A major challenge of evolutionary biology is to understand which genes control ecologically relevant traits and how variation at these genes affects the fitness of organisms in their natural environment. In order to achieve this goal, a large degree of integration between different disciplines is required. In this project I propose to thoroughly analyze and dissect an adaptive trait, seed color variation, from its role in ecological interactions to its molecular basis. In desert sunflowers, seed color often matches the color of the soil, suggesting the presence of a camouflage mechanism reducing predation. This is an extremely tractable system for ecological studies in which genetic, phenotypic and environmental factors can be manipulated independently. Together with the ample availability of genomic resources for sunflower and the generally simple genetic basis of color polymorphism in plants, this makes seed camouflage an ideal system to ask general questions about the evolution and genetic bases of adaptation. I will use a combination of field experiments, landscape resequencing, QTL mapping and molecular biology to characterize the genes controlling seed color variation in wild sunflower and its effects on predator preferences and plant fitness. This information will be complemented by association studies aimed at identifying the genetic bases of seed color variation in cultivated sunflower. Together, these data will be used to understand the evolutionary dynamics of the identified genes in natural and cultivated environments. This multi-disciplinary approach will enable a more comprehensive understanding of the genetic mechanisms underlying adaptive processes.

Lysine (K) acetylation was first discovered on histones over four decades ago. Although histones have been the primary focus of acetylation research, recent studies showed that many proteins, also outside of the nucleus and implicated in a diverse set of cellular functions, could be acetylated. The specific role of acetylation and how this posttranslational modification is regulated is largely unknown. Circadian rhythms control physiological and metabolic processes. The core circadian protein CLOCK has acetyltransferase activity counterbalanced by the deacetylase SIRT1. SIRT1 activity is regulated in a circadian manner and also the levels of its cofactor, NAD+, oscillate, suggesting a link between cyclic rhythms and energy metabolism. In this project I propose to study the circadian acetylome of neocortex in wt and tissue-specific sirt1 -/- mice, through liquid-chromatography tandem mass spectrometry (LC-MS/MS) analysis and to compare it with liver acetylome. SIRT1 is involved in diverse brain functions (ageing, neurodegeneration, learning and memory) and it is implicated in regulation of different metabolic pathways in the liver by deacetylating key enzymes implicated in glucose and lipid metabolism. By analysing the circadian acetylome in liver and cerebral cortex, I expect to identify which proteins are characterized by oscillation in lysine acetylation and the function and regulation of this rhythmic modification.

The transcriptional induction of many biosynthetic pathways follows a defined temporal order, termed “just-in-time” (JIT) activation, where upstream acting enzymes are activated first, followed by downstream enzymes. Mathematical models predict that JIT activation is beneficial in unstable environments, but is suboptimal when the environment is constant. This suggests that the transcriptional regulatory networks controlling metabolic genes face an evolutionary trade-off between optimality under stable conditions and their ability to adapt to environmental changes. This prediction has, however, never been experimentally verified, nor has it been studied how JIT activation emerges during evolution. The proposed project will address this by quantitatively assaying the evolutionary cost and benefit of the JIT activation of amino acid (AA) synthesis pathways in E. coli.
I will genetically engineer strains that activate all enzymes of a pathway at once and compare their growth with wild-type JIT activation. If mathematical models hold true JIT activation will be beneficial specifically when the concentration of externally provided AAs is fluctuating. To examine the evolutionary plasticity of the regulatory network controlling JIT activation, I will evolve the engineered all-at-once strain under stable or fluctuating laboratory conditions. By characterizing the evolved strains, as well as evolutionary intermediates, I will study how regulatory networks controlling JIT activation arise during evolution and whether there is a predictable order of evolutionary adaptations. I will thereby study how environmental fluctuations influence the evolution of metabolic pathway control.

