Ian Yen
@ianyyen.bsky.social
Type IV Pilus | Aspiring e- cryo microscopist | PhD Candidate | UofToronto | P. Lynne Howell lab 🇨🇦🔬🦠
Reposted by Ian Yen
Great collaboration with @brunlabcaulo.bsky.social for resolving the Tad pilus machine structure by cryo-ET. Beautiful work by graduate students James Iarocci and Ryu Williston in our lab.
Preprint:https://www.biorxiv.org/content/10.1101/2025.11.05.686773v1
Preprint:https://www.biorxiv.org/content/10.1101/2025.11.05.686773v1
November 6, 2025 at 3:58 PM
Great collaboration with @brunlabcaulo.bsky.social for resolving the Tad pilus machine structure by cryo-ET. Beautiful work by graduate students James Iarocci and Ryu Williston in our lab.
Preprint:https://www.biorxiv.org/content/10.1101/2025.11.05.686773v1
Preprint:https://www.biorxiv.org/content/10.1101/2025.11.05.686773v1
Reposted by Ian Yen
New paper alert! We used our fav technique, genetic suppression, to understand how FimX controls function of the T4P PilB motor ATPase in Pseudomonas aeruginosa. Great collab with the Ellison lab at U Georgia who helped with some fancy microscopy to capture pilus dynamics! doi.org/10.1371/jour...
Twitching motility suppressors reveal a role for FimX in type IV pilus extension dynamics
Author summary Type IV pili enable Pseudomonas aeruginosa to attach to surfaces, move (twitch), and form biofilms. Pilus extension is powered by the motor protein PilB, which is regulated by other fac...
doi.org
October 13, 2025 at 8:18 PM
New paper alert! We used our fav technique, genetic suppression, to understand how FimX controls function of the T4P PilB motor ATPase in Pseudomonas aeruginosa. Great collab with the Ellison lab at U Georgia who helped with some fancy microscopy to capture pilus dynamics! doi.org/10.1371/jour...
Reposted by Ian Yen
New paper! Specific PilA and PilY1 sequences make PilU dispensable for T4P-dependent twitching motility in P. aeruginosa. However, most suppressors still had high cAMP levels from loss of PilU, showing that motility and surface sensing responses can be uncoupled.🧐 ⏩ journals.asm.org/doi/10.1128/...
Separation of Pseudomonas aeruginosa type IV pilus-dependent twitching motility and surface-sensing responses | mBio
The ability of bacteria to sense and respond to contact with surfaces is important
for triggering changes in secondary messenger levels and gene expression, leading
to the formation of biofilms and in...
journals.asm.org
October 7, 2025 at 5:09 PM
New paper! Specific PilA and PilY1 sequences make PilU dispensable for T4P-dependent twitching motility in P. aeruginosa. However, most suppressors still had high cAMP levels from loss of PilU, showing that motility and surface sensing responses can be uncoupled.🧐 ⏩ journals.asm.org/doi/10.1128/...
Reposted by Ian Yen
Breathing polluted air increases the risk of #osteoporosis, growing evidence shows.
Learn more: scim.ag/4lUQBrf #ScienceMagArchives
Learn more: scim.ag/4lUQBrf #ScienceMagArchives
August 2, 2025 at 2:07 PM
Breathing polluted air increases the risk of #osteoporosis, growing evidence shows.
Learn more: scim.ag/4lUQBrf #ScienceMagArchives
Learn more: scim.ag/4lUQBrf #ScienceMagArchives
Reposted by Ian Yen
When particles have orientation bias, the resulting maps are often streaked along the missing directions. In this case study, we cover why orientation bias produces anisotropic #cryoEM maps and how you may be able to recover from it!
guide.cryosparc.com/processing-d...
guide.cryosparc.com/processing-d...
July 23, 2025 at 12:29 PM
When particles have orientation bias, the resulting maps are often streaked along the missing directions. In this case study, we cover why orientation bias produces anisotropic #cryoEM maps and how you may be able to recover from it!
guide.cryosparc.com/processing-d...
guide.cryosparc.com/processing-d...
Reposted by Ian Yen
New paper alert! PhD candidate Nathan Roberge is studying regulation of the #T4P assembly ATPase PilB and identified suppressors of FimX with enhanced motility. Where did they map? Find out here: www.biorxiv.org/content/10.1...
Twitching motility suppressors reveal a role for FimX in type IV pilus extension dynamics
In Pseudomonas aeruginosa, retractable protein filaments called type IV pili (T4P) facilitate surface adherence, sensing, and directional movement known as twitching motility. T4P are necessary for th...
www.biorxiv.org
July 15, 2025 at 5:12 PM
New paper alert! PhD candidate Nathan Roberge is studying regulation of the #T4P assembly ATPase PilB and identified suppressors of FimX with enhanced motility. Where did they map? Find out here: www.biorxiv.org/content/10.1...
