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robineclee.bsky.social @robineclee.bsky.social · 03/12/2025

Our “zoo experiment” in Cell Reports @cellpress.bsky.social shows that extracellular cytokine molecules are encoded by surface receptors as quantized signaling units, independent of ligand affinity. A new principle for how cells sense and interpret their environment. www.cell.com/cell-reports...

cell.com

NEMO recruitment at single cytokine-receptor complexes shows quantized dynamics independent of ligand affinity

Kim et al. leverage natural variation in IL-1β affinity across species to show that while ligand affinity sets activation thresholds, each IL-1 receptor signaling complex outputs a fixed, quantized bu...

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Reposted by @robineclee.bsky.social

Computational & Systems Biology Dept. at Pitt @csbpitt.bsky.social · 15/08/2025

In the complex world inside our bodies, timing can be everything. A new study from Steven Smeal and Robin E.C. Lee reveals the timing of molecular signals can change how cells respond to their environment, with implications for cancer treatment and drug discovery. Read more: rdcu.be/ezTxF

rdcu.be

Time-varying stimuli that prolong IKK activation promote nuclear remodeling and mechanistic switching of NF-κB dynamics

Nature Communications - Cells rely on limited numbers of transmembrane receptors to process signals from dynamic microenvironments. Using microfluidics and endogenous reporters, the authors track...

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robineclee.bsky.social @robineclee.bsky.social · 13/08/2025

In @natcomms.nature.com, we used robot-controlled cytokine pulses and imaging single receptor complexes and TF dynamics reveal that repeat, dose-conserving stimulation prolongs NEMO/IKK activation and shifts NF-κB dynamics via chromatin remodeling, enabling accurate single-cell models rdcu.be/ezTxF

rdcu.be

Time-varying stimuli that prolong IKK activation promote nuclear remodeling and mechanistic switching of NF-κB dynamics

Nature Communications - Cells rely on limited numbers of transmembrane receptors to process signals from dynamic microenvironments. Using microfluidics and endogenous reporters, the authors track...

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robineclee.bsky.social @robineclee.bsky.social · 22/04/2025

We argue that quantized signaling may be a powerful strategy for cells. From ensuring reliable messaging, even in changing and noisy environments, to something akin to a molecular Morse code, where time-domain messages communicate complex environmental cues.

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robineclee.bsky.social @robineclee.bsky.social · 22/04/2025

2. Once the receptor turns on it’s all the same: Regardless of species, each activated complex recruits a quantized number of kinases with the same dynamics. i.e., the “on” signal is stereotyped, suggesting each activated complex delivers a digital packet of signaling information into the cell.

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robineclee.bsky.social @robineclee.bsky.social · 22/04/2025

1. Affinity shapes sensitivity: Species-specific affinity, or how tightly the receptor and IL-1β variant binds the human receptor, affects how sensitive the cells are to the cytokine in terms of the number and timing of receptor activation. This matches expectations from classical signaling.

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robineclee.bsky.social @robineclee.bsky.social · 22/04/2025

We then used purified IL-1β from across a range of species and exposed human cells (engineered to express an endogenous reporter for activated signaling complexes) to each. By pairing live-cell imaging with computational models and single particle tracking we found two critical insights.

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robineclee.bsky.social @robineclee.bsky.social · 22/04/2025

Using a mixture of phylogenetic and structural analysis, we found that IL-1β – a key inflammatory cytokine - from a panel of species is likely to engage productively with human receptors, albeit with different affinities.

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robineclee.bsky.social @robineclee.bsky.social · 22/04/2025

In our preprint, we present results from what we call our “zoo experiment”. Here, @cmupittcompbio.bsky.social Ph.D. students Annie Kim and Benjamin Krummenacher explore whether naturally occurring variation between species could test whether cytokines follow the rules of classical signaling.

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robineclee.bsky.social @robineclee.bsky.social · 22/04/2025

In classical cell signaling, the strength of a signal depends on how long a ligand interacts with its receptor – for a high affinity interaction the duration is longer, and so is the resulting signal. What happens then, when the ligand comes from a different species? Does the signal go through?

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robineclee.bsky.social @robineclee.bsky.social · 22/04/2025

When a bovine cytokine talks to a human cell: Lessons from cross-species signaling experiments. 😊 🐱 🐰 🐁 🐀 🐄 www.biorxiv.org/content/10.1...

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