Rohit V. Pappu

PS. I owe you a response on rheometry. Will be coming up soon.

Thank you, Lennart! Happy Holidays to you too!

Nuclear speckle proteins form intrinsic and MALAT1-dependent microphases Pre-mRNA processing components in nuclear speckles encompass one or more folded RNA recognition motifs (RRMs) and disordered regions with specific seq…

Nuclear speckle associated RRM-containing proteins are block copolymers. They make size-limited, ordered microphases, tens of nm in size comprising tens of molecules. Speckles are likely clusters or emulsions of distinct microphases and not macrophases www.sciencedirect.com/science/arti...

The announcement that the 2025 Keio prize for Medical Science goes to @virusesimmunity.bsky.social and @brangwynnelab.bsky.social Brangwynne. www.ms-fund.keio.ac.jp/en/prize/ Congratulations to the masters for this well deserved honor. It is gratifying when true quality is recognized.

Now in print: our study using single #fluorogenic molecules to probe the network architecture within #biomolecular #condensates with @rohitpappu68.bsky.social @washuengineers.bsky.social . Teaser video below. Read the full article at doi.org/10.1038/s415... #singlemolecule

Are stress granules crucibles or protective against amyloid fibril formation? Read about our work at Mol Cell: "Tunable metastability of condensates reconciles their dual roles in amyloid fibril formation". Wonderful collaboration with @rohitpappu68.bsky.social and other colleagues (see next post)!

Research untangles role of stress granules in neurodegenerative disease Researchers at Washington University in St. Louis and St. Jude Children’s Research Hospital have found that biomolecular condensates play a role in suppressing the effects of ALS-causing mutations.

Biomolecular condensates are shape shifting bits of DNA, RNA and proteins that “condense” molecules to key locations inside our cells. I call em "power blobs" cuz I'm fun like that. 🧪 🩺 Research from @rohitpappu68.bsky.social with @stjuderesearch.bsky.social

source.washu.edu/2025/05/rese...

Do read the result of this collaboration that dissected the reaction from all sides, even showing how beautifully the results transfer over into cells, where hnRNP-A1 with ALS-associated mutations can be redesigned to generate wild-type-like stress granule phenotypes through tunable metastability.

Using kinetic models inspired by Tuomas Knowles, we predicted that efflux of material from metastable condensates becomes rate-limiting for fibril formation. Efflux slows as metastability increases. Experiments with @priya-r-banerjee.bsky.social confirmed these predictions.

The Ostwald rule of stages is central to thinking about how stable vs. metastable states contribute to nucleation & growth of fibrils. This important linkage between thermodynamics & kinetics is often glossed over generating confusion about the role of condensates in fibril formation.

Relative stabilities of condensates vs. fibrils turned out to be crucial for guiding mechanistic studies. Measurements of relative stabilities showed that condensates are metastable. Condensate interiors ≠ crucibles & the sink potentials of condensates are tunable via tunable metastability.

With @tanjamittag.bsky.social we asked if A1-LCD condensates are protective or crucibles for amyloid fibril formation. Their interfaces enable fibril nucleation but their interiors suppress fibril formation. Insights were transferrable to stress granules in cells.
doi.org/10.1016/j.mo...

Myosin makes the moves to keep cell processes humming along Washington University in St. Louis and Duke University researchers show how directed motions combined with protein interactions influence phase separation and the maintenance of biomolecular...

engineering.washu.edu/news/2025/My.... @luciastrader.bsky.social

This collaboration with @luciastrader.bsky.social‬ emerged as the result of a serendipitous interaction in Zurich in 2022. Lucia presented data for movement of ARF condensates during her talk & I was convinced this was Motility Influenced Phase Separation (MIPS). And so, the collaboration began!

The Center for Biomolecular Condensates - making things happen!

