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Although energy-dependent protein destruction by the proteasome has been known for over 30 years, how this intricate molecular machine uses ATP to power protein degradation has remained very poorly understood. In a recently published paper, Ding et al. present a snapshot of the proteasome mid-catalysis, yielding new and unexpected insights into the catalytic mechanism of this ATP-powered multisubunit machine.
An ability to convert between pancreatic islet cell types may provide a new approach to replace insulin-secreting β cells destroyed by autoimmune attack in Type 1 diabetes. Two papers, which have recently appeared in Cell, describe how this might be achieved.
Mitophagy, the selective autophagic elimination of mitochondria, is a conserved cellular process critical for maintaining normal cellular physiology, and defects in this process are associated with certain pathophysiologies. In a recently published paper, Wei et al. describe their discovery of a hitherto unexplored mechanism of marking mitochondria for degradation.
In bacteria and archaea, CRISPR-Cas adaptive immune systems utilize RNA-guided endonucleases to defend against invasion by foreign nucleic acids of bacteriophage, virus and plasmid origin. In a recent paper published in Nature, Burstein et al. identified the first Cas9 protein in uncultivated archaea and two novel CRISPR-CasX and CRISPR-CasY systems in uncultivated bacteria by capitalizing on analysis of terabase-scale metagenomic datasets from natural uncultivated organisms.