Small ubiquitin-related modifier 1 is a protein that in humans is encoded by the SUMO1 gene. [5] [6]
This gene encodes a protein that is a member of the SUMO (small ubiquitin-like modifier) protein family. It is a ubiquitin-like protein and functions in a manner similar to ubiquitin in that it is bound to target proteins as part of a post-translational modification system. However, unlike ubiquitin, which is primarily associated with targeting proteins for proteasomal degradation, SUMO1 is involved in a variety of cellular processes, such as nuclear transport, transcriptional regulation, apoptosis, and protein stability. It is not active until the last four amino acids of the carboxy-terminus have been cleaved off. Several pseudogenes have been reported for this gene. Alternate transcriptional splice variants encoding different isoforms have been characterized. [7]
Most cleft genes have a sumoylation component. [8] Analysis of chromosomal anomalies in patients has led to the identification and confirmation of SUMO1 as a cleft lip and palate locus. [9]
Small ubiquitin-related modifier 1 has been shown to interact with:
Heart failure is a process by which the heart’s pumping ability is significantly weakened, so that the body is unable to get adequate circulation. A weakened heart results in symptoms of fatigue, decreased exercise tolerance and shortness of breath. Patients with heart failure have a significantly increased risk of death compared to people with normal heart function. Heart failure is a major public health concern, as its incidence is on the rise worldwide, and is a leading cause of death in developed nations [27]
SUMO 1 is a key component in cardiac function, since it helps regulate calcium homeostasis in the mitochondria of heart cells. SUMO 1 is associated with another essential cardiac protein called sarco/endoplasmic reticulum Ca2+ ATPase, or SERCA2A. SERCA is a transmembrane protein located in the sarcoplasmic reticulum of cardiac cells. Its main function is to regulate the discharge and uptake of intracellular calcium between the cytosol and the lumen of the sarcoplasmic reticulum. Calcium is an essential factor for the development of cardiac myocyte contraction and relaxation. Thus, the management of intracellular calcium homeostasis by SERCA2A is critical for overall cardiac performance. [28] Normally, SUMO 1 activates and stabilizes SERCA2A by binding at lysine resides 480 and 585. The interaction between SUMO 1 and SERCA2A is crucial for regulating calcium levels inside cardiac myocytes. Reduction in SUMO 1 protein reduces SERCA2A, and thus efficient calcium handling in patients with failing hearts. [29]
SUMO 1 may be an important therapeutic target to help improve cardiac performance in patients with heart failure. In a mouse model, the introduction of SUMO 1 through gene therapy was associated with improved activity of SERCA2A, which resulted in improved cardiac function through an augmentation of cardiac contractility. [29] Furthermore, overexpression of SUMO 1 resulted in accelerated calcium uptake, providing further evidence regarding its importance in maintaining adequate calcium levels in heart cells. [29]
Phospholamban, also known as PLN or PLB, is a micropeptide protein that in humans is encoded by the PLN gene. Phospholamban is a 52-amino acid integral membrane protein that regulates the calcium (Ca2+) pump in cardiac muscle cells.
Apoptosis signal-regulating kinase 1 (ASK1) also known as mitogen-activated protein kinase 5 (MAP3K5) is a member of MAP kinase family and as such a part of mitogen-activated protein kinase pathway. It activates c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinases in a Raf-independent fashion in response to an array of stresses such as oxidative stress, endoplasmic reticulum stress and calcium influx. ASK1 has been found to be involved in cancer, diabetes, rheumatoid arthritis, cardiovascular and neurodegenerative diseases.
Promyelocytic leukemia protein (PML) is the protein product of the PML gene. PML protein is a tumor suppressor protein required for the assembly of a number of nuclear structures, called PML-nuclear bodies, which form amongst the chromatin of the cell nucleus. These nuclear bodies are present in mammalian nuclei, at about 1 to 30 per cell nucleus. PML-NBs are known to have a number of regulatory cellular functions, including involvement in programmed cell death, genome stability, antiviral effects and controlling cell division. PML mutation or loss, and the subsequent dysregulation of these processes, has been implicated in a variety of cancers.
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.
Ryanodine receptor 2 (RYR2) is one of a class of ryanodine receptors and a protein found primarily in cardiac muscle. In humans, it is encoded by the RYR2 gene. In the process of cardiac calcium-induced calcium release, RYR2 is the major mediator for sarcoplasmic release of stored calcium ions.
RAN binding protein 2 (RANBP2) is protein which in humans is encoded by the RANBP2 gene. It is also known as nucleoporin 358 (Nup358) since it is a member nucleoporin family that makes up the nuclear pore complex. RanBP2 has a mass of 358 kDa.
NEDD8 is a protein that in humans is encoded by the NEDD8 gene. This ubiquitin-like (UBL) protein becomes covalently conjugated to a limited number of cellular proteins, in a process called NEDDylation similar to ubiquitination. Human NEDD8 shares 60% amino acid sequence identity to ubiquitin. The primary known substrates of NEDD8 modification are the cullin subunits of cullin-based E3 ubiquitin ligases, which are active only when NEDDylated. Their NEDDylation 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.
Homeodomain-interacting protein kinase 2 is an enzyme that in humans is encoded by the HIPK2 gene. HIPK2 can be categorized as a Serine/Threonine Protein kinase, specifically one that interacts with homeodomain transcription factors. It belongs to a family of protein kinases known as the DYRK kinases. Within this family HIPK2 belongs to a group of homeodomain-interacting protein kinases (HIPKs), including HIPK1 and HIPK3. HIPK2 can be found in a wide variety of species and its functions in gene expression and apoptosis are regulated by several different mechanisms.
Small ubiquitin-related modifier 2 is a protein that in humans is encoded by the SUMO2 gene.
26S proteasome non-ATPase regulatory subunit 4, also as known as 26S Proteasome Regulatory Subunit Rpn10, is an enzyme that in humans is encoded by the PSMD4 gene. This protein is one of the 19 essential subunits that contributes to the complete assembly of 19S proteasome complex.
Ran GTPase-activating protein 1 is an enzyme that in humans is encoded by the RANGAP1 gene.
Small ubiquitin-related modifier 3 is a protein that in humans is encoded by the SUMO3 gene.
Sorcin is a protein that in humans is encoded by the SRI gene.
SUMO1/sentrin/SMT3 specific peptidase 3, also known as SENP3, is a protein which in humans is encoded by the SENP3 gene.
NEDD8 ultimate buster 1 is a protein that in humans is encoded by the NUB1 gene.
Sentrin-specific protease 1 is an enzyme that in humans is encoded by the SENP1 gene.
Sentrin-specific protease 6 is an enzyme that in humans is encoded by the SENP6 gene.
Sentrin-specific protease 2 is an enzyme that in humans is encoded by the SENP2 gene.
NEDD8-conjugating enzyme Ubc12 is a protein that in humans is encoded by the UBE2M gene.
Ubiquitin-like proteins (UBLs) are a family of small proteins involved in post-translational modification of other proteins in a cell, usually with a regulatory function. The UBL protein family derives its name from the first member of the class to be discovered, ubiquitin (Ub), best known for its role in regulating protein degradation through covalent modification of other proteins. Following the discovery of ubiquitin, many additional evolutionarily related members of the group were described, involving parallel regulatory processes and similar chemistry. UBLs are involved in a widely varying array of cellular functions including autophagy, protein trafficking, inflammation and immune responses, transcription, DNA repair, RNA splicing, and cellular differentiation.