Precise synaptic connectivity is a prerequisite for the function of neural circuits, yet individual neurons, taken out of their developmental context, readily form unspecific synapses. How does genetically encoded brain wiring deal with this apparent contradiction? Brain wiring is a developmental growth process that is not only characterized by precision, but also flexibility and robustness. As in any other growth process, cellular interactions are restricted in space and time. Correspondingly, molecular and cellular interactions are restricted to those that 'get to see' each other during development. This seminar will explore the question how neurons decide when and where to make synapses using the Drosophila visual system as a model. New findings reveal that pattern formation during growth and the kinetics of live neuronal interactions restrict synapse formation and partner choice for neurons that are not otherwise prevented from making incorrect synapses in this system. For example, cell biological mechanisms like autophagy as well as developmental temperature restrict inappropriate partner choice through a process of kinetic exclusion that critically contributes to wiring specificity. The seminar will explore these and other neuronal strategies when and where to make synapses during developmental growth that contribute to precise, flexible and robust outcomes in brain wiring.

Protein quality control is essential for maintenance of a healthy and functional proteome that can attend the multiplicity of cellular functions. Failure of the systems that contribute to protein homeostasis, the so called proteostasis networks, have been identified in the pathogenesis of multiple neurodegenerative disorders and demonstrated to contribute to disease onset and progression. We are interested in autophagy, one of the components of the proteostasis network, and in the interplay of wo selective types of autophagy, chaperone-mediated autophagy (CMA) and endosomal microautophagy (eMI), with neurodegeneration. We have recently found that pathogenic proteins involved in common neurodegenerative conditions such as tauopathies or Parkinson’s disease, can exert a toxic effect in both types of selective types of autophagy compromising their functioning. We have now used mouse models with compromised CMA that support increased propagation of proteins such as tau and alpha-synuclein and an exacerbation of disease phenotype with aging. Conversely, genetic or chemical upregulation of CMA in this context of proteotoxicity slow down disease progression by facilitating effective intracellular removal of pathogenic proteins. Our findings highlight CMA and eMI as potential novel therapeutic targets against neurodegeneration.