RFP (bottom, CAP1C446*/TeO-CAP1-RFP) in CAP1/CAP1C446* background. Scale bar, 5 μm. Bottom: Schematic of subcellular localization and transcription activation of CAP1 in wild-type (CAP1/CAP1, left) and CAP1/CAP1C446*. Figure generated with BioRender.

#Azole resistance in #Candida albicans poses a growing threat, and is linked to #StressResponse. @annaselmecki.bsky.social &co show that mutations in the oxidative stress TF Cap1 promote #DrugResistance while exposing a lethal vulnerability at high azole doses @plosbiology.org 🧪 plos.io/4rOrfOz

03.02.2026 17:40 — 👍 15    🔁 6    💬 0    📌 0
Trump slump? Attendance plummets at some science meetings, but others hold steady Amid travel bans, a government shutdown, and funding crunches, 2025 was a turbulent year for U.S. scientific societies

Amid travel bans, a government shutdown, and funding crunches, 2025 was a turbulent year for U.S. scientific societies. https://scim.ag/4c0ZWM4

03.02.2026 17:45 — 👍 15    🔁 4    💬 0    📌 0
A Genome-wide Visual Screen Identifies Lysophosphatidylcholine as Counter Spatial Regulator of DAG and Sterols in Yeast Membrane lipids are heterogeneously distributed across the bilayers of cellular membranes. Cytosolic-facing pools of diacylglycerol (DAG) in the yeast Saccharomyces cerevisiae are enriched at both ends of the endomembrane system from the vacuolar membrane to the polarized plasma membrane (PM) of buds. However, how this distribution is maintained remains unknown. Using a genome-wide DAG biosensor screen in yeast, we identify regulators of DAG spatial distribution, enriched in proteins involved in vesicle or lipid transport and in phospholipid or sterol metabolism. A subset of mutants exhibited DAG mislocalization predominantly to the PM, with the most severe phenotype linked to a mutant of a predicted lipase we have named Drl1 (DAG redistribution lipase 1). Reversion of this phenotype required both enzymatic activity and the presence of an intrinsically disordered carboxy-terminal domain. Lipidomic analysis revealed that loss of Drl1 increased cellular lysophosphatidylcholine (LysoPC) levels. Remarkably, we find that supplementing cells with a non-metabolizable LysoPC analogue replicated the mutant DAG phenotype, implicating LysoPC as a novel spatial regulator of DAG. High-resolution imaging suggests that LysoPC reduces the PM sterol pool resulting in DAG expansion into new PM territories. More globally, our work expands the known interplay between various lipids and their co-regulation to maintain accurate membrane properties. ### Competing Interest Statement The authors have declared no competing interest. Natural Sciences and Engineering Research Council, https://ror.org/01h531d29, 2023-04320 Alberta Innovates, AI 242506270 Canadian Institutes of Health Research, https://ror.org/01gavpb45, MOP-142403 Universidad de la Ciudad de Buenos Aires, UBACYT 20020190100122BA Chan Zuckerberg Initiative (United States), 2023-331952 Weizmann Institute of Science, https://ror.org/0316ej306

www.biorxiv.org/content/10.6...

31.01.2026 21:30 — 👍 1    🔁 0    💬 0    📌 0
This line graph illustrates the percentage change in agency staff levels from the previous year for nine major U.S. federal scientific and health organizations between the fiscal years 2016 and 2025. The agencies tracked include the CDC, Department of Energy, EPA, FDA, NASA, NIH, NIST, NOAA, and NSF. For the majority of the timeline between 2016 and 2023, the agencies show relatively stable fluctuations, generally staying within a range of +5% to -5% change per year. However, there is a dramatic and uniform plummet starting in the 2024–25 period. Every agency depicted shows a sharp downward trajectory, with staffing losses ranging from approximately -15% to over -25%. The Environmental Protection Agency (EPA) shows the most significant decline, dropping to roughly -26%, while the National Institute of Standards and Technology (NIST) shows the least severe but still substantial drop at approximately -15%.

