Alzheimer's disease is characterized by the accumulation of neurotoxic β-amyloid peptide (A-beta). ADAM10, a protein that resides in the neural synapses, has previously been shown to prevent the formation of A-beta. In a study published on the Journal of Clinical Investigation, Monica Di Luca and colleagues at the University of Milan report that ADAM10 is removed from synapses through association with the protein AP2.

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Two Italian researchers from La Sapienza University, Claudio Conti and Marco Leonetti, in collaboration with a team of scientists from Instituto de Ciencia de Materiales de Madrid Cefe Lopez, demonstrated that a new kind of transistor can get power from disordered system, such as liquids, gas or metals even if made of a much simpler structure compared to the optic ones. In this way it could be possible for a light beam, for example, to pass through a wall keeping the control of the signal.

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A new research about the conformational switch in HP1 that releases auto-inhibition to drive heterochromatin assembly, lead by the Italian Daniele Canzio, has just been published on Nature magazine. According to the research, a hallmark of histone H3 lysine 9 (H3K9)-methylated heterochromatin, conserved from the fission yeast Schizosaccharomyces pombe to humans, is able to spread to adjacent genomic regions. Central to heterochromatin spread is heterochromatin protein 1 (HP1), which recognizes H3K9-methylated chromatin, oligomerizes and forms a versatile platform that participates in diverse nuclear functions, ranging from gene silencing to chromosome segregation. How HP1 proteins assemble on methylated nucleosomal templates and how the HP1–nucleosome complex achieves functional versatility remain poorly understood. Here we show that binding of the key S. pombe HP1 protein, Swi6, to methylated nucleosomes drives a switch from an auto-inhibited state to a spreading-competent state. In the auto-inhibited state, a histone-mimic sequence in one Swi6 monomer blocks methyl-mark recognition by the chromodomain of another monomer. Auto-inhibition is relieved by recognition of two template features, the H3K9 methyl mark and nucleosomal DNA. Cryo-electron-microscopy-based reconstruction of the Swi6–nucleosome complex provides the overall architecture of the spreading-competent state in which two unbound chromodomain sticky ends appear exposed. Disruption of the switch between the auto-inhibited and spreading-competent states disrupts heterochromatin assembly and gene silencing in vivo. These findings are reminiscent of other conditionally activated polymerization processes, such as actin nucleation, and open up a new class of regulatory mechanisms that operate on chromatin in vivo.

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