and Cliff @brangwynnelab.bsky.social for all the support and guidance through this journey! (10/10)

This work reflects the effort of many amazing collaborators: Lifei Jiang, Peter Metzger, Troy Comi, Aya Abu-Alfa, @qiweiyu.bsky.social, Margaret Ebert, Minkyu Lee, Lenny Wiesner, Maya Butani, Claire Weaver, Andrej Košmrlj, Ileana Cristea….. (9/10)

Take home: Ribosomes undergo molecular aging in living cells.

As ribosomes age, translation efficiency shifts, elongation defects increase at basic sequences, and ribosome collisions become more frequent.

This suggests ribosome aging directly shapes translation dynamics. (8/10)

Does ribosome molecular aging occur in vivo?

Using our strategy in C. elegans, we tracked ribosomes that persisted ≥8 days.

These long-lived ribosomes showed reduced association with translating pools, linking ribosome molecular aging to organismal aging. (7/10)

Are aging ribosomes sufficient to drive these translation changes?

Using a HaloPROTAC strategy, we selectively degraded newly made ribosomes, enriching the pool of older ones.

This alone recapitulates the translation defects seen in aged ribosomes! (6/10)

Not all ribosomes age equally.

Profiling rRNA modifications reveals that collisions driven by aged ribosomes are enriched for ribosomes lacking the pseudouridine Ψ18S-210, demonstrating to a vulnerable ribosome subpopulation. (5/10)

Why do aged ribosomes translate some mRNAs less efficiently?

Older ribosomes pause more during elongation.

Pausing sites are enriched for basic amino acids (K/R), suggesting molecular aging makes ribosomes more prone to stalling at polybasic sequences. (4/10)

Using our strategy, we performed molecular age-selective Ribo-seq to compare aged ribosomes with the steady-state pool.

Result: ribosome molecular aging shapes the translation efficiency of specific transcripts classes! (3/10)

To study ribosome molecular aging, we developed a bio-orthogonal HaloTag strategy to label ribosomes in living cells.

This enables us to track ribosomes over time and purify defined age populations, allowing us to study how ribosome composition and function change with age. (2/10)

Some molecular machines, like ribosomes, can persist for long periods of time in cells.

Could molecular aging of ribosomes shape how proteins are made?

In our new preprint we track ribosomes as they age in cells and uncover unexpected effects on translation (1/10)

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

Congratulations to our grad student Lifei Jiang!!!!! Well deserved