ASCB 2023 in Boston with Yiling Lan and Yan Wu

by Heidi Hehnly in ,


Lan and Yan had a great first visit to ASCB/Cell Bio meeting this year where Lan presented a poster and Yiling a talk and a poster! They both did great, met lots of people, and asked great questions. We also got to hang with old friends (Ana Vertii, Hui-Fang Hung, Shashi Kant, and Benedict Delaval) and eat excellent food! We got to also hang out with Syracuse University Patteson and Castaneda Labs. With Alison Patteson (Physics, SU) giving a great talk in the Vimentin section! Overall it was a great trip and we can’t wait to do it again.


Check out the new Castaneda Lab Paper that we assisted with!

by Heidi Hehnly in ,


Under stress, certain eukaryotic proteins and RNA assemble to form membraneless organelles known as stress granules. The most well-studied stress granule components are RNA-binding proteins that undergo liquid-liquid phase separation (LLPS) into pro…

Under stress, certain eukaryotic proteins and RNA assemble to form membraneless organelles known as stress granules. The most well-studied stress granule components are RNA-binding proteins that undergo liquid-liquid phase separation (LLPS) into protein-rich droplets mediated by intrinsically disordered low-complexity domains (LCDs). Here we show that stress granules include proteasomal shuttle factor UBQLN2, an LCD-containing protein structurally and functionally distinct from RNA-binding proteins. In vitro, UBQLN2 exhibits LLPS at physiological conditions. Deletion studies correlate oligomerization with UBQLN2’s ability to phase-separate and form stress-induced cytoplasmic puncta in cells. Using nuclear magnetic resonance (NMR) spectroscopy, we mapped weak, multivalent interactions that promote UBQLN2 oligomerization and LLPS. Ubiquitin or polyubiquitin binding, obligatory for UBQLN2’s biological functions, eliminates UBQLN2 LLPS, thus serving as a switch between droplet and disperse phases. We postulate that UBQLN2 LLPS enables its recruitment to stress granules, where its interactions with ubiquitinated substrates reverse LLPS to enable shuttling of clients out of stress granules.