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Altelaar, M.

Publications and source records attributed to Altelaar, M..

2 recordsLinked to original sources

Fibril formation rewires interactome of the Alzheimer protein Tau by π-stacking

Aggregation of the Tau protein defines progression of neurodegenerative diseases, including Alzheimers Disease. Tau assembles into oligomers and fibrils. The molecular basis of their toxicity is poorly understood. Here we show that {pi}-stacking by Arginine side chains rewires the interactome of Tau upon aggregation. Oligomeric nano-aggregates scavenge the COPI complex, fibrils attract proteins involved in microtubule binding, RNA binding and phosphorylation. The aberrant interactors have disordered regions with unusual sequence features. Arginines are crucial to initiate such aberrant interactions. Remarkably, substitution of Arginines by Lysines abolishes scavenging, which indicates a key role for the pi-stacking of the Arginine side chain. The molecular chaperone Hsp90 tames such re-arrangements, which suggests that the natural protein quality control system can suppress aberrant interactions. Together, our data present a molecular mode of action for derailment of protein-protein interaction in neurodegeneration.\n\nHIGHLIGHTSO_LITau fibrils act as fishing net for proteins.\nC_LIO_LITau fibrils attract specific protein families associated with Alzheimer.\nC_LIO_LI{pi}-stacking by Arginines key for aberrant binding to Tau fibrils\nC_LIO_LIThe Hsp90 chaperone stalls fibril growth and alters interactome\nC_LI

biochemistry

Evolutionarily-conserved chromatin crosstalk generates a DOT1L-dose dependency in thymic lymphoma caused by loss of HDAC1

DOT1L methylates histone H3K79 and is aberrantly regulated in MLL-rearranged leukemia. Inhibitors have been developed to target DOT1L activity in leukemia but the cellular mechanisms that regulate DOT1L are still poorly understood. Here we identify the budding yeast histone deacetylase Rpd3 as a negative regulator of Dot1. At its target genes, the transcriptional repressor Rpd3 restricts H3K79 methylation, explaining the absence of H3K79me3 at a subset of genes in the yeast genome. Similar to the crosstalk in yeast, inactivation of the murine Rpd3 homolog HDAC1 in thymocytes led to an increase in H3K79 methylation. Thymic lymphomas that arise upon genetic deletion of Hdac1 retained the increased H3K79 methylation and were sensitive to reduced DOT1L dosage. Furthermore, cell lines derived from Hdac1{Delta}/{Delta} thymic lymphomas were sensitive to DOT1L inhibitor, which induced apoptosis. In summary, we identified an evolutionarily-conserved crosstalk between HDAC1 and DOT1L with impact in murine thymic lymphoma development.

cell biology