Events

Prof. Dr. Georg Nagel from the Institute of Physiology – Neurophysiology, University Würzburg will talk about “Light-sensitive Proteins from Microbes for non-invasive Light-manipulation of Animals and Plants”

Abstract

The discovery of Channelrhodopsins (ChR) and their characterization by heterologous expression in 2002/2003 paved the way to highly specific light-manipulation of cells or animals, a technique now called optogenetics. More channelrhodopsins from different organisms were found and genetic engineering generated a further variety so that many different optogenetic tools are available now. Light-activated ion pumps (microbial rhodopsins, like ChR) further expanded the optogenetic toolbox. Already in 2007 we established that also a microbial flavoprotein, a photo-activated adenylyl cyclase (PAC), is a useful tool to increase cAMP in animal cells or live Drosophila flies, simply by blue light illumination. By genetic engineering we further improved a PAC to a membrane-bound adenylyl cyclase with no activity under red light or in the dark. Similar improvements could be demonstrated for a natural soluble PAC.
In many animal cells the necessary cofactor for rhodopsins – i.e. retinal (Vitamin A) – is already present or may be easily provided by feeding which is not the case in land plants. To enable “green optogenetics” with rhodopsins we first established growth under non-activating red light and generated transgene tobacco plants which produced endogenous retinal. After several rounds of modification, microbial rhodopsins could then be functionally expressed in the plasma membrane of different plant cells. Light-activation of these rhodopsins now enables novel approaches to study plant cellular signalling.

Chairs: Tobias Moser and Thomas Mager

Poster of the talk:

Viviana Grandinaru, PhD from the California Institute of Technology, Pasadena, USA will talk about

“Getting across barriers: Gene delivery across the blood-brain barrier for precise and minimally-invasive study and repair of nervous systems”.

Abstract

Protein engineering and data science have helped overcome challenges in optogenetics and gene delivery, with microbial opsins tolerated by mammalian cells and viral capsids that cross the blood–brain barrier. These tools are applied to neurodevelopmental and neurodegenerative disorders, for e.g. to understand circuits underlying locomotion and sleep for Parkinson’s disease. By understanding how engineered capsids work and leveraging them as vehicles for targeted gene delivery via the vasculature, we are now closer to precise noninvasive study and repair of nervous systems.

Host: Ursula Fünfschilling

Poster of the talk

Prof. Dr. Jutta Engel from the Center for Integrative Physiology and Molecular Medicine (CIPMM) at the Saarland University will talk about “Ca²⁺ channel complexes in cochlear inner hair cells und further up the auditory pathway”.

Abstract
Voltage-gated Ca²⁺ channels (VGCC) are essential for chemical signal transmission in sensory cells and in neurons. In inner hair cells (IHC), sound-evoked receptor potentials open Ca_v1.3 Ca²⁺ channels that cause Ca²⁺ influx and exocytosis. However, VGCCs are not only crucial for synaptic transmission but also for developmental processes and for synaptic plasticity. Ten genes of pore-forming α₁ subunits as well as 4 genes of auxiliary β- and α₂δ subunits lead to a large functional variety of channel complexes.
I will focus on the composition and functions of IHC Ca_v1.3 channel complexes in development, in mature function and in the maintenance of the mature IHC phenotype. Further, I will report on the role of auxiliary α₂δ3 subunits of high voltage-activated Ca_v2.1 VGGCs for the ultrafast and precise synaptic transmission in spiral ganglion neurons, the auditory brainstem, and midbrain. α₂δ3 is encoded by Cacna2d3, which has been identified as risk gene for autism spectrum disorders in humans. Mice lacking Cacna2d3, which show impaired processing of amplitude-modulated tones at the level of the inferior colliculus and in behavior, present a model for an auditory processing disorder.

Host: Prof. Dr. Tobias Moser

Poster of the talk

The Hertha Sponer College Lecture Series is addressed to interested students, PhD candidates, postdocs, and PIs. The overall idea is to fundamentally explain research by providing an overview about the general aims of the six MBExC Research Alliances with special focus on the specific techniques that are developed and applied. The lectures take place on Tuesdays at 5 pm within the semester term, and are offered by MBExC PIs. Subsequent to lecture and discussion, Hertha Sponer College members have the opportunity to “Meet-the-PI” and each other for asking more specific or general questions, networking and socializing.

Session:  “Calcium triggered membrane fusion”

For log-in information please contact: ed.negnitteog-inu.dem@darnoc.ekieh