This line graph illustrates the percentage change in agency staff levels from the previous year for nine major U.S. federal scientific and health organizations between the fiscal years 2016 and 2025. The agencies tracked include the CDC, Department of Energy, EPA, FDA, NASA, NIH, NIST, NOAA, and NSF. For the majority of the timeline between 2016 and 2023, the agencies show relatively stable fluctuations, generally staying within a range of +5% to -5% change per year. However, there is a dramatic and uniform plummet starting in the 2024–25 period. Every agency depicted shows a sharp downward trajectory, with staffing losses ranging from approximately -15% to over -25%. The Environmental Protection Agency (EPA) shows the most significant decline, dropping to roughly -26%, while the National Institute of Standards and Technology (NIST) shows the least severe but still substantial drop at approximately -15%.

This is the most astonishing graph of what the Trump regime has done to US science. They have destroyed the federal science workforce across the board. The negative impacts on Americans will be felt for generations, and the US might never be the same again.

www.nature.com/immersive/d4...

20.01.2026 22:53 — 👍 14465    🔁 8342    💬 91    📌 769
Dear Director Bhattacharya: I learned that Max Kozlov from Nature and Jocelyn Kaiser from Science (and perhaps others) were denied admission to today's "Reclaiming Science" MAHA Institute event. I call on you to issue a public statement condemning this outrageous act of suppression of fully credentialed members of the press. I would hope that you would feel compelled to do this as someone who claims to believe in freedom of expression and as a senior official of the United States government who swore an oath to our Constitution. Sincerely yours, Jeremy M. Berg United States citizen

Dear Director Bhattacharya: I learned that Max Kozlov from Nature and Jocelyn Kaiser from Science (and perhaps others) were denied admission to today's "Reclaiming Science" MAHA Institute event. I call on you to issue a public statement condemning this outrageous act of suppression of fully credentialed members of the press. I would hope that you would feel compelled to do this as someone who claims to believe in freedom of expression and as a senior official of the United States government who swore an oath to our Constitution. Sincerely yours, Jeremy M. Berg United States citizen

@maxkozlov.bsky.social @jocelynkaiser.bsky.social

I just sent this to Director Bhattacharya.

Let me know if you think of anything else I can do to help.

30.01.2026 20:23 — 👍 56    🔁 20    💬 2    📌 0
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Metabolically regulated proteasome supramolecular organization in situ Structural steps along the assembly of proteasome storage granules—membraneless organelles that form in response to metabolic shifts in yeast—are visualized inside cells by cryo-electron tomography. I...

www.cell.com/cell/fulltex...

29.01.2026 07:06 — 👍 2    🔁 1    💬 0    📌 0
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Check out our new paper in @natcomms.nature.com .com where we used #cryoEM together with biochemical and mutational analyses investigated the cotranslational protein folding by Ssb in yeast.

Publication: doi.org/10.1038/s41467-025-67685-6

Check below for the cryoEM centric feed. 👇

27.01.2026 14:57 — 👍 29    🔁 10    💬 1    📌 0
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American biomedical science in 2026 Where we are, how we got here, and what to do next

New at Can We Still Govern: NIH scientist @markhisted.org reviews the damage done to American biomedical science in the last year and looks ahead:
"Scientists should not be political partisans, but they should be partisans for liberal democratic principles."🧵
donmoynihan.substack.com/p/american-b...

27.01.2026 14:12 — 👍 324    🔁 124    💬 3    📌 15
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U.S. government has lost more than 10,000 STEM Ph.D.s since Trump took office A Science analysis reveals how many were fired, retired, or quit across 14 agencies

America is bleeding scientific talent

U.S. government has lost more than 10,000 STEM Ph.D.s since Trump took office | Science | AAAS www.science.org/content/arti...

27.01.2026 07:56 — 👍 73    🔁 49    💬 2    📌 4
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Latest work from the lab by Aude Nommick et al., in which we propose a "size-scaling" model for microtubule force exertion that regulates centrosome centration vs decentration during embryo development!
@ijmonod.bsky.social

www.biorxiv.org/content/10.6...

