UBE4B, Kr. 1p36.22 ( neuroblastoma tuumorisuppressiogeeni)
Ubikitinaatio käsittää ainakin kolmen luokan entsyymeitä:
Ubikitiinia aktivoivat entyymit E1
Ubikitiinia konjugoivat entsyymit E2
Ubikitiini-proteiini-ligaasit E3.
Sitten vielä lisätekijät konjugoiva faktori E4, joka vastaa multiubikitinaatiossa ketjun kokoamisesta.
- Also known as
- E4; UFD2; HDNB1; UBOX3; UFD2A
- Summary
- The modification of proteins with ubiquitin is an important cellular mechanism for targeting abnormal or short-lived proteins for degradation. Ubiquitination involves at least three classes of enzymes: ubiquitin-activating enzymes, or E1s, ubiquitin-conjugating enzymes, or E2s, and ubiquitin-protein ligases, or E3s. This gene encodes an additional conjugation factor, E4, which is involved in multiubiquitin chain assembly. This gene is also the strongest candidate in the neuroblastoma tumor suppressor genes. Alternatively spliced transcript variants encoding distinct isoforms have been found for this gene. [provided by RefSeq, Jul 2008]
- Expression
- Ubiquitous expression in thyroid (RPKM 12.1), skin (RPKM 10.9) and 25 other tissues See more
- UB4A, kr. 11q23.3 (Ilmenee kortikaalisessa neuronissa)
- https://www.ncbi.nlm.nih.gov/gene/9354
- known as E4; UFD2; UBOX2
- This gene encodes a member of the U-box ubiquitin ligase family. The encoded protein is involved in multiubiquitin chain assembly and plays a critical role in chromosome condensation and separation through the polyubiquitination of securin. Autoantibodies against the encoded protein may be markers for scleroderma and Crohn's disease. A pseudogene of this gene is located on the long arm of chromosome 3. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene. [provided by RefSeq, Feb 2011]
- Expression
- Ubiquitous expression in brain (RPKM 15.5), appendix (RPKM 14.1) and 25 other tissues See more
- The Ubiquitination Factor E4A gene (UBE4A) encodes for a U-box-type ubiquitin ligase, originally described as an E4 ubiquitination factor. UBE4A is a mammalian homolog of Saccharomyces cerevisiae Ufd2. The UBE4A gene has been mapped on the human chromosome region 11q23.3, a critical region involved in some specific cancers such as neuroblastoma. Northern blots analysis on foetal and adult human tissues revealed a single band of approximately 7.5 kb transcript most abundant in the heart, skeletal muscle and kidney. We generated a polyclonal antibody to UBE4A and performed immunoblot and immunohistochemical analysis. The UBE4A protein appeared as a single band of approximately 125 kDa. UBE4A was present in the skeletal muscle, kidney and liver; a faint band was visible in peripheral blood leukocytes and spleen. We did not reveal expression of UBE4A in whole brain, colon, lung and heart. At the cellular level, UBE4A results predominantly expressed in the nucleus and the cytoplasm of cortical neurons and liver and in the nucleus of tubular kidney cells. In the liver, the nucleus of similar cells appeared to be unstained or stained at different levels suggesting that UBE4A may have a cell cycle dependent expression or a role of in cell cycle control. In conclusion, our results show that UBE4A is expressed in different tissues in a pattern that seems to be dependent from cell type and cell cycle and that UBE4A might have a specific role in different biochemical processes other than ubiquitination, including growth or differentiation.
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