UCHL1 | |||||||||||||||||||||||||||||||||||||||||||||||||||
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Aliases | UCHL1 , HEL-117, NDGOA, PARK5, PGP 9.5, PGP9.5, PGP95, Uch-L1, HEL-S-53, ubiquitin C-terminal hydrolase L1, SPG79, UCHL-1 | ||||||||||||||||||||||||||||||||||||||||||||||||||
External IDs | OMIM: 191342 MGI: 103149 HomoloGene: 37894 GeneCards: UCHL1 | ||||||||||||||||||||||||||||||||||||||||||||||||||
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Ubiquitin carboxy-terminal hydrolase L1 (EC 3.1.2.15, ubiquitin C-terminal hydrolase, UCH-L1) is a deubiquitinating enzyme.
Ubiquitin Carboxy-terminal Hydrolase L1 (UCH-L1) | |
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Anatomical terms of microanatomy |
UCH-L1 is a member of a gene family whose products hydrolyze small C-terminal adducts of ubiquitin to generate the ubiquitin monomer. Expression of UCH-L1 is highly specific to neurons and to cells of the diffuse neuroendocrine system and their tumors. It is abundantly present in all neurons (accounts for 1-2% of total brain protein), expressed specifically in neurons and testis/ovary. [5] [6]
The catalytic triad of UCH-L1 contains a cysteine at position 90, an aspartate at position 176, and a histidine at position 161 that are responsible for its hydrolase activity. [7]
A point mutation (I93M) in the gene encoding this protein is implicated as the cause of Parkinson's disease in one German family, although this finding is controversial, as no other Parkinson's disease patients with this mutation have been found. [8] [9]
Furthermore, a polymorphism (S18Y) in this gene has been found to be associated with a reduced risk for Parkinson's disease. [10] This polymorphism has specifically been shown to have antioxidant activity. [11]
Another potentially protective function of UCH-L1 is its reported ability to stabilize monoubiquitin, an important component of the ubiquitin proteasome system. It is thought that by stabilizing the monomers of ubiquitin and thereby preventing their degradation, UCH-L1 increases the available pool of ubiquitin to be tagged onto proteins destined to be degraded by the proteasome. [12]
The gene is also associated with Alzheimer's disease, and required for normal synaptic and cognitive function. [13] Loss of Uchl1 increases the susceptibility of pancreatic beta-cells to programmed cell death, indicating that this protein plays a protective role in neuroendocrine cells and illustrating a link between diabetes and neurodegenerative diseases. [14]
Patients with early-onset neurodegeneration in which the causative mutation was in the UCHL1 gene (specifically, the ubiquitin binding domain, E7A) display blindness, cerebellar ataxia, nystagmus, dorsal column dysfunction, and upper motor neuron dysfunction. [15]
Although UCH-L1 protein expression is specific to neurons and testis/ovary tissue, it has been found to be expressed in certain lung-tumor cell lines. [16] This abnormal expression of UCH-L1 is implicated in cancer and has led to the designation of UCH-L1 as an oncogene. [17] Furthermore there is evidence that UCH-L1 might play a role in the pathogenesis of membranous glomerulonephritis as UCH-L1 de novo expression in podocytes was seen in PHN, the rat model of human mGN. [18] This UCH-L1 expression is thought to induce at least in part podocyte hypertrophy. [19]
Human UCH-L1 and the closely related protein UCHL3 have one of the most complicated knot structure yet discovered for a protein, with five knot crossings. It is speculated that a knot structure may increase a protein's resistance to degradation in the proteasome. [20] [21]
The conformation of the UCH-L1 protein may also be an important indication of neuroprotection or pathology. For example, the UCH-L1 dimer has been shown to exhibit the potentially pathogenic ligase activity and may lead to the aforementioned increase in aggregation of α-synuclein. [22] The S18Y polymorphism of UCH-L1 has been shown to be less-prone to dimerization. [12]
Ubiquitin carboxy-terminal hydrolase L1 has been shown to interact with COP9 constitutive photomorphogenic homolog subunit 5. [23]
UCH-L1 has also been shown to interact with α-synuclein, another protein implicated in the pathology of Parkinson disease. This activity is reported to be the result of its ubiquityl ligase activity which may be associated with the I93M pathogenic mutation in the gene. [22]
Most recently, UCH-L1 has been demonstrated to interact with the E3 ligase, parkin. Parkin has been demonstrated to bind and ubiquitinylate UCH-L1 to promote lysosomal degradation of UCH-L1. [24]
Lewy bodies are the inclusion bodies – abnormal aggregations of protein – that develop inside nerve cells affected by Parkinson's disease (PD), the Lewy body dementias, and some other disorders. They are also seen in cases of multiple system atrophy, particularly the parkinsonian variant (MSA-P).
Alpha-synuclein(aSyn) is a protein that, in humans, is encoded by the SNCA gene. Alpha-synuclein is a neuronal protein that regulates synaptic vesicle trafficking and subsequent neurotransmitter release.
Parkin is a 465-amino acid residue E3 ubiquitin ligase, a protein that in humans and mice is encoded by the PARK2 gene. Parkin plays a critical role in ubiquitination – the process whereby molecules are covalently labelled with ubiquitin (Ub) and directed towards degradation in proteasomes or lysosomes. Ubiquitination involves the sequential action of three enzymes. First, an E1 ubiquitin-activating enzyme binds to inactive Ub in eukaryotic cells via a thioester bond and mobilises it in an ATP-dependent process. Ub is then transferred to an E2 ubiquitin-conjugating enzyme before being conjugated to the target protein via an E3 ubiquitin ligase. There exists a multitude of E3 ligases, which differ in structure and substrate specificity to allow selective targeting of proteins to intracellular degradation.
