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Title: Structural analysis of Notch-regulating Rumi reveals basis for pathogenic mutations

We present Rumi O-glucosylates the EGF repeats of a growing list of proteins essential in metazoan development, including Notch. Rumi is essential for Notch signaling, and Rumi dysregulation is linked to several human diseases. Despite Rumi's critical roles, it is unknown how Rumi glucosylates a serine of many but not all EGF repeats. Here we report crystal structures of Drosophila Rumi as binary and ternary complexes with a folded EGF repeat and/or donor substrates. These structures provide insights into the catalytic mechanism and show that Rumi recognizes structural signatures of the EGF motif, the U-shaped consensus sequence, C-X-S-X-(P/A)-C and a conserved hydrophobic region. We found that five Rumi mutations identified in cancers and Dowling–Degos disease are clustered around the enzyme active site and adversely affect its activity. In conclusion, our study suggests that loss of Rumi activity may underlie these diseases, and the mechanistic insights may facilitate the development of modulators of Notch signaling.
 [1] ;  [2] ;  [2] ;  [1] ;  [3] ;  [2] ;  [1]
  1. Brookhaven National Lab. (BNL), Upton, NY (United States). Biology Department
  2. Univ. of Georgia, Athens, GA (United States). Complex Carbohydrate Research Center
  3. Stony Brook Univ., NY (United States). Department of Biochemistry and Cell Biology
Publication Date:
Report Number(s):
Journal ID: ISSN 1552-4450
Grant/Contract Number:
SC00112704; AC02-98CH10886; AC02-06CH11357
Accepted Manuscript
Journal Name:
Nature Chemical Biology
Additional Journal Information:
Journal Volume: 12; Journal Issue: 9; Journal ID: ISSN 1552-4450
Nature Publishing Group
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Institute of Health
Country of Publication:
United States
59 BASIC BIOLOGICAL SCIENCES; 60 APPLIED LIFE SCIENCES; Cancer; Enzyme mechanisms; Glycobiology; X-ray crystallography
OSTI Identifier: