Small ubiquitin-related modifier 1

Small Ubiquitin-Related Modifier 1 (SUMO-1) is a protein that in humans is encoded by the SUMO1 gene. SUMO-1 is a member of the small ubiquitin-like modifier (SUMO) family. This family of proteins function by attaching to other proteins and altering their function or location. This process is known as SUMOylation.

Function

SUMO-1 is involved in various cellular processes, including nuclear transport, protein stability, stress response, and cell cycle regulation. It is a post-translational modifier that, unlike ubiquitin, does not target proteins for degradation but instead alters their function or subcellular location.

Structure

SUMO-1 is a small protein of 101 amino acids. It has a beta-grasp fold, which is a common structural motif found in ubiquitin-like proteins. The beta-grasp fold consists of a five-stranded beta-sheet wrapped around a single alpha-helix. SUMO-1 has a C-terminal diglycine motif, which is required for the conjugation to target proteins.

SUMOylation

SUMOylation is a reversible process that involves the covalent attachment of SUMO-1 to a target protein. This process is mediated by a series of enzymes known as E1, E2, and E3. The reverse process, known as deSUMOylation, is mediated by a family of enzymes known as SUMO-specific proteases (SENPs).

Clinical significance

Mutations in the SUMO1 gene have been associated with cleft lip and/or cleft palate. In addition, overexpression of SUMO-1 has been observed in several types of cancer, suggesting a role in tumorigenesis.

See also

• SUMO proteins
• Ubiquitin
• Post-translational modification