USP6 | |||||||||||||||||||||||||||||||||||||||||||||||||||
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Identifiers | |||||||||||||||||||||||||||||||||||||||||||||||||||
Aliases | USP6 , HRP1, TRE17, TRE2, TRESMCR, Tre-2, USP6-short, ubiquitin specific peptidase 6 | ||||||||||||||||||||||||||||||||||||||||||||||||||
External IDs | OMIM: 604334 HomoloGene: 136783 GeneCards: USP6 | ||||||||||||||||||||||||||||||||||||||||||||||||||
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Ubiquitin carboxyl-terminal hydrolase 6 (USB6), also termed TRE17 and Tre-2, is a deubiquitinating enzyme [3] that in humans is encoded by the hominid (i.e. found only in primates) USP6 gene [4] [5] [6] located at band 13.2 on the short (i.e. "p") arm of chromosome 17 (notated as 17p13.2). [7] Deubiquitinating enzymes (DUBs) are enzymes that act within cells to remove ubiquitins from various functionally important proteins. Ubiquitin enzymes add ubiquitin to these proteins and thereby regulate their cellular location, alter their activity, and/or promote their degradation. By deubiquitinating these proteins, DUBs counter the effects of the ubiquinating enzymes and contribute to regulating the actions of the targeted proteins. [8] In normal adult tissues, USP6 is highly expressed in testicle tissue, modestly expressed in ovarian tissue, and absent or minimally expressed in other tissues. [9] It is also highly expressed in fetal brain tissue. The specific functions of USP6 are poorly defined primarily because its presence is restricted to primates: there are no available animal models to determine the effects of its deletion, although some studies suggest that UPSP6 contributes to normal brain development. [7] In all events, USP6 has gained wide interest because of its abnormally increased expression by the neoplastic cells in various tumors derived from mesenchymal tissue.
The USP6 gene associated with tumors is part of a fusion gene. Fusion genes are abnormal and potentially tumor-inducing genes formed by mergers between parts of two different genes as a result of large scale gene mutations such as chromosomal translocations, interstitial deletions, or inversions. For example, the USP6-COL1A1 fusion gene is formed by a translocation between part of the USP6 gene located at band 13.2 on the p arm of chromosome 17 and the COL1A1 gene located at band 21.33 on the q arm of this same chromosome. [10] The USP6 gene has been documented to fuse with any one of scores of other genes and in doing so (as tested in many cases) create a fusion gene that is overproduced and contains high levels of deubiquitinating activity. [11] Studies suggest that USP6-containing fusion genes cause or at least contribute to tumor development by inappropriately activating multiple cell signaling pathways including the Wnt signaling pathway, one of the JAK-STAT signaling pathways (i.e. the Jak1-STAT3 pathway), the c-Jun signaling pathway, [12] and the NF-κB signaling pathway. [13] All of these pathways, when inappropriately activated, have been implicated in promoting the development of tumors and cancers. [12] The World Health Organization, 2021, classification of Tumors of Soft Tissue suggests that USP6-containing fusion protein-associated tumors are typically benign and usually self-limited in their growth. [12] Furthermore, high levels of USP6 activity may act to suppress rather than promote tumor development in Ewing sarcoma, a tumor which has USP-containing fusion genes in ~1/3 of cases. [3]
Tumor types that are associated with USP6-containing fusion genes and appear to promote their development and/or growth include:
Deubiquitinating enzymes (DUBs), also known as deubiquitinating peptidases, deubiquitinating isopeptidases, deubiquitinases, ubiquitin proteases, ubiquitin hydrolases, or ubiquitin isopeptidases, are a large group of proteases that cleave ubiquitin from proteins. Ubiquitin is attached to proteins in order to regulate the degradation of proteins via the proteasome and lysosome; coordinate the cellular localisation of proteins; activate and inactivate proteins; and modulate protein-protein interactions. DUBs can reverse these effects by cleaving the peptide or isopeptide bond between ubiquitin and its substrate protein. In humans there are nearly 100 DUB genes, which can be classified into two main classes: cysteine proteases and metalloproteases. The cysteine proteases comprise ubiquitin-specific proteases (USPs), ubiquitin C-terminal hydrolases (UCHs), Machado-Josephin domain proteases (MJDs) and ovarian tumour proteases (OTU). The metalloprotease group contains only the Jab1/Mov34/Mpr1 Pad1 N-terminal+ (MPN+) (JAMM) domain proteases.
Nodular fasciitis (NF) is a benign, soft tissue tumor composed of myofibroblasts that typically occurs in subcutaneous tissue, fascia, and/or muscles. The literature sometimes titles rare NF variants according to their tissue locations. The most frequently used and important of these are cranial fasciitis and intravascular fasciitis. In 2020, the World Health Organization classified nodular fasciitis as in the category of benign fibroblastic/myofibroblastic tumors. NF is the most common of the benign fibroblastic proliferative tumors of soft tissue.
