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graduationCongratulations!

 

The Junior Scientists' Publication Award Committee of the Max Planck Institute of Biochemistry has selected this year's award winners.

22 awardees with 19 publications have been awarded the JSPA this year. The celebration took place online and some of the young scientists presented their exciting research results during the minisyposium.

We are very proud that 10 ou of 22 awardees are or have been IMPRS-LS graduate students. We are very proud of you!

 


 

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Amaro, D., Ferreiro, D.N., Grothe, B., and Pecka, M.
Curr Biol, 2021, online ahead of print.
doi: 10.1016/j.cub.2021.06.025

Source identity shapes spatial preference in primary auditory cortex during active navigation

Information about the position of sensory objects and identifying their concurrent behavioral relevance is vital to navigate the environment. In the auditory system, spatial information is computed in the brain based on the position of the sound source relative to the observer and thus assumed to be egocentric throughout the auditory pathway. This assumption is largely based on studies conducted in either anesthetized or head-fixed and passively listening animals, thus lacking self-motion and selective listening. Yet these factors are fundamental components of natural sensing that may crucially impact the nature of spatial coding and sensory object representation. How individual objects are neuronally represented during unrestricted self-motion and active sensing remains mostly unexplored. Here, we trained gerbils on a behavioral foraging paradigm that required localization and identification of sound sources during free navigation. Chronic tetrode recordings in primary auditory cortex during task performance revealed previously unreported sensory object representations. Strikingly, the egocentric angle preference of the majority of spatially sensitive neurons changed significantly depending on the task-specific identity (outcome association) of the sound source. Spatial tuning also exhibited large temporal complexity. Moreover, we encountered egocentrically untuned neurons whose response magnitude differed between source identities. Using a neural network decoder, we show that, together, these neuronal response ensembles provide spatiotemporally co-existent information about both the egocentric location and the identity of individual sensory objects during self-motion, revealing a novel cortical computation principle for naturalistic sensing.

 


 

graduation

Congratulations on your PhD!

 

Andreas-David Brunner


True single-cell proteomics using advanced ion mobility mass spectrometry


RG: Matthias Mann

 


 

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Sinitcyn, P.#, Hamzeiy, H.#, Salinas Soto, F., Itzhak, D., McCarthy, F., Wichmann, C., Steger, M., Ohmayer, U., Distler, U., Kaspar-Schoenefeld, S., Prianichnikov, N., Yılmaz, Ş., Rudolph, J.D., Tenzer, S., Perez-Riverol, Y., Nagaraj, N., Humphrey, S.J., and Cox, J.
#equal contribution
Nat Biotechnol, 2021, online ahead of print.
doi: 10.1038/s41587-021-00968-7

MaxDIA enables library-based and library-free data-independent acquisition proteomics

MaxDIA is a software platform for analyzing data-independent acquisition (DIA) proteomics data within the MaxQuant software environment. Using spectral libraries, MaxDIA achieves deep proteome coverage with substantially better coefficients of variation in protein quantification than other software. MaxDIA is equipped with accurate false discovery rate (FDR) estimates on both library-to-DIA match and protein levels, including when using whole-proteome predicted spectral libraries. This is the foundation of discovery DIA-hypothesis-free analysis of DIA samples without library and with reliable FDR control. MaxDIA performs three- or four-dimensional feature detection of fragment data, and scoring of matches is augmented by machine learning on the features of an identification. MaxDIA's bootstrap DIA workflow performs multiple rounds of matching with increasing quality of recalibration and stringency of matching to the library. Combining MaxDIA with two new technologies-BoxCar acquisition and trapped ion mobility spectrometry-both lead to deep and accurate proteome quantification.

 


 

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Eckl, E.M., Ziegemann, O., Krumwiede, L., Fessler, E., and Jae, L.T.
Cell Mol Life Sci, 2021, online ahead of print.
doi: 10.1007/s00018-021-03887-7