A wonderful collaboration between us, @rohitpappu68.bsky.social and the Knowles lab is now online, exploring anisotropies of molecules at the interfaces of RNA condensates! Congratulations Nadia, Mina, and Yuanxin! @washuengineers.bsky.social @washu.bsky.social

This work helps uncover rules regarding organization at condensate interfaces while also showing how systems with interfacial preferences can be designed & measurements can help extract the organization at interfaces. Collaborations with @lewlab.com, Knowles lab, driven by Nadia Erkamp & Mina Farag

Computations show that adsorbents prefer more parallel orientations whereas scaffolds prefer more perpendicular orientations at interfaces. Unprecedented single fluorogen tracking quantifies dynamical anisotropy at interfaces with faster motions parallel to interfaces.

Differential interactions determine anisotropies at interfaces of RNA-based biomolecular condensates - Nature Communications Experiments and computations show that the organization and dynamics of molecules within and at interfaces of biomolecular condensates are governed by differential interaction strengths leading to the...

We investigated the interfacial orientations of scaffold molecules vs. adsorbents in model condensates formed by pairs of RNA molecules with PEG. Experiments identify purine-rich RNAs as scaffolds & pyrimidine-rich RNAs as adsorbents that undergo wetting transitions.
www.nature.com/articles/s41...

Backbone-mediated weakening of pairwise interactions enables percolation in peptide-based mimics of protein condensates - Communications Chemistry Biomolecular condensates formed by intrinsically disordered protein condensates are known to be semidilute solutions, however, the molecular interactions in the dilute versus dense phases remain under...

All atom simulations of peptides were used to investigate differences in pair interactions in dilute vs. dense phase mimics of condensates. Backbone-mediated interactions were found to weaken pairwise associations in dense phases giving rise to percolated networks. doi.org/10.1038/s420...

Uncovering the electrochemistry of condensates Researchers at Washington University in St. Louis are discovering the electrochemical properties of biomolecular condensates which could help in development of cancer or ALS treatments.

More exciting news from the Center for Biomolecular Condensates at WashU McKelvey School of Engineering - Discoveries through technological innovations and conceptual leaps
engineering.washu.edu/news/2025/Un...

A closer look at biomolecular ‘Silly Putty’ Researchers at Washington University in St. Louis have developed a method to peer into biomolecular condensates, which could lead to a better understanding of condensate functions and their impairment...

source.washu.edu?p=703478&pre...

Postdoctoral scholars shape academic life, bolster innovation and collaboration Postdoctoral trainees share their experiences working in WashU’s Department of Biomedical Engineering

The postdoc experience in BME at WashU
engineering.washu.edu/news/2025/Po...

With bsky.app/profile/lewl... we peered into condensates using single fluorogen imaging. Nanoscale hubs form, move, & disassemble on a range of timescales. A structural basis for condensate viscoelasticity. Need to rethink popular ideas. #Condensates≠simple-liquids
www.nature.com/articles/s41...

check out the latest from Kiersten Ruff, Rohit Pappu and team!

a molecular logic for protein disordered domains 🤩

Molecular grammars of intrinsically disordered regions that span the human proteome Intrinsically disordered regions (IDRs) of proteins are defined by functionally relevant molecular grammars. This refers to IDR-specific non-random amino acid compositions and non-random patterning of...

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

Nuclear speckle proteins form intrinsic and MALAT1-dependent microphases Nuclear speckles are enriched in serine / arginine rich splicing factors (SRSFs), such as SRSF1. Splicing factors and proteins such as TDP43 concentrate into distinct speckle territories to enable pre...

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

What Felt Impossible Became Possible | dansinker.com

dansinker.com/posts/2025-0...

🚀 First Bluesky Post! 🎉 VMD 2.0 Alpha is here! Released today at BPS 2025, this is the biggest update in 30 years—new UI, real-time ray tracing, fast surfaces, UHD & touchscreen support. Monthly updates coming in 2025! Try it now! #VMD #BPS2025 #MolecularVisualization
www.ks.uiuc.edu/Research/vmd...

Intrinsically Disordered Proteins: A Peek Away from the Lampost YouTube video by WebsEdge Science

For our first scientific session spotlight we are "Peeking away from the lampost" with Dr. Rohit Pappu as he joins us to discuss intrinsically disordered proteins. @rohitpappu68.bsky.social @biophysicalsoc.bsky.social #bps2025 youtu.be/pAP2lBWBiGU