NEDD8
Encyclopedia
NEDD8 is a protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 that in humans is encoded by the NEDD8 gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

. (In Saccharomyces cerevisiae
Saccharomyces cerevisiae
Saccharomyces cerevisiae is a species of yeast. It is perhaps the most useful yeast, having been instrumental to baking and brewing since ancient times. It is believed that it was originally isolated from the skin of grapes...

this protein is known as Rub1.) This ubiquitin-like protein (ULP), which becomes covalently conjugated to a limited number of cellular proteins in a manner analogous to ubiquitination. Human NEDD8 shares 60% amino acid sequence identity to ubiquitin. The only known substrates of NEDD8 modification are the cullin subunits of SCF ubiquitin E3 ligases. The NEDDylation of cullins is critical for the recruitment of E2 to the ligase complex, thus facilitating ubiquitin conjugation. NEDD8 modification has therefore been implicated in cell cycle progression and cytoskeletal regulation.

As with ubiquitin and SUMO, NEDD8 is conjugated to cellular proteins after its C-terminal tail is processed. The NEDD8 activating E1 enzyme is a heterodimer composed of APPBP1 and UBA3 subunits. The APPBP1/UBA3 enzyme has homology to the N- and C-terminal halves of the ubiquitin E1 enzyme, respectively. The UBA3 subunit contains the catalytic center and activates NEDD8 in an ATP-dependent reaction by forming a high-energy thiolester intermediate. The activated NEDD8 is subsequently transferred to the UbcH12 E2 enzyme, and is then conjugated to specific substrates in the presence of the appropriate E3 ligases. There are several different proteases which can remove NEDD8 from protein conjugates. UCHL1, UCHL3 and USP21 proteases have dual specificity for NEDD8 and ubiquitin. Proteases specific for NEDD8 removal are the COP9 signalosome which removes NEDD8 from the CUL1 subunit of SCF ubiquitin ligases, and NEDP1 (or DEN1, SENP8).

Interactions

NEDD8 has been shown to interact
Protein-protein interaction
Protein–protein interactions occur when two or more proteins bind together, often to carry out their biological function. Many of the most important molecular processes in the cell such as DNA replication are carried out by large molecular machines that are built from a large number of protein...

 with UBE2M
UBE2M
NEDD8-conjugating enzyme Ubc12 is a protein that in humans is encoded by the UBE2M gene.-Interactions:UBE2M has been shown to interact with NEDD8, PRKAR1A and UBA3.-Further reading:...

, UBE1C
UBE1C
This enzyme contains an E2 binding domain, which resembles ubiquitin, and recruits the catalytic core of the E2 enzyme UBE2M in a similar manner to that in which ubiquitin interacts with ubiquitin binding domains.-Interactions:...

, NUB1
NUB1
NEDD8 ultimate buster 1 is a protein that in humans is encoded by the NUB1 gene.-Interactions:NUB1 has been shown to interact with NEDD8, UBD and AIPL1.-Further reading:...

, Aryl hydrocarbon receptor
Aryl hydrocarbon receptor
The Aryl hydrocarbon receptor is a member of the family of basic-helix-loop-helix transcription factors. AhR is a cytosolic transcription factor that is normally inactive, bound to several co-chaperones...

 and UCHL3
UCHL3
Ubiquitin carboxyl-terminal hydrolase isozyme L3 is an enzyme that in humans is encoded by the UCHL3 gene.-Interactions:UCHL3 has been shown to interact with NEDD8 and the tauopathy and synucleinopathy associated mutated ubiquitin molecule UBB+1....

.

Further reading

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