Sensing, signaling and surviving mitochondrial stress

Mitochondrial fidelity is a key determinant of longevity and was found to be perturbed in a multitude of disease contexts ranging from neurodegeneration to heart failure. Tight homeostatic control of the mitochondrial proteome is a crucial aspect of mitochondrial function, which is severely complicated by the evolutionary origin and resulting peculiarities of the organelle. This is, on one hand, reflected by a range of basal quality control factors such as mitochondria-resident chaperones and proteases, that assist in import and folding of precursors as well as removal of aggregated proteins. On the other hand, stress causes the activation of several additional mechanisms that counteract any damage that may threaten mitochondrial function. Countermeasures depend on the location and intensity of the stress and on a range of factors that are equipped to sense and signal the nature of the encountered perturbation. Defective mitochondrial import activates mechanisms that combat the accumulation of precursors in the cytosol and the import pore. To resolve proteotoxic stress in the organelle interior, mitochondria depend on nuclear transcriptional programs, such as the mitochondrial unfolded protein response and the integrated stress response. If organelle damage is too severe, mitochondria signal for their own destruction in a process termed mitophagy, thereby preventing further harm to the mitochondrial network and allowing the cell to salvage their biological building blocks. Here, we provide an overview of how different types and intensities of stress activate distinct pathways aimed at preserving mitochondrial fidelity.

 


 

graduation

Congratulations on your PhD!

 

Valerie Goh


Unravelling the functional interconnections among the mitochondrial uniporter complex components

RG: Fabiana Perocchi

 


 

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Bauer, J., Weiler, S., Fernholz, M.H.P., Laubender, D., Scheuss, V., Hübener, M., Bonhoeffer, T., and Rose, T.
(IMPRS-LS students are in bold)
Neuron, 2021, online ahead of print.
doi: 10.1016/j.neuron.2021.05.036

Limited functional convergence of eye-specific inputs in the retinogeniculate pathway of the mouse

Segregation of retinal ganglion cell (RGC) axons by type and eye of origin is considered a hallmark of dorsal lateral geniculate nucleus (dLGN) structure. However, recent anatomical studies have shown that neurons in mouse dLGN receive input from multiple RGC types of both retinae. Whether convergent input leads to relevant functional interactions is unclear. We studied functional eye-specific retinogeniculate convergence using dual-color optogenetics in vitro. dLGN neurons were strongly dominated by input from one eye. Most neurons received detectable input from the non-dominant eye, but this input was weak, with a prominently reduced AMPAR:NMDAR ratio. Consistent with this, only a small fraction of thalamocortical neurons was binocular in vivo across visual stimuli and cortical projection layers. Anatomical overlap between RGC axons and dLGN neuron dendrites alone did not explain the strong bias toward monocularity. We conclude that functional eye-specific input selection and refinement limit convergent interactions in dLGN, favoring monocularity.

 


 

graduation

Congratulations on your PhD!

 

Hui-Lan Huang


Deciphering the role of the sugar-induced transcription factor, Mondo in Drosophila Melanogaster

RG: Andreas Ladurner

 


 

For her insights into the neuronal mechanism of motion perception, Dr. Yunmin Wu is awarded the Otto Hahn Medal. The scientist at the Max Planck Institute of Neurobiology decoded the neuronal basis of an optical illusion in the zebrafish brain. For her achievements, she now receives the 7500€ prize of the Max Planck Society, which is awarded annually for excellent scientific achievements by young talents.

It all started with a cat video. After Yunmin Wu saw that optical illusions also work in animals, the doctoral student came up with the idea for her own research. She would trigger the motion aftereffect, also called the "waterfall illusion," in the tiny zebrafish larvae she was studying in Herwig Baier's department. In this way, she sought to better understand what actually happens in the brain when movements are perceived.

In the brain, several thousand neurons process movements and their direction. Using the waterfall illusion, Yunmin Wu was able to show that only a handful of cells out of this large number of neurons are necessary and sufficient for motion vision. "If we ask the right questions with the right tools, we are able to see very interesting things that we didn't know before," Yunmin Wu affirms. "It's the idea behind my project that I'm proud of. I'm very pleased that this is being recognized by the Max Planck Society and the award committee."

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The Royal Society has elected Elena Conti, director at the Max Planck Institute of Biochemistry, as new Foreign Member. Founded in 1660, the United Kingdom’s National Academy of Science is a prestigious community committed to the highest quality of science. By electing Elena Conti as new member, the Society recognizes her outstanding work in the fields of RNA and structural biology. The admission ceremony is planned to take place in summer 2021, contingent of the pandemic situation.

About the new elected Foreign Member

In cells with a nucleus, ribonucleic acid, RNA, connects genetic information on DNA level in the nucleus with protein production in the cytoplasm. How is RNA transported from the nucleus into cell cytoplasm and how is RNA degraded? Which molecules and processes are necessary? Elena Conti, head of department of “Cellular Structural Biology” at the Max Planck Institute of Biochemistry, has been working on these research questions for many years.

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