Ubiquitin is a highly conserved nuclear and cytoplasmic protein that has a major role in targeting cellular proteins for degradation by the 26S proteosome. It is also involved in the maintenance of chromatin structure, the regulation of gene expression, and the stress response. Ubiquitin is synthesized as a precursor protein consisting of either polyubiquitin chains or a single ubiquitin moiety fused to an unrelated protein. This gene encodes a fusion protein consisting of ubiquitin at the N terminus and ribosomal protein L40 at the C terminus, a C-terminal extension protein (CEP). Multiple processed pseudogenes derived from this gene are present in the genome. [provided by RefSeq, Jul 2008],
Function:
Function:Protein modifier which can be covalently attached to target lysines either as a monomer or as a lysine-linked polymer. Attachment to proteins as a Lys-48-linked polymer usually leads to their degradation by proteasome. Attachment to proteins as a monomer or as an alternatively linked polymer does not lead to proteasomal degradation and may be required for numerous functions, including maintenance of chromatin structure, regulation of gene expression, stress response, ribosome biogenesis and DNA repair.,miscellaneous:This ribosomal protein is synthesized as a C-terminal extension protein (CEP) of ubiquitin.,miscellaneous:Ubiquitin is synthesized as a polyubiquitin precursor with exact head to tail repeats, the number of repeats differ between species and strains. In some species there is a final amino-acid after the last repeat, here in human a Val. Some ubiquitin genes contain a single copy of ubiquitin fused to a ribosomal protein (either L40 or S27a).,PTM:Several types of polymeric chains can be formed, depending on the lysine used for the assembly.,similarity:Belongs to the ribosomal protein L40e family.,similarity:Belongs to the ribosomal protein S27Ae family.,similarity:Belongs to the ubiquitin family.,