Aneurysmal bone cyst (ABC) is a non-cancerous bone tumor composed of multiple varying sizes of spaces in a bone which are filled with blood. The term is a misnomer, as the lesion is neither an aneurysm nor a cyst. It generally presents with pain and swelling in the affected bone. Pressure on neighbouring tissues may cause compression effects such as neurological symptoms.
Growth differentiation factor-3 (GDF3), also known as Vg-related gene 2 (Vgr-2) is protein that in humans is encoded by the GDF3 gene. GDF3 belongs to the transforming growth factor beta (TGF-β) superfamily. It has high similarity to other TGF-β superfamily members including Vg1 and GDF1.
SUMO-conjugating enzyme UBC9 is an enzyme that in humans is encoded by the UBE2I gene. It is also sometimes referred to as "ubiquitin conjugating enzyme E2I" or "ubiquitin carrier protein 9", even though these names do not accurately describe its function.
CDC34 is a gene that in humans encodes the protein Ubiquitin-conjugating enzyme E2 R1. This protein is a member of the ubiquitin-conjugating enzyme family, which catalyzes the covalent attachment of ubiquitin to other proteins.
E3 ubiquitin-protein ligase Topors is an enzyme that in humans is encoded by the TOPORS gene.
Large tumor suppressor kinase 1 (LATS1) is an enzyme that in humans is encoded by the LATS1 gene.
Platelet-derived growth factor C, also known as PDGF-C, is a 345-amino acid protein that in humans is encoded by the PDGFC gene. Platelet-derived growth factors are important in connective tissue growth, survival and function, and consist of disulphide-linked dimers involving two polypeptide chains, PDGF-A and PDGF-B. PDGF-C is a member of the PDGF/VEGF family of growth factors with a unique two-domain structure and expression pattern. PDGF-C was not previously identified with PDGF-A and PDGF-B, possibly because it may be that it is synthesized and secreted as a latent growth factor, requiring proteolytic removal of the N-terminal CUB domain for receptor binding and activation.
Ubiquitin-conjugating enzyme E2 variant 1 is a protein that in humans is encoded by the UBE2V1 gene.
Ubiquitin-conjugating enzyme E2 B is a protein that in humans is encoded by the UBE2B gene.
E3 ubiquitin-protein ligase FANCL is an enzyme that in humans is encoded by the FANCL gene.
Ubiquitin carboxyl-terminal hydrolase 16 is an enzyme that in humans is encoded by the USP16 gene.
Ubiquitin specific protease 4 (USP4) is an enzyme that cleaves ubiquitin from a number of protein substrates. Prior to the standardization of nomenclature USP4 was known as UNP, and was one of the first deubiquitinating enzymes to be identified in mammals. In the mouse and human the USP4 protein is encoded by a gene containing 22 exons.
Ubiquitin carboxyl-terminal hydrolase isozyme L3 is an enzyme that in humans is encoded by the UCHL3 gene.
NUAK family SNF1-like kinase 1 also known as AMPK-related protein kinase 5 (ARK5) is an enzyme that in humans is encoded by the NUAK1 gene.
Ubiquitin carboxyl-terminal hydrolase 2 is an enzyme that in humans is encoded by the USP2 gene.
Ubiquitin carboxyl-terminal hydrolase 13 is an enzyme that in humans is encoded by the USP13 gene.
Proliferative fasciitis and proliferative myositis (PF/PM) are rare benign soft tissue lesions that increase in size over several weeks and often regress over the ensuing 1–3 months. The lesions in PF/PM are typically obvious tumors or swellings. Historically, many studies had grouped the two descriptive forms of PF/PM as similar disorders with the exception that proliferative fasciitis occurs in subcutaneous tissues while proliferative myositis occurs in muscle tissues. In 2020, the World Health Organization agreed with this view and defined these lesions as virtually identical disorders termed proliferative fasciitis/proliferative myositis or proliferative fasciitis and proliferative myositis. The Organization also classified them as one of the various forms of the fibroblastic and myofibroblastic tumors.
The PPP6R3 gene is located at band 13.2 on the long arm of chromosome 11 and is expressed in all tissues tested in humans. It encodes protein phosphatase 6 regulatory subunit 3 (PP6RS3). Also termed serine/threonine-protein phosphatase 6 regulatory subunit 3, PP6RS3 is the function-regulating subunit of protein phosphatase 6 (PPP6C). PPP6C is a component of a signaling pathway that regulates various cell functions including cell division, the repair of damaged DNA, inflammatory responses, messenger mRNA splicing, and the stability of chromosomes.