Author Archives: tjj3

Opening for Research Technologist I

We currently have an opening for a full time tech position: https://psu.jobs/job/85310

This is a great position for somebody looking to get some concentrated time in the lab to develop their research skills. It could be a good fit for an early career tech or a great transitional job for a graduating student looking to strengthen their research experience before moving on to professional school. If you don’t fit those categories but think the job might be a fit for you, apply – you might be right!

New lab publications

We had a couple of nice publications late last year that are worth a mention:

The S6 gate in regulatory Kv6 subunits restricts heteromeric K+ channel stoichiometry http://jgp.rupress.org/content/150/12/1702

This paper was the core of Aditya’s thesis and is a great example of how you can use evolution to highlight key features of proteins. K+ channels are tetrameric and can typically form as homotetramers composed of four identical subunits. However, some subunits have evolved a “regulatory” phenotype in which they can no longer make homotetramers and instead depend on mixing with other closely-related K+ channel subunits to form functional channels, often in an unusual asymmetric 3:1 ratio. We identified sequence changes that correlated with evolution of the regulatory phenotype and found that the interface between subunits in the lining of the pore itself played a key role in determining channel composition. Previously, it had been thought that a cytoplasmic sorting domain, T1, was fully responsible for channel subunit composition. We proposed a two-step model of how you can evolve asymmetric channels that involves sequential mutation of T1 and the pore. This is one of those typical JGP papers with heroically complicated biophysics experiments. We also received a great assist from the Hancock lab who worked with us to count subunits in individual channels using fluorescent tags.

Evolution and Structural Characteristics of Plant Voltage-Gated K+ Channels http://www.plantcell.org/content/early/2018/11/01/tpc.18.00523

This a review Greg and I wrote with Sally on the evolution of Plant Voltage-Gated K+ channels and the CNBD channel superfamily to which they belong. We managed to squeeze a lot of new analyses into it, so its sort of a hybrid review/research article. Here is my favorite thing in the article: 1) CNBD superfamily channels, which include the plant channels and a wide range of animal channels that control sensory perception, neuronal excitability and heartbeat, come from a prokaryotic ancestor that is common in eubacterial lineages but appears to be absent (at least so far) in the Archaea. Since eukaryotes evolved from the Archaeal lineage, that could mean we picked up the CNBD channel superfamily by lateral gene transfer. There of course are plenty of documented cases of lateral gene transfer, but I still think its amazing that the channels that we use to see and smell and the channels that plants depend on to open and close their leaf pores may have been “borrowed” from bacteria. The Plant Cell is of course nothing new to Sally, but it was nice for me to bag another top journal for my “life list”.

Research Opportunities

Its hard to believe the semester officially starts next week! Welcome to new students and welcome back to those who are returning! Our lab is looking for new members at both the undergraduate and graduate levels. We have a wide variety of projects examining the function and evolution of neurons and neuronal signaling, and we are looking for highly motivated students to expand our team. If you are looking for research experience in cellular and molecular neurobiology and are interested in a career in the biological or biomedical sciences, consider joining us. All inquiries should be directed to Tim Jegla (tjj3@psu.edu)

Complex nerve-cell signaling traced back to common ancestor of humans and sea anemones

Check out the Eberly College news story on our PNAS paper exploring the evolutionary origins of voltage-gated K+ channels. We find that many of the key channel types that shape electrical signals in our neurons were actually missing in the first nervous systems. However, they are still ancient and we can trace them all back to a common ancestor of humans and cnidarians (animals like sea anemones and jellyfish). We want to know why – what important event was going on in nervous system evolution at that time?

http://science.psu.edu/news-and-events/2015-news/Jegla2-2015

Early evolution of a cardiac ion channel

Check out this Huck Institute story on our 2014 PNAS paper exploring the functional evolution of Erg K+ channels, which play a key role in repolarizing cardiac action potentials. We show the specialized way these channels work evolved before we split from animals like sea anemones hundreds of millions of years before they picked up a role in the heart.

https://www.huck.psu.edu/content/about/news-archive/human-heart-beats-using-nearly-billion-year-old-molecular-mechanism