ubiquitin

Ubiquitin

Ubiquitin is a small (8.5 kDa) regulatory protein that has been found in almost all tissues (ubiquitously) of eukaryotic organisms. It was discovered in 1975 by Gideon Goldstein and further characterized throughout the 1970s and 1980s.

There are four genes in the human genome that produce ubiquitin: UBB, UBC, UBA52, and RPS27A.

The addition of ubiquitin to a substrate protein is called ubiquitination or ubiquitylation. Ubiquitination can affect proteins in many ways: it can signal their degradation via the proteasome, alter their cellular location, affect their activity, and promote or prevent protein interactions.

Ubiquitination is carried out in three main steps: activation, conjugation, and ligation, performed by ubiquitin-activating enzymes (E1s), ubiquitin-conjugating enzymes (E2s), and ubiquitin ligases (E3s), respectively. The result of this sequential cascade binds ubiquitin to lysine residues on the protein substrate via an isopeptide bond, cysteine residues through a thioester bond, serine and threonine residues through an ester bond, or the amino group of the protein's N-terminus via a peptide bond.


Blood ubiquitin C-terminal hydrolase (UCH-L1) and GFAP are increased early after stroke and distinct biomarker-specific release profiles are associated with stroke characteristics and type. Ren et al confirmed the potential of GFAP as a tool for early rule-in of ICH, while UCH-L1 was not clinically useful 1).


1)
Ren C, Kobeissy F, Alawieh A, Li N, Li N, Zibara K, Zoltewicz S, Guingab-Cagmat J, Larner SF, Ding Y, Hayes RL, Ji X, Mondello S. Assessment of Serum UCH-L1 and GFAP in Acute Stroke Patients. Sci Rep. 2016 Apr 14;6:24588. doi: 10.1038/srep24588. PubMed PMID: 27074724; PubMed Central PMCID: PMC4830936.
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  • Last modified: 2022/05/10 13:35
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