Neuroscience Faculty Members Named AAAS Fellows

Leslie Griffith & Gina Turrigiano-2017 AAAS Fellows

Leslie Griffith (left) and Gina Turrigiano (right)

Leslie Griffith and Gina Turrigiano have been named American Association for the Advancement of Science (AAAS) Fellows for 2017. This is in recognition of their contributions and scientific leadership in the field of Neuroscience.

Leslie Griffith, Nancy Lurie Marks Professor of Neuroscience and Director of the Volen Center for Complex Systems, studies sleep and memory using Drosophila melanogaster.

Gina Turrigiano is the Joseph Levitan Professor of Vision Science. Her lab studies the mechanisms of homeostatic synaptic plasticity and their effects in developing and functioning cortex.

Vice Provost for Research Edward Hackett is also a 2017 AAAS Fellow in the Section on History and Philosophy in Science.

Griffith, Turrigiano, Hackett and the other Fellows for 2017 will be recognized on Saturday, Feb. 17, 2018 at the 2018 AAAS Annual Meeting in Austin, Texas.

Read more at BrandeisNow.

John Lisman (1944-2017)

Chair of Biology Piali Sengupta wrote:

It is with great sadness that I am writing to let you know that John Lisman passed away last night. He passed away peacefully surrounded by his family. John was an influential and creative scientist and a very good friend to all of us in Biology and Neuroscience. We are glad that we had the opportunity to honor him and hear from him at the Volen Retreat last week. He will be much missed.

John’s talk at the Volen Retreat earlier this month, delivered by video conference, is available here: The critical role of CaMKII in memory storage: 6 key physiological and behavioral tests

The family has asked that in lieu of flowers people consider contributing to the John Lisman Memorial Scholarship

Update: The Memorial Service, taking place at 2 p.m. Thu Oct 26, will be live streamed. Brandeis community members can watch the live streaming in real time in Gerstenzang 121 as well as the Shapiro Science Center level 1 library. There will be a reception at the Brandeis Faculty Club at 3:30 open to the community.

We also wanted to share some tweets from past students and colleagues:

We also received this longer tribute from Michael Kahana:

I was greatly saddened to hear the news that John Lisman passed away this weekend. I spoke with him just a few weeks ago and was greatly looking forward to his upcoming visit to Penn. Although he told me of his illness, I was hoping to have a little more time with my good colleague and friend. Upon learning of his passing, I wanted to write down a few memories to share with friends and colleagues who knew John well.

I vividly recall when I first met John, at an evening gathering at his home that I attended just prior to joining the faculty at Brandeis (this may have been a precursor to the famous Boston Hippocampus meetings that John helped organize). The meeting was teaming with energy, and John welcomed me warmly, introducing me to other scientists in the room. John had recently become very interested in human memory, and as a newly minted PhD working on memory, John took me under his wings, teaching me about neurophysiology and quizzing me enthusiastically about the psychology of memory, a field that John was keen to master as quickly as possible.

John was a polymath, bursting with creative energy, and capable of seeing connections between diverse fields. Over the subsequent decade at Brandeis, John had an enormous influence on my career and research direction, introducing me to theta and gamma rhythms, and teaching me about countless topics in neurophysiology. On a typical day in the Volen Center, John would rush into my lab eager to share a new discovery or ask me a question about a study of memory that he had just learned about. He had this incredibly-infectious scientific curiosity, and he was always abundantly generous with his time, both with me and my students.

I particularly remember the early days when John was developing the LIJ (Lisman-Idiart-Jensen) model, and trying to learn as much as he could about the Sternberg task and other related phenomena in the field of human memory. Although I frequently challenged John on this front, he kept at it, continuing to refine the model together with Ole Jensen until they were able to answer many of the most serious objections. I just saw that the original paper was cited more than 1,200 times, and several of the follow up papers are well into the many hundreds of citations. This is arguably the most creative neurophysiological model of a cognitive function, and the best example of an attempt to link detailed physiological measurements to behavioral measures of human memory.