26.01.2026 15:45 — 👍 82    🔁 28    💬 0    📌 1
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A comprehensive view on r-protein binding and rRNA domain structuring during early eukaryotic ribosome formation Abstract. Formation of the eukaryotic ribosomal subunits follows a strict regime to assemble ribosomal proteins (r-protein) with ribosomal RNAs (rRNA) whil

And the 4th paper in this week contribution from our lab tells about ribosome biogenesis in yeast. A follow-up story from our wonderful collaborators in Graz - the Bergler Lab. Structural work was again done by the amazing @lgrundmann.bsky.social: academic.oup.com/nar/article/...

22.01.2026 17:27 — 👍 23    🔁 11    💬 1    📌 0
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Dozens Are Sickened by a Rare Fungal Infection in Tennessee

www.nytimes.com/2026/01/21/u...

23.01.2026 08:33 — 👍 1    🔁 0    💬 0    📌 0
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What is histoplasmosis? Outbreak leaves 1 dead, dozens ill in Tennessee Tennessee health officials are investigating a fungal infection outbreak that has killed at least one person and sickened dozens more.

www.livenowfox.com/news/what-is...

22.01.2026 09:01 — 👍 7    🔁 4    💬 0    📌 1
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‘Remote controlled’ proteins illuminate living cells The discovery that some fluorescent proteins are sensitive to magnets could lead to the development of switchable drugs and biosensors.

Researchers have engineered magnetically controlled fluorescent proteins that can be remotely dimmed and brightened in cells and living animals

go.nature.com/3NUSY12

21.01.2026 17:46 — 👍 56    🔁 22    💬 4    📌 1
Molecular Crowding-Driven Nucleosome Interactions Revealed Through Single-Molecule Optical Tweezers Molecular crowding causes the compaction of chromatin fibers, contributing to the formation of the nuclear architecture. However, the molecular mechanism of compaction under crowded conditions is not yet fully understood. In this study, we employed the single-molecule optical tweezer method to investigate the effect of molecular crowding on chromatin structure. Force-extension experiments on a 12-mer polynucleosome in the presence of different sizes and concentrations of polyethylene glycol (PEG) as a crowding agent showed that at low concentrations of low-molecular-weight (MW) PEG, the compaction of the polynucleosome was not significant. In this respect, nucleosomes predominantly remained separated, while DNA-histone interactions within individual nucleosomes were slightly stabilized. In contrast, high concentrations of high-MW PEG significantly promote internucleosomal interactions, leading to highly compact polynucleosome conformations. Under these conditions, approximately 30 pN of force was required to disrupt the internucleosomal interactions and release DNA; this force was 36% higher than that required for DNA unwrapping in the absence of PEG. These findings suggest that molecular crowding impacts cellular processes by mechanically regulating chromatin accessibility for regulatory proteins and the passage of motor molecules such as RNA polymerase. ### Competing Interest Statement The authors have declared no competing interest. Japan Society for the Promotion of Science, https://ror.org/00hhkn466, KAKENHI JP18H05534, KAKENHI JP22K06176, KAKENHI JP23K05726, KAKENHI JP24H00884, KAKENHI JP23H05475, KAKENHI JP24H02328 National Institutes for Quantum Science and Technology, https://ror.org/020rbyg91, Budding Research Japan Agency for Medical Research and Development, BINDS JP25ama121025, BINDS JP25ama121009 Japan Science and Technology Agency, https://ror.org/00097mb19, CREST JPMJCR24T3

www.biorxiv.org/content/10.6...

21.01.2026 18:51 — 👍 3    🔁 1    💬 0    📌 0
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Parasex generates highly recombinant progeny in Candida albicans with increased virulence - Nature Microbiology An alternative mating system, termed parasex, produces progeny with high levels of genotypic diversity and is able to fulfil the roles of meiosis when it is absent in the fungal pathobiont Candida alb...

OUT NOW! Parasex generates highly recombinant progeny in Candida albicans with increased virulence

By Robert Fillinger, Scott Filler, Anna Selmecki, Richard Bennett,
Matthew Anderson & colleagues.
#microsky @annaselmecki.bsky.social

www.nature.com/articles/s41...

21.01.2026 16:38 — 👍 18    🔁 13    💬 0    📌 0
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Cell viscosity influences haematogenous dissemination and metastatic extravasation of tumour cells - Nature Materials The viscosity of tumour cells is shown to govern their ability to disseminate through the bloodstream and extravasate, establishing a key biomechanical factor of metastasis.

www.nature.com/articles/s41...

