Molecular features of human ubiquitin-like SUMO genes and their encoded proteins

Gene. 2002 Aug 21;296(1-2):65-73. doi: 10.1016/s0378-1119(02)00843-0.

Abstract

The SUMO (small ubiquitin-like modifier) protein and ubiquitin have similar 3-D structure. Sumolyzation and ubiquitination exhibit similar biological processes for post-translational modification. However, unlike ubiquitination, which targets proteins for degradation, sumolyzation participates in a number of cellular processes such as nuclear transport, transcriptional regulation, apoptosis and protein stability. The human genome contains three SUMO-1/2/3 functional genes, as well as eight SUMO-1 pseudogenes and 23 SUMO-2 pseudogenes, but no SUMO-3 pseudogenes. The protein-coding sequence of the SUMO-1 gene is interrupted by four introns, while those of SUMO-2 and SUMO-3 genes are interrupted by three introns. Human SUMO-1 protein exhibits 44% sequence identity with SUMO-2 and SUMO-3 proteins, while SUMO-2 and SUMO-3 proteins share 86% sequence identity. Phylogenetic analyses indicate that the SUMO-3 gene was derived from the SUMO-2 gene. SUMO-1 mRNA appears to be most abundant in human epithelial HeLa, kidney 293 and neuronal NT2 cells, while the SUMO-3 mRNA seems to be much less abundant than SUMO-2 mRNA, especially in HeLa and 293 cells. Many cellular proteins of high molecular weights were covalently modified by SUMO-1/2/3 proteins. However, some free form of SUMO-2/3 proteins was also detected. Most SUMO-1/2/3 proteins were shown to be localized on nuclear membrane, nuclear bodies and cytoplasm, respectively.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Blotting, Western
  • Cell Line
  • Cell Nucleus / metabolism
  • Cytosol / metabolism
  • Evolution, Molecular
  • Exons
  • Gene Expression
  • Genes / genetics
  • Genome, Human
  • HeLa Cells
  • Humans
  • Introns
  • Microscopy, Fluorescence
  • Molecular Sequence Data
  • Multigene Family / genetics*
  • Nuclear Envelope / metabolism
  • Phylogeny
  • Proteins / metabolism
  • Pseudogenes / genetics
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • SUMO-1 Protein / genetics
  • SUMO-1 Protein / metabolism
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Sequence Homology, Nucleic Acid
  • Small Ubiquitin-Related Modifier Proteins / genetics*
  • Small Ubiquitin-Related Modifier Proteins / metabolism
  • Tumor Cells, Cultured
  • Ubiquitins / genetics
  • Ubiquitins / metabolism

Substances

  • Proteins
  • RNA, Messenger
  • SUMO-1 Protein
  • SUMO2 protein, human
  • SUMO3 protein, human
  • Small Ubiquitin-Related Modifier Proteins
  • Ubiquitins