Within the visual system, directional selectivity (DS) is a well-established characteristic of many retinal and cortical neurons. Remarkably, there is no direct evidence indicating that retinal DS is responsible for cortical DS, and it is widely held that cortical DS is generated within the cortex from non-DS inputs. Nonetheless, as recent evidence has revealed that retinal ON-OFF DS ganglion cells (DSGCs) project to subcortical pathways, I propose to test whether some forms of cortical DS responses are driven by retinal DS outputs. To test this, I will alter activity of retinal DS neurons and monitor for changes in cortical DS. To modulate retinal DS neurons, I will make genetic manipulations to a mouse line in which Cre recombinase is selectively expressed in ON-OFF DSGCs, allowing me to ectopically express light activated ion channels (channelrhodopsins) in these neurons. To measure signals in visual cortex, I will use a state-of-the-art in-vivo 2-photon calcium imaging system to monitor cortical signals while I manipulate activity of retinal DS neurons. Finally, to show that these manipulations are relevant to behaviour, I will put mice into a virtual reality system, and monitor for changes in visually guided behaviour while I modulate activity of retinal DS neurons. The findings from this work will provide important insights into the detailed workings of the visual system, and reveal to an unprecedented level of detail how the cortex processes retinal inputs.

DEAD-box proteins are highly conserved enzymes carrying out fundamental functions in gene expression. They utilize ATP to unwind short double-stranded RNAs or to remodel ribonucleoprotein particles. Mss116 is a yeast mitochondrial DEAD-box protein required for efficient splicing of group II introns in vivo, rendering it a crucial component of the mitochondrial gene expression machinery. The precise mechanisms of Mss116 function are yet to be determined. Furthermore, the important question if Mss116 and DEAD-box proteins in general are able to translocate on RNA remains insufficiently answered, so far. Single-molecule methods are well-suited to approach such mechanistic questions.

Starting from unpublished data from the Ha lab indicating that Mss116 may indeed move on single-stranded RNA, I propose a detailed and elaborate single-molecule study addressing the precise mechanisms of Mss116 function. The first goal is to demonstrate, for the first time, translocation of Mss116 on single-stranded RNA using a "fleezer", a cutting-edge single-molecule instrument combining fluorescence detection with an optical tweezer that allows the observation of single fluorescence-labeled protein molecules in a space and time resolved manner at high resolution. Further, I aim to monitor Mss116 function on an endogenous substrate, the group II intron aI5gamma, allowing for detailed mechanistic insights of how Mss116 facilitates the folding process of a group II intron. Together with studies of mutant proteins and related DEAD-box proteins this study aims to provide highly significant mechanistic insight into the function of DEAD-box proteins in general.

What can a honeybee ‘understand’ with a miniature brain containing only 960,000 neurons? What visual features can she detect innately and how complex are the visual categories she can learn in her lifetime? Despite the wealth of experimental data on bee learning behaviour, there is a remarkable disagreement in this question, due to the general lack of understanding of the neural computations underpinning visual cognition in insects.
In this project I propose to generate and test computer models of the neural basis of visual category learning in bees using advanced techniques from computational neuroscience. I will (1) integrate the currently available information on the neurobiological background of bee vision in a computer simulation; (2) use in silico evolution to find possible neural architectures that satisfy the neurobiological constraints and are consistent with behavioural data; (3) use my model to design experiments that can maximally discriminate between competing hypotheses.
Bees in particular offer an excellent model system for such studies, as their behaviour and cognitive abilities, as well as the neurobiology of their sensory systems, are extensively studied. It is not surprising therefore that bees have become the model for studying seemingly advanced cognition with minimal neuronal hardware, and therefore a benchmark for all comparative cognition research. Thus, the implications of the proposed project will not only concern insect psychophysics, but will alter our understanding of computer vision, neuroscience and behavioural ecology.

Attention is well known to enhance sensory processing in the cortex. There is strong evidence that such effects are partly mediated by the release of acetylcholine (ACh) by cholinergic neurons arising in the basal forebrain (BF) and projecting throughout the cortex. Direct stimulation of the BF has been shown to improve sensory processing. However, what neural mechanisms control the BF activity and how it is influenced by the state and expectations of the behaving animal are still largely unknown. Here, I aim to unravel mechanisms that translate reward expectations into enhanced sensory processing and behavioral performance.