21.01.2026 07:37 — 👍 9    🔁 3    💬 1    📌 0
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The ribosome synchronizes folding and assembly to promote oligomeric protein biogenesis Large oligomeric proteins constitute a major fraction of proteomes, but are difficult to refold in vitro, raising the question of how cells direct their biogenesis. Roeselová and Shivakumaraswamy et a...

www.cell.com/molecular-ce...

20.01.2026 18:25 — 👍 2    🔁 0    💬 0    📌 0
Limited proteolysis-coupled mass spectrometry captures proteome-wide protein structural alterations and biomolecular condensation in living cells The function of a protein is determined by its structure, which may change dynamically in response to post-translational modifications, interaction with other molecules, or environmental factors like temperature. Limited proteolysis-coupled mass spectrometry (LiP-MS) captures such structural alterations on a proteome-wide scale via the detection of altered protease susceptibility patterns of proteins. However, this technique has so far required cell lysis, which exposes proteins to non-native conditions and can disrupt labile interactions such as those occurring within biomolecular condensates. To study protein structures directly within cells, we developed in-cell LiP-MS. We optimized conditions for introduction of proteinase K into human cells using electroporation and validated that intracellular cleavage occurs. In-cell LiP-MS captured not only the known binding of rapamycin to FKBP1A within the cell, but also downstream effects of pathway activation. Moreover, it detected global protein structural alterations upon sodium arsenite treatment and captured the structural dynamics of hundreds of proteins from biomolecular condensates with peptide level resolution and within live human cells. We detected known and novel structural alterations of proteins from stress granules as well as from nuclear speckles and validated alteration of nuclear speckles by fluorescence microscopy. Our dataset provides a resource describing the structural changes of human proteins in response to cellular stress and pinpoints structurally altered regions. Further, comparison of LiP-based structural fingerprints before and after cell lysis revealed which human proteins are susceptible to structural change upon cell lysis, therefore guiding the design of future experiments requiring native protein structures. ### Competing Interest Statement P.P. is a scientific advisor for the company Biognosys AG (Zurich, Switzerland) and an inventor of a patent licensed by Biognosys AG that covers the LiP-MS method used in this work. F.E., R.F., and P.P. have filed a patent application based on this work (European Patent Application No. 23197690). The remaining authors declare no competing interests.

www.biorxiv.org/content/10.1...

19.01.2026 14:54 — 👍 1    🔁 0    💬 0    📌 0
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Butyrolactol A enhances caspofungin efficacy via flippase inhibition in drug-resistant fungi Chen et al. identify the natural product butyrolactol A as an inhibitor of the phospholipid flippase Apt1-Cdc50, which it locks in a nonfunctional state. By disrupting membrane homeostasis and enhanci...

www.cell.com/cell/abstrac...

16.01.2026 14:57 — 👍 0    🔁 0    💬 0    📌 0
Client Challenge

A general one-step protocol to generate impermeable fluorescent HaloTag substrates for in situ live cell application and super-resolution imaging

www.nature.com/articles/s41...

13.01.2026 18:36 — 👍 6    🔁 1    💬 0    📌 0
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Hydrogen/deuterium exchange mass spectrometry analysis of ribosome-nascent chain complexes to study protein biogenesis at the peptide level Nature Protocols, Published online: 12 January 2026; doi:10.1038/s41596-025-01279-wA strategy for isolating Escherichia coli ribosome–nascent chain complexes and analyzing their conformational dynamics and interactors at peptide level using hydrogen–deuterium exchange mass spectrometry is presented.

New Article! Hydrogen/deuterium exchange mass spectrometry analysis of ribosome-nascent chain complexes to study protein biogenesis at the peptide level

12.01.2026 10:48 — 👍 5    🔁 3    💬 0    📌 0
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Why does life explore so few of the forms it could possibly take? Using fractal descriptors, this #scienceadvances paper shows that Earth’s biosphere clusters around simple shapes, reflecting deep evolutionary constraints. @artemyte.bsky.social @manlius.bsky.social www.science.org/doi/pdf/10.1...

11.01.2026 13:22 — 👍 229    🔁 75    💬 5    📌 6

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