Neuronal dysfunction in Alzheimer's (AD) and related neurodegenerative diseases correlates with the aggregation of the microtubule associated protein Tau. Tau seems to induce a number of cellular changes that are mediated by disease-conditional interactions of Tau with other proteins, organelles, and RNA. Tau has a high affinity to RNA, and Tau:RNA interactions were shown to influence its canonical function in microtubule binding and promote its aggregation. The (patho)physiological role of Tau:RNA interactions remains understudied though. Here, we aim to decipher the interactions of Tau with non-coding RNAs (ncRNAs) and determine their impact processes that are altered in response to Tau. We will decipher neuronal Tau:RNA interactions in physiological versus pro-pathological stress conditions, study Tau:ncRNA interactions on the molecular level and determine the impact on key cellular processes, develop strategies to block abnormal Tau:ncRNA interactions, and explore the relevance of these findings for Tau biology in human neurons. The findings of this work will for the first time elucidate the role of ncRNAs in Tau (patho)biology and therefore have a large impact far beyond this proposal.