Due to the availability of new molecular and genetic tools that allow recordings and manipulation of specific cell types, all the experiments will be performed with mice. First, I will develop a visual discrimination task with varying reward sizes to test how visual cortical processing and the animal’s performance depend on the expected reward. Second, I will perform cell-type specific recordings from cholinergic and GABAergic neurons in the BF to determine whether and how these cells encode the expected reward size. Finally, I will employ mono-synaptically restricted, viral tracing techniques to record from dopaminergic neurons in the ventral tegmental area (VTA) that project to the BF and test whether these projections transmit information about the expected reward size. Manipulation of projections from the VTA to the BF will allow me to disentangle their impact on sensory processing and behavior. With this approach I will unravel the specific role of VTA neurons projecting to the BF in the reward dependent top-down control of visual processing.

Meiosis is a specialised form of eukaryotic cell division that diploid cells undergo to generate haploid gametes. Central to meiosis is a set of processes involving the physical interaction of homologous chromosomes at sites of programmed DNA double-strand breaks. The physically joined chromosomes are resolved in a manner that either results in the reciprocal exchange of DNA between the homologous chromosomes (a crossover product) or not (a non-crossover product). Crossover products are necessary to create genetic diversity and prevent the mis-segregation of chromosomes, a source of infertility and birth defects in humans. Both the number and physical distribution of crossover products along chromosomes are tightly regulated. The mechanism of this regulation is unknown. However, it has been shown that the SUMO E3 ligase protein Zip3 binds to both the precursors of crossovers and non-crossovers at early stages of meiosis, and specifically to the sites of crossovers at late stages of meiosis. I propose to exploit this for development of a method for enriching for chromatin designated for both crossover and non-crossover formation and for chromatin marked for crossover formation specifically. Proteomic analysis of these chromatin samples will provide new insight into crossover regulation by identifying key players that will be verified by classical genetic and molecular biology approaches.

Plants are sessile organisms and highly dependent on light as their energy source. This means competing vegetation is an enormous threat for the plant´s survival. The change in light quality produced by surrounding plants is sensed by the phytochrome family of photoreceptors. Canopy shade inactivates phytochromes and thus induces an escape program to improve the plant´s access to light. If this strategy fails flowering is accelerated to enhance the chance for reproductive success. At the same time, this early flowering is accompanied by reduced biomass and seed yield. However, it is very poorly understood how premature flowering is induced by canopy shade and repressed by phytochrome activity. Some downstream genes necessary for acceleration of flowering in canopy shade are already known, but it is not understood how they are regulated by phytochrome signaling. Furthermore, these genes only execute a subset of the shade-induced flowering pathway.
My aim is to investigate the mechanisms regulating flowering through phytochromes and canopy shade using two candidate gene approaches to analyze different signaling levels. Furthermore, as an unbiased approach, I will conduct a forward genetic screen to identify novel regulators of the phytochrome-dependent flowering. The combination of genetic, molecular biological and biochemical tools will allow me to examine until now neglected levels of this signaling pathway and aims to further our understanding of this essential response that controls the plants´ fitness.

