Uridylylation

Uridylylation is a post-translational modification where a uridylyl group, derived from UTP, is covalently attached to a target protein. This process is catalyzed by specific uridylyltransferases. The addition of a uridylyl moiety can significantly alter the protein's function, stability, or localization. It is a reversible modification, with de-uridylylases responsible for removing the uridylyl group.

This modification plays a role in various cellular processes, including signal transduction and metabolic regulation. For instance, uridylylation is a key regulatory mechanism for enzymes involved in nitrogen assimilation, such as glutamine synthetase. In bacteria, the uridylylation state of glutamine synthetase determines its activity, with uridylylation typically leading to its inactivation. This allows cells to fine-tune metabolic pathways in response to environmental conditions.

Research into uridylylation has revealed its importance in maintaining cellular homeostasis. While not as extensively studied as other post-translational modifications like phosphorylation or ubiquitination, uridylylation is gaining recognition as a crucial regulatory mechanism. The enzymes involved and the specific substrates continue to be areas of active investigation, promising further insights into cellular signaling and metabolic control.