Eukaryotic cells contains thousands of different proteins, many of which are required for only brief periods during the cellular cycle. These short-lived proteins, along with any misfolded or damaged intracellular proteins, are destroyed by a large proteolytic complex named the 26S proteasome.... read more
CRISPR-mediated prokaryotic immunity
In E. coli, CRISPR transcripts are processed into short RNAs that are incorporated into a large ribonucleoprotein surveillance complex called Cascade. This complex specifically targets and binds foreign nucleic acids in a sequence-specific manner, followed by degradation of the targeted substrate. We used cryo-electron microscopy to determine the structure of Cascade before and after binding to a target substrate... read more
Exosome and RNA Processing
The eukaryotic exosome is a conserved complex important for 3' end trimming and degradation of RNA. In yeast, the Rrp44 protein constitutively associates with the nine-subunit core exosome and provides the sole sources of processive 3'-to-5' exoribonuclease activity. We have obtained EM reconstructions of the core and Rrp44-bound exosome complexes... read more
Congratulations to Randy Schekman on his Nobel Prize!
Celebrating on October 7th: John Kuriyan, Susan Marqusee, RANDY SCHEKMAN, Eva Nogales and Olga Boudker (visiting from Cornell)