Deubiquitinating enzymes (DUBs), also known as deubiquitinating peptidases, deubiquitinating isopeptidases, deubiquitinases, ubiquitin proteases, ubiquitin hydrolases, 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.
UBB+1 is shorthand for Ubiquitin-B+1, a frameshifted mutant arising from the Ubiquitin B gene. UBB+1 is thought to arise from molecular misreading, a poorly understood process. Molecular misreading introduces dinucleotide deletions into mRNA transcripts. These deletions are not present in genomic DNA. UBB+1 has been observed in the hallmarks of Alzheimer's disease, as well as other tauopathies and in polyglutamine diseases but not in synucleinopathies. Since its discovery it has been shown in vitro and in vivo that UBB+1 inhibits the proteasome and gives rise to downstream effects. In non-neuronal cells UBB+1 also accumulates suggesting a functional role in non-neuronal diseases. UBB+1 can be truncated by yeast's ubiquitin hydrolase 1 (YUH1) and ubiquitin C-terminal hydrolase L3 UCHL3 even though the glycine at position 76 has been substituted for a tyrosine.
Cyclopentenone prostaglandins are a subset of prostaglandins (PGs) or prostanoids that has 15-deoxy-Δ12,14-prostaglandin J2 (15-d-Δ12,14-PGJ2), Δ12-PGJ2, and PGJ2 as its most prominent members but also including PGA2, PGA1, and, while not classified as such, other PGs. 15-d-Δ12,14-PGJ2, Δ12-PGJ2, and PGJ2 share a common mono-unsaturated cyclopentenone structure as well as a set of similar biological activities including the ability to suppress inflammation responses and the growth as well as survival of cells, particularly those of cancerous or neurological origin. Consequently, these three cyclopentenone-PGs and the two epoxyisoprostanes are suggested to be models for the development of novel anti-inflammatory and anti-cancer drugs. The cyclopenentone prostaglandins are structurally and functionally related to a subset of isoprostanes viz., two cyclopentenone isoprostanes, 5,6-epoxyisoprostane E2 and 5,6-epoxisoprostane A2.
Beta-synuclein is a protein that in humans is encoded by the SNCB gene.
Gamma-synuclein is a protein that in humans is encoded by the SNCG gene.
Leucine-rich repeat kinase 2 (LRRK2), also known as dardarin and PARK8, is a large, multifunctional kinase enzyme that in humans is encoded by the LRRK2 gene. LRRK2 is a member of the leucine-rich repeat kinase family. Variants of this gene are associated with an increased risk of Parkinson's disease and Crohn's disease.
Protein deglycase DJ-1, also known as Parkinson disease protein 7, is a protein which in humans is encoded by the PARK7 gene.
Probable G-protein coupled receptor 37 is a protein that in humans is encoded by the GPR37 gene.
Synphilin-1 is a protein that in humans is encoded by the SNCAIP gene. SNCAIP stands for "synuclein, alpha interacting protein" and can be signified by SNCAP_HUMAN, synphilin 1, synuclein, alpha interacting protein (synphilin), and SYPH1.
E3 ubiquitin-protein ligase SMURF1 is an enzyme that in humans is encoded by the SMURF1 gene. The SMURF1 Gene encodes a protein with a size of 757 amino acids and the molecular mass of this protein is 86114 Da.
Ubiquitin-specific-processing protease 7 (USP7), also known as ubiquitin carboxyl-terminal hydrolase 7 or herpesvirus-associated ubiquitin-specific protease (HAUSP), is an enzyme that in humans is encoded by the USP7 gene.
Ubiquitin carboxyl-terminal hydrolase isozyme L5 is an enzyme that in humans is encoded by the UCHL5 gene.
Ubiquitin carboxyl-terminal hydrolase isozyme L3 is an enzyme that in humans is encoded by the UCHL3 gene.
BRCA1 associated protein-1 is a deubiquitinating enzyme that in humans is encoded by the BAP1 gene. BAP1 encodes an 80.4 kDa nuclear-localizing protein with a ubiquitin carboxy-terminal hydrolase (UCH) domain that gives BAP1 its deubiquitinase activity. Recent studies have shown that BAP1 and its fruit fly homolog, Calypso, are members of the polycomb-group proteins (PcG) of highly conserved transcriptional repressors required for long-term silencing of genes that regulate cell fate determination, stem cell pluripotency, and other developmental processes.
Ubiquitin carboxyl-terminal hydrolase 20 is an enzyme that in humans is encoded by the USP20 gene.
Parkinson's disease (PD) is a degenerative disorder of the central nervous system. Most people with PD have idiopathic Parkinson's disease. A small proportion of cases, however, can be attributed to known genetic factors. Other factors such as environmental toxins, herbicides, pesticides, and fungicides, have been associated with the risk of developing PD, but no causal relationships have been proven.
Gene therapy in Parkinson's disease consists of the creation of new cells that produce a specific neurotransmitter (dopamine), protect the neural system, or the modification of genes that are related to the disease. Then these cells are transplanted to a patient with the disease. There are different kinds of treatments that focus on reducing the symptoms of the disease but currently there is no cure.