Fantastic collaboration with @ckellison.bsky.social where we demonstrate functional divergence of FimX to regulate type IV pilus positioning along the long axis of Acinetobacter baylyi
Excited to share the newest preprint from the lab for my first post! Driven by @tayellisonwrites.bsky.social and @ianyyen.bsky.social with Lynne Howell we show the protein FimX has diverged in function away from regulating pilus extension to instead regulate pilus localization in A. baylyi
FimX regulates type IV pilus localization via the Pil-Chp chemosensory system in Acinetobacter baylyi
Type IV pili (T4P) are widespread dynamic appendages required for diverse prokaryotic behaviors including twitching motility, biofilm formation, and DNA uptake leading to natural transformation. Altho...
www.biorxiv.org
May 22, 2025 at 6:01 PM
Fantastic collaboration with @ckellison.bsky.social where we demonstrate functional divergence of FimX to regulate type IV pilus positioning along the long axis of Acinetobacter baylyi
Reposted by Ian Yen
ChimeraX daily builds can predict small complexes of proteins, nucleic acids and small molecules using Boltz on your Mac, Windows or Linux computer without Nvidia graphics. www.rbvi.ucsf.edu/chimerax/dat...
May 1, 2025 at 12:35 AM
ChimeraX daily builds can predict small complexes of proteins, nucleic acids and small molecules using Boltz on your Mac, Windows or Linux computer without Nvidia graphics. www.rbvi.ucsf.edu/chimerax/dat...
Thrilled to announce my first PhD publication in Nature Comms! We determined structures of the Tad pilus ATPase CpaF from Caulobacter. We use these structures to propose how CpaF employs a rotary mechanism of catalysis to drive Tad pilus assembly.
www.nature.com/articles/s41...
www.nature.com/articles/s41...
Conformational changes in the motor ATPase CpaF facilitate a rotary mechanism of Tad pilus assembly - Nature Communications
The bacterial Tad pilus extends and retracts using a single bifunctional ATPase CpaF. Here, the authors employ cryo-EM, fluorescent microscopy, and AlphaFold modelling to propose how a rotary mechanis...
www.nature.com
April 24, 2025 at 3:29 AM
Thrilled to announce my first PhD publication in Nature Comms! We determined structures of the Tad pilus ATPase CpaF from Caulobacter. We use these structures to propose how CpaF employs a rotary mechanism of catalysis to drive Tad pilus assembly.
www.nature.com/articles/s41...
www.nature.com/articles/s41...
Reposted by Ian Yen
Learn principles of image processing to determine macromolecular structures by #cryoEM: Sign up for EMBO Practical Course on Image processing for cryo-electron microscopy in London, UK, 9–16 September
Deadline: 25 April
meetings.embo.org/event/25-cry...
#EMBOcryoEM #EMBOevents 🧪
Deadline: 25 April
meetings.embo.org/event/25-cry...
#EMBOcryoEM #EMBOevents 🧪
Image processing for cryo-electron microscopy
Cryo electron microscopy (cryo EM) is a major structural biology method for studying macromolecular complexes and cellular structures in their native states. Stable high resolution cryo microscopes, …
meetings.embo.org
March 26, 2025 at 8:54 AM
Learn principles of image processing to determine macromolecular structures by #cryoEM: Sign up for EMBO Practical Course on Image processing for cryo-electron microscopy in London, UK, 9–16 September
Deadline: 25 April
meetings.embo.org/event/25-cry...
#EMBOcryoEM #EMBOevents 🧪
Deadline: 25 April
meetings.embo.org/event/25-cry...
#EMBOcryoEM #EMBOevents 🧪
Reposted by Ian Yen
1/10 🧵 Injecting some science in your feed: Happy to share another chapter in our investigation of bacterial surface sensing. We describe the role of CpaL, a minor pilin-like protein, a key player in surface sensing and adhesion in Caulobacter crescentus. #microsky www.biorxiv.org/content/10.1...
Stimulation of the Caulobacter crescentus surface sensing pathway by deletion of a specialized minor pilin-like gene
Bacteria colonize surfaces through complex mechanisms of surface sensing. Pili are dynamic bacterial appendages that play an important role in this process. In Caulobacter crescentus , tension on retr...
www.biorxiv.org
February 19, 2025 at 8:20 AM
1/10 🧵 Injecting some science in your feed: Happy to share another chapter in our investigation of bacterial surface sensing. We describe the role of CpaL, a minor pilin-like protein, a key player in surface sensing and adhesion in Caulobacter crescentus. #microsky www.biorxiv.org/content/10.1...