Adult neural stem cells reside in discrete neurogenic niches in the adult mammalian brain and generate newborn neurons throughout life. Neural stem cells can shuttle between mitotically active or quiescent states. Quiescence may play an essential role in preserving the proliferative capacity of stem cells and limiting the accumulation of genomic mutations by minimizing rounds of DNA synthesis. It is therefore important to understand the mechanisms regulating quiescence of neural stem cells in vivo. Recent studies showed that phosphorylation of the histone variant H2AX, which facilitates the repair of DNA double strand breaks, restricts proliferation of embryonic stem cells and other stem cells. I hypothesize that niche factor-induced active phosphorylated H2AX (γ-H2AX) in nucleosomes maintains the quiescence of adult neural stem cells via an epigenetic mechanism. I will determine the expression of γ-H2AX in different neural stem cell lineages by immunohistology. Clonal analysis will be performed in individual adult neural stem cells with conditional deletion of H2AX to uncover the role of H2AX in controlling the quiescence, self-renewal mode and fate choice of neural stem cells in the adult mouse brain in vivo. I will further examine how GABA, a key niche factor, regulates H2AX activity via optogenetic manipulation of specific interneuron subtype and genetic manipulation of specific GABAA receptor. Moreover, I will investigate the role of H2AX in epigenetic regulation of gene expression with chromatin immunoprecipitation sequencing (Chip-seq) to map the γ-H2AX-occupied DNA sequences and RNA-seq analysis of gene expression in quiescent adult neural stem cells.

This proposal focuses on understanding fundamental properties of actin-like MreB cytoskeletal filaments in prokaryotes. How is the MreB filament remodeled during the cell cycle and differentiation? What are the specific changes of MreB organization and dynamics that allow different growth rate under varying environments? What are the molecular mechanisms and regulators by which the cytoskeleton mediates cell envelope biogenesis and possibly establish other spatial organization within cells? Due to the large number of players involved and functional redundancy in the system, the answers to these basic biological questions remain elusive. We propose to address these questions in the model gram-positive bacterium Bacillus subtilis by employing an interdisciplinary approach combining genetics, genomics, biochemistry and advanced imaging (e.g. single molecule microscopy). The ease with which biochemical and genetic analysis, as well as advanced imaging can be carried out in B. subtilis makes it an ideal system to uncover the molecular mechanism of spatial and temporal regulation of MreB dynamics and organization. We propose to complement these by developing a microfluidic device and computational imaging analysis tools to : 1) Characterize the subcellular patterns of MreB filaments throughout cell cycle with high temporal and spatial resolution in live single cells. 2) Identify components of the regulatory network responsible for modulating MreB assembly. 3) Determine how the complex web of interactions amongst the factors involved in MreB assembly and biogenesis of cell envelope dictate cell elongation and division in different environments.

The neocortex is organized into neural circuits that perform distinct computations, from sensory processing and motor control to memory, learning and language. In these circuits, excitatory and inhibitory neurons are extensively interconnected and the balance between their activities is tightly regulated. Dynamic modulation of cortical states, associated with rapid changes to the excitation/inhibition (E/I) balance, is thought to allow the brain to rapidly respond to changes in behavioral demands. Yet, little is known regarding the mechanisms responsible for rapid modulation of the E/I balance during behavior. Chronic changes to the E/I balance, occurring during early development, were proposed to dramatically alter the structure and function of cortical circuits and give rise to cognitive and behavioral impairment associated with neuropsychiatric disorders. Yet, the impact of such changes on cortical organization has not been directly tested. This research proposal is aimed at elucidating the mechanisms responsible for dynamic modulation of the E/I balance in the prefrontal cortex, a cortical region involved in working memory, attention and goal-directed behavior. Using a novel opto-physiological recording system, we will study the rapid behavioral state-dependent dynamics of prefrontal E/I balance and its regulation by naturally occurring neuromodulation. We will further examine the changes in cortical circuit organization and function resulting from chronic alterations in the E/I balance. These projects address fundamental aspects of cortical function and will be valuable in determining the causal role of E/I balance changes in neurodevelopmental disorders.

The kinetics of neurotransmitter release determines the duration of the postsynaptic response, and therefore has major implications on synaptic strength, circuit development, and cognition. Recent studies also suggest that mutations altering the kinetics of presynaptic release can confer risk for autism spectrum disorders (ASD). Here I propose a comprehensive set of genetic, cell biological, and biophysical experiments to define mechanisms regulating the kinetics or neurotransmitter release at synapses.
Synaptic transmission comprises fast and slow modes of neurotransmitter release, which evoke post-synaptic responses with correspondingly different durations. However, relatively little is known about the molecules and pathways that regulate each form of release. Previous work suggests that the syntaxin-binding protein Tomosyn/TOM-1 might be a selective inhibitor of slow release. Therefore, I propose three Aims for this project, using C. elegans as a model system: 1) I will test several candidate genes for their ability to regulate TOM-1 function; 2) I will analyse how each of these factors regulate TOM-1 activity, and test for four possible mechanisms: altered binding of TOM-1 to SVs, altered dissociation of TOM-1 from SVs, changes in formation of TOM-1 SNARE complexes, and altered TOM-1 expression and synaptic abundance; 3) I will perform a genetic screen to identify novel TOM-1 regulators, and analyse how they inhibit TOM-1 activity as described in Aim 2.
These experiments will provide new insights into the cell biological mechanisms regulating synaptic transmission and plasticity, as well as mechanisms underlying the changes in cognition and development in ASD.

The lack of information on the physiological basis of the neuronal control of mood severely limits the study of mood disorders. Recent evidence suggests that the circadian (~24-hr) timekeeping system in mammals can trigger mania or depression. Circadian mistiming has also been shown in animals or patients showing symptoms of mania or depression. Here, we study how the central circadian pacemaker, located in the suprachiasmatic nucleus (SCN) of the hypothalamus, controls and is regulated by mood. Functionally, the SCN appears homogeneous and most SCN neurons contain the inhibitory neurotransmitter GABA. In reality, however, SCN cells display heterogeneity; many, but not all, SCN neurons contain the intracellular molecular clock and some SCN neurons can be further distinguished by their neuropeptide content. Further, we recently showed that neurons in the SCN show a wide variety of electrical states, from hyperpolarization during the night to a novel depolarized states during the day. Consequently, neurons and subregions in the SCN vary in their key cellular and molecular properties. Here, we use behavioral, genetic, and pharmacological models of mania and depression and determine alterations in SCN timekeeping at molecular, cellular, and network levels. Experimental results will be incorporated into detailed mathematical models, which will then predict future experiments. This will identify which network states of the SCN (or states of subpopulations of SCN neurons) trigger manic or depressive symptoms. We will also determine how mutations in key components of the intracellular circadian clock are linked with mood and lead to changes in the overall state of the SCN. Finally, we will determine if desynchronized timekeeping among SCN neurons or pathological electrical activity, triggers mood phenotypes. In addition to expertise in circadian timekeeping shared by all, our team includes a modeling group at the University of Michigan in the United States, an electrophysiology group at the University of Manchester in the United Kingdom, and a group that studies both animal models for neurological disorders at Hiroshima University in Japan.

Most proteins produced by any genome are processed during their synthesis on ribosomes, including cleavage of the N-terminal methionine, N-terminal acetylation, transport to a membrane channel or association with molecular chaperones for folding. These processing steps are usually specific for the type of protein made and often crucial for cell survival, as their occurrence affects the localization, stability and activity of proteins. These different co-translational activities on nascent chains have to be highly coordinated temporally and spatially to ensure the functionality of the translatome. Most studies have focused on the specificity of processing factors themselves including modifying enzymes, chaperones or transport factors (abbreviated hereafter collectively as NAFs, for Nascent polypeptide-Associated Factors) and little attention has been bestowed on the ribosome as contributing to specificity and coordination. However, recent work suggests the ribosome may have a sensing mechanism that signals the type of the emerging nascent peptide from the interior of the exit tunnel to the exterior of the ribosome for co-translational recruitment of appropriate NAFs. The mechanisms of ribosomal sensing and factor recruitment, however, are unknown.
Here we propose to employ an interdisciplinary approach to analyze how signalling by polypeptides inside the eukaryotic ribosomal tunnel is transmitted to the ribosome exterior for recruitment of the appropriate NAFs. Together, our integrated programme will allow unprecedented insights into how the emerging nascent polypeptide chain is sensed by the ribosome and how it signals to recruit different enzymes, chaperones and transport factors to the ribosome exit tunnel in readiness for their immediate, co-translational modification, folding or transport.

