40S ribosomal protein S25 (eS25) is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
that in humans is encoded by the ''RPS25''
gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
.
Ribosomes
Ribosomes ( ) are macromolecular machines, found within all cells, that perform biological protein synthesis (mRNA translation). Ribosomes link amino acids together in the order specified by the codons of messenger RNA (mRNA) molecules to f ...
are cellular macromolecules that
catalyze
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
protein synthesis
Protein biosynthesis (or protein synthesis) is a core biological process, occurring inside Cell (biology), cells, homeostasis, balancing the loss of cellular proteins (via Proteolysis, degradation or Protein targeting, export) through the product ...
across all kingdoms of life. The eukaryotic ribosome consists of a
small 40S subunit and a
large 60S subunit. Together these subunits are composed of 4
RNA
Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes. RNA and deoxyribonucleic acid ( DNA) are nucleic acids. Along with lipids, proteins, and carbohydra ...
species and approximately 