Advertisement

If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.

ENJOY UNLIMITED ACCES TO C&EN

Biological Chemistry

Sugar Helps Proteins Live Long And Prosper

Glycobiology: O-GlcNAc modification helps keep proteins out of the cellular garbage can

by Stu Borman
March 23, 2015 | A version of this story appeared in Volume 93, Issue 12

[+]Enlarge
Credit: Adapted from Nat. Chem. Biol.
O-GlcNAcylation of nascent proteins (upper left) prevents them from getting ubiquitinated (upper right). It thus promotes protein folding and longevity (lower left) and deters protein breakdown in the proteasome, the cellular trash compactor (lower right); Ub = ubiquitin.
A cartoon depicting ubiquitiation and its inhibition by O-GlcNAc.
Credit: Adapted from Nat. Chem. Biol.
O-GlcNAcylation of nascent proteins (upper left) prevents them from getting ubiquitinated (upper right). It thus promotes protein folding and longevity (lower left) and deters protein breakdown in the proteasome, the cellular trash compactor (lower right); Ub = ubiquitin.

O-GlcNAcylation, which is the modification of protein serine or threonine residues with the sugar N-acetylglucosamine (GlcNAc), plays a key role in cell physiology. But the mechanisms by which it acts are not completely understood. Yanping Zhu, David J. Vocadlo, and coworkers at Canada’s Simon Fraser University now report that O-GlcNAcylation occurs at higher levels cotranslationally—that is, while proteins are being synthesized on the ribosome—than posttranslationally (Nat. Chem. Biol. 2015, DOI: 10.1038/nchembio.1774). They also find that O-GlcNAcylation inhibits ubiquitination of nascent proteins, a modification that would otherwise mark them for disposal. Inhibiting ubiquitination thus stabilizes proteins and aids proteostasis, the maintenance of proper levels of functional proteins in cells. Vocadlo notes that his group hopes to learn more about the molecular mechanism by which O-GlcNAc decreases ubiquitination on the nascent chains.

Article:

This article has been sent to the following recipient:

0 /1 FREE ARTICLES LEFT THIS MONTH Remaining
Chemistry matters. Join us to get the news you need.