During their life, cells of the immune system experience a large range of mechanical stimuli. These range from shear stresses encountered in blood flow and lymph nodes to irregular topographical cues of extracellular matrix fibers and changes in tension during movement from capillaries to tissue. The process of converting physical cues into biochemical signals and integrating these signals into a cellular response is referred to as mechanotransduction and plays a crucial role in health and disease. To sense the physical cues of its surrounding, cells have specialized mechanosencing proteins arranged on the cellular membrane. While it is accepted that the mechano-chemical signal conversion involves force-induced changes of protein functions, it remains a major mystery how physical and biochemical factors are coupled and integrated to enable mechanical sensing.
The overall goal of this project is to provide mechanistic insight into the role of mechanical stimuli in the regulation of cellular signaling. Specifically, we will determine the influence of applied mechanical forces on the spatial organization of primary mechanosensors called integrins and how these changes alter signaling processes. Thus, our project will explore mechanosensing, mechanotransduction and mechanoresponses. We will define the effects of force and geometry sensing on cellular responses of two types of immune cells, monocytes and dendritic cells.
To achieve this goal, we have assembled a multidisciplinary team that not only brings together expertise in the two cell types, but also integrates biophysics with cell biology and immunology. To address the question of how stress alters membrane organization and signaling at the molecular level, we will use cutting-edge biophysical tools recently developed by team members, including superresolution imaging and nanospectroscopy, hyperspectral microscopy and tailored-made microdevices for mechanical manipulation. The concept that mechanical forces play a role in altering the organization of proteins in the cellular membrane and consequently signal transduction is new in the mechanobiology field. Therefore, our project will provide a significant conceptual advance in our understanding of how the cell interprets external forces that it encounters in its native environment.

Malaria is one of the most important parasitic infections of humans. Every year more than 250 million people contract malaria resulting in 1 million deaths, mostly African children, and Plasmodium falciparum is responsible for the most severe disease. The key to successful infection in humans is the parasite’s ability to evade the immune system by living within host cells. First, the parasite invades hepatocytes and approximately one week later emerges to infect erythrocytes.
The liver-stage of malaria is clinically silent; however, when erythrocytes are infected, the parasite exports several hundred proteins beyond the vacuole membrane to remodel the cell. Erythrocyte remodeling is responsible for the devastating manifestations of falciparum malaria.
During the liver-stage parasites grow in hepatocytes within a vacuole without eliciting an immune response. Intracellular development involves blocking host cell apoptosis; however, genetically modified parasites are often killed in a T cell-dependent manner that provides protective immunity. Thus, studies focused on the liver-stage of malaria have profound significance and may guide the development of new antimalarials or a vaccine.
Here, we aim to determine if the protein export pathway used by P. falciparum for intraerythrocytic development is used in the liver-stage of infection and propose to dissect the intracellular dynamics of liver-stage malaria form both the parasite and host perspectives.

How activity of individual neurons and neural circuits governs coordinated adaptive behaviour is a fundamental biological question. Classical studies highlighted an unidentified “brain orchestrator” within the hypothalamus, which is evolutionally conserved and crucial for the emergence of coherent innate and goal-oriented behaviors. Yet until recently, advances in this field have been hampered by the heterogeneity and complex wiring of hypothalamic neural circuits, along with the lack of specific tools to manipulate defined neuronal populations with high temporal resolution. The overall goal of our proposal is to reveal and decode neural dynamics of genetically-defined hypothalamic circuits and the neurobiological mechanisms of the initiation and coordination of multiple vital functions, including food intake and sleep. Here, we propose to first identify the activity and emergent interactions within and between classes of optogenetically-defined neurons in the hypothalamus across innate behaviors and vigilance states using high-density electrophysiological recordings in freely behaving animals. Second, we will assess the sufficiency and necessity of those neuronal circuits in regulation of feeding and sleep-wake states during homeostatic challenges using in vivo optogenetics and customized biosensors. Third, we will study the cellular mechanisms underlying intra- and extra-hypothalamic network interactions using calcium imaging, two-photon microscopy and in vivo electrophysiology. Clear functional readouts attributed to hypothalamic activity will enable us to address physiological mechanisms from the perspective of real-time operation of hypothalamic networks and their targets. In particular, we will fundamental questions, including: How is firing in one class of neurons influenced by local circuit environment and how is this translated into global changes in brain state and behavior? What is the discharge code for the release of different transmitters/modulators from specific axons and how does it shape their functional output? What molecular and physiological features underlie target-specific functions of widely-projecting hypothalamic neurons? Our research plan comprises a novel combination of technologies (genetic bioengineering, behavioural assays, in vivo and in vitro electrophysiology, optical imaging and optical modulation) made possible through the new collaboration between the three participants. Through this approach, we aim to unravel functional organization into the major brain-body interface and thus gain insights into neural basis of adaptive behaviour and healthy, coordinated brain function.

Emotions are the key to understanding why some memories stay vivid for years while others fade with time. The role of the “so called” neuromodulatory systems in the modulation of emotional memory has been gaining considerable research attention. We have recently shown that endocannabinoid-glucocorticoid interactions modulate emotional memory. The aim of this proposal is to unveil the fate of emotional memory processing in rodents by: 1) defining the precise role of the endocannabinoid system in the modulation of emotional memory; 2) unravelling how different neural systems in multiple brain areas coordinate themselves as one in the regulation of this process. Indeed, emotional memory processing involves a coordination of multiple neurotransmitter systems in different brain areas; however, the precise mechanisms by which this “neural orchestra” shapes memory function are still unknown, mainly because the conventional pharmacological approaches currently available do not allow to simultaneously study all the neural systems that, at a given time, regulate memory function in subjects performing a cognitive task .
Developing novel analysis models that may eventually overcome the limits of the methodologies currently available and provide responses to questions that cannot yet be answered is an essential step in cognitive neuroscience research.
The current challenge of neuroscience research in this field requires indeed to develop novel analysis models that may help to understand the dynamics of neurotransmitter release in different brain areas, the chemical mechanisms involved, and their participation during different memory processes. Thus, the possibility of correlating behavior with changes in the extracellular level of neurotransmitters in different brain regions would be a great advantage in the study of memory processing.
To achieve this critical important and ambitious goal, we will use a revolutionary interdisciplinary approach combining expertise in behavioural neuroscience and in nanotechnology.
We strongly believe that by forging an unconventional collaboration that joints highly disparate expertise in the field of neurobiology and nanotechnology, our proposed project can open up completely new horizon in neuroscience research.

To date, it is still an enigma how nerve cells can sense their own lengths, especially over the remarkable intracellular distances of neuronal processes. The Fainzilber group has developed a new model for length-sensing in axons, based on motor-driven anterograde and retrograde transport along the cytoskeleton. The molecular motor based model overcomes the distance limitations of previously proposed diffusion based length-sensing mechanisms, and is supported by neurite length phenotypes in cultures from mutants impaired in the axonal retrograde transport system. However, although this new model can explain robust length signaling in the millimeter range, the velocity limits of molecular motors do not seem to be compatible with length sensing in much longer processes. Here, I suggest that a signaling mechanism based on retrograde phosphorylation waves modulated by an anterograde negative feedback signal may dramatically enhance robustness over a longer distance. I therefore propose to address this hypothesis by (I) identifying molecular interactors of the retrograde transport machinery in axons as candidate components of phosphorylation wave cascades, (II) testing the involvement of identified candidates in axonal length sensing and (III) directly imaging retrograde propagation of phosphorylation waves along axons. This research addresses a fundamental question in basic cell biology, and should greatly improve our understanding of how highly differentiated cells maintain system homeostasis.