Small ubiquitin-related modifier 1 is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

that in humans is encoded by the ''SUMO1''

gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...

Function

This gene encodes a protein that is a member of the

SUMO is a form of competitive full-contact wrestling where a ''rikishi'' (wrestler) attempts to force his opponent out of a circular ring (''dohyō'') or into touching the ground with any body part other than the soles of his feet (usually by th ...

(small ubiquitin-like modifier) protein family. It is a

ubiquitin-like protein Ubiquitin-like proteins (UBLs) are a family of small proteins involved in post-translational modification of other proteins in a cell (biology), cell, usually with a regulatory protein, regulatory function. The UBL protein family derives its name ...

and functions in a manner similar to

ubiquitin Ubiquitin is a small (8.6 kDa) regulatory protein found in most tissues of eukaryotic organisms, i.e., it is found ''ubiquitously''. It was discovered in 1975 by Gideon Goldstein and further characterized throughout the late 1970s and 19 ...

in that it is bound to target proteins as part of a

post-translational modification In molecular biology, post-translational modification (PTM) is the covalent process of changing proteins following protein biosynthesis. PTMs may involve enzymes or occur spontaneously. Proteins are created by ribosomes, which translation (biolog ...

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 The C-terminus (also known as the carboxyl-terminus, carboxy-terminus, C-terminal tail, carboxy tail, C-terminal end, or COOH-terminus) is the end of an amino acid chain (protein or polypeptide), terminated by a free carboxyl group (-COOH). When t ...

have been cleaved off. Several

pseudogene Pseudogenes are nonfunctional segments of DNA that resemble functional genes. Pseudogenes can be formed from both protein-coding genes and non-coding genes. In the case of protein-coding genes, most pseudogenes arise as superfluous copies of fun ...

s have been reported for this gene. Alternate transcriptional

splice variant Alternative splicing, alternative RNA splicing, or differential splicing, is an alternative splicing process during gene expression that allows a single gene to produce different splice variants. For example, some exons of a gene may be included ...

s encoding different

isoform A protein isoform, or "protein variant", is a member of a set of highly similar proteins that originate from a single gene and are the result of genetic differences. While many perform the same or similar biological roles, some isoforms have uniqu ...

s have been characterized. Most cleft genes have a

sumoylation In molecular biology, SUMO (Small Ubiquitin-like Modifier) proteins are a family of small proteins that are covalently attached to and detached from other proteins in cells to modify their function. This process is called SUMOylation (pronounced ...

component. Analysis of chromosomal anomalies in patients has led to the identification and confirmation of SUMO1 as a

cleft lip and palate A cleft lip contains an opening in the upper lip that may extend into the nose. The opening may be on one side, both sides, or in the middle. A cleft palate occurs when the palate (the roof of the mouth) contains an opening into the nose. The ...

locus.

Interactions

Small ubiquitin-related modifier 1 has been shown to interact with: *

C22orf25 Transport and golgi organization 2 homolog (TANGO2) also known as chromosome 22 open reading frame 25 (C22orf25) is a protein that in humans is encoded by the TANGO2 gene. The function of C22orf25 is not currently known. It is characterized by ...

, * DAXX, * DNMT3B, *

P53 p53, also known as tumor protein p53, cellular tumor antigen p53 (UniProt name), or transformation-related protein 53 (TRP53) is a regulatory transcription factor protein that is often mutated in human cancers. The p53 proteins (originally thou ...

, * PIAS1, * PML, * SAE2, * SP1, * TDG, * TNFRSF1A, * TNFRSF6, *

TOP2A DNA topoisomerase IIα is a human enzyme encoded by the ''TOP2A'' gene. Topoisomerase IIα relieves topological DNA stress during transcription, condenses chromosomes, and separates chromatids. It catalyzes the transient breaking and rejoining o ...

, * TOP2B, and *

UBE2I 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 ...

Role in the heart

Heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome caused by an impairment in the heart's ability to Cardiac cycle, fill with and pump blood. Although symptoms vary based on which side of the heart is affected, HF ...

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 SUMO 1 is a key component in cardiac function, since it helps regulate calcium homeostasis in the

mitochondria A mitochondrion () is an organelle found in the cells of most eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is us ...

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 The sarcoplasmic reticulum (SR) is a membrane-bound structure found within muscle cells that is similar to the smooth endoplasmic reticulum in other cells. The main function of the SR is to store calcium ions (Ca2+). Calcium ion levels are kep ...

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. 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.

As a drug target

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. Furthermore, overexpression of SUMO 1 resulted in accelerated calcium uptake, providing further evidence regarding its importance in maintaining adequate calcium levels in heart cells.

References

External links

* * {{PDB Gallery, geneid=7341