We have all lost a great friend, colleague, and mentor, and the field of neuroscience has lost one of its shining stars. I want to share my deepest sympathies with all of you who knew and loved John.

May his family be comforted among the mourners of Zion and Jerusalem.
Mike Kahana

Thomas Reese shared his thoughts:

John, your intellect and spirit lighted more than 30 summers my life at the MBL in Woods Hole.  You were a reference point for neurobiology there, holding court at your favorite table at the Kidd, at the far end of the dock.  A cherished invitation to lunch at exactly 12:00, with interesting synapse people passing though, or to hear a deluge of you new ideas about how a synapse is, or should be, put together.  Occasionally an invitation to dinner outside, behind your house with talk of many things…..joined by the delightful Natashia and other interesting people….discussing well into the night.

If Woods Hole is a little scientific Athens, you were our Socrates, lurking on Milfield. questioning in your disarming, open open way…bringing out the truth.  You were our Dogenes. searching Gardner Road for a man with the honest truth.

John, ,…John..it will seem empty there without you…you
will be very much missed..Tom Reese.     NIH

CaMKII: some basics to remember

The theme of Thursday’s Volen Center for Complex Systems annual retreat will be Breakthroughs in understanding the role of CaMKII in synaptic function and memory and honors the pioneering work of John Lisman. To help bring non-experts up to speed, we asked Neuroscience Ph.D. students Stephen D. Alkins and Johanna G. Flyer-Adams from the Griffith lab at Brandeis for a quick primer on CaMKII.

What’s a protein kinase? 

Protein kinases are enzymes that act by adding phosphate groups to other proteins – a process called phosphorylation. Phosphorylation of a protein usually initiates a cascade of downstream effects such as changes in the protein’s 3D shape,  changes in its interactions with other proteins, changes in its activity and changes in its localization. In causing these types of changes, kinases facilitate some of the most essential cellular and molecular processes required for survival and proper functionality.

Aren’t there lots of protein kinases? What makes CaMKII special? 

Among the roughly 500+ genes in the human genome encoding protein kinases, a kinase known as calcium (Ca2+)/calmodulin-dependent protein kinase II (CaMKII) phosphorylates serine or threonine residues in a broad array of target proteins.  Though found in many different tissues (skeletal muscle, cardiac muscle, spleen, etc.), there is a lot of CaMKII in the brain– about 1% of total forebrain protein and 2% of total hippocampal protein (in rats). Previous research, including pivotal contributions from the Lisman Lab at Brandeis University working in mammalian brain, has identified CaMKII as a cellular and molecular correlate of learning and memory through its multiple roles governing normal neuronal structure, synaptic strength, plasticity, and homeostasis. The Griffith Lab has been instrumental in demonstrating that these roles of the kinase are conserved in invertebrates.

Why do we think CaMKII might play a role in memory?

a) Location!

As previously mentioned, CaMKII accounts for up to 2% of all proteins in memory-important brain regions like the hippocampus. It’s also highly abundant at neuronal synapses, where neurons communicate with each other.

b) Function!

Memory is thought to require a process called long term potentiation (LTP) where two neurons, in response to environmental changes, will change the strength of the synaptic connections by which they communicate with each other—these changes will last even after the environmental input has disappeared. We know that CaMKII is required for LTP. We also know that the increases in neuronal calcium levels that accompany neuronal activation and cause LTP also allow CaMKII to phosphorylate itself. This autophosphorylation of CaMKII changes its kinase activity so that CaMKII can stay active well past the window of neuronal activation, essentially ‘storing’ the memory of previous neuronal activity—much like LTP!

c) Structure!

Ultimately, the issue with ‘molecular memory’ is that all proteins degrade over time, causing one to ask how we can remember things for so long when the original proteins that stored that memory no longer exist. CaMKII is such an exciting candidate for molecular memory because it is mostly found as a dodecameric holoenzyme—this means that CaMKII likes to exist as a big assembly of twelve identical CaMKII subunits. However, each CaMKII subunit retains its kinase activity even when all twelve are assembled. What’s interesting is that the autophosphorylation and activation of one CaMKII subunit (which happens when neurons are activated and intracellular calcium levels rise) actually makes it easier for the other CaMKII subunits in the twelve-unit holoenzyme to become autophosphorylated and activated. This means that maybe when an activated subunit is old and get degraded, another new CaMKII subunit could take its place among the twelve-unit holoenzyme—and become activated just like the old subunit, allowing for the ‘molecular memory’ to last beyond when proteins degrade!

CaMKII phosphorylation and activationCaMKII in more detail…

Calcium binds to the small protein calmodulin and forms (Ca2+/CaM), which acts as a ‘second messenger’ that increases in concentration when neurons are activated. CaMKII relies on calcium/calmodulin (Ca2+/CaM) binding to activate an individual domain containing a regulatory segment.  In conditions of low calcium, elements within the CaMKII regulatory segment will have less affinity for (Ca2+/CaM) binding, keeping CaMKII in an autoinhibited state.  In conditions of high calcium, (Ca2+/CaM) binding initiates phosphorylation at three threonine residue sites, including Thr286 which prevents rebinding of the regulatory segment, thus keeping CaMKII constitutively active even when calcium levels fall.  In this activated state CaMKII can autophosphorylate inactivated intra-kinase domains, and will undergo subunit exchange with neighboring inactivated CaMKII holoenzymes. Furthermore, mutation of CaMKII residues or binding sites in target proteins, such as postsynaptic glutamate (AMPA) receptors, disrupts establishment of long-term potentiation (LTP) in neurons.  Together, CaMKII’s role as molecular switch that bidirectionally, and autonomously regulates activity in neurons has earned it the illustrious title of a “memory molecule.”

What amino-acid manipulations might I hear about?

a) T286A:

Changing a threonine in a phosphorylation site to an alanine prevents phosphorylation at that site. Blocking Thr286 phosphorylation with a T286A mutation prevents CaMKII generation of autonomous activity that disrupts neuronal activity and results in learning deficits.

b) T286D:

Changing a threonine to an aspartate puts a negative charge at the site, often making it act like it’s always phosphorylated. In the case of CaMKII, a T286D mutation renders the kinase constitutively active, which can interrupt normal LTP induction and normal memory storage and acquisition.

To learn more:

Rosbash, Hall & Young Awarded Nobel Prize

Michael Rosbash, Nobel Laureate

Brandeis researchers Michael Rosbash, the Peter Gruber Endowed Chair in Neuroscience, and Professor Emeritus of Biology Jeffrey C. Hall have received this year’s Nobel Prize in Physiology or Medicine, together with Michael Young from The Rockefeller University,  for their pioneering work on the molecular mechanisms controlling circadian rhythm.

More about Michael

More about Jeff

More about Drosophila

 

Sebastian Kadener Returns to Brandeis as Associate Professor

Sebastian Kadener

From 2002 to 2008, Sebastian Kadener was a postdoc working in the Michael Rosbash laboratory. He is returning to Brandeis as an Associate Professor of Biology. Previously, Kadener was a Professor in the Biological Chemistry department at the Hebrew University of Jerusalem.

The Kadener laboratory studies how molecular processes in the brain determines behavior with a special emphasis on RNA metabolism. Additionally, they study the role of circular RNAs (circRNAs) at the molecular and neural levels as well as the mechanisms underlying circadian clocks.

Kadener’s paper, “Translation of CircRNAs”, appeared in Molecular Cell in April 2017. It was reviewed in Nature Reviews Genetics and Science Daily.

SciFest VII Wraps Up Summer 2017 Undergraduate Research Session

The Brandeis University Division of Science held its annual undergraduate research poster session SciFest VII on August 3, 2017, as more than one hundred student researchers presented summer’s (or last year’s) worth of independent research. We had a great audience of grad students and postdocs (many of whom were mentors), faculty, proud parents, friends, and senior administrators.

More pictures and abstract books are available at the SciFest site.

SciFest VII by numbers

Protected by Akismet
Blog with WordPress

Welcome Guest | Login (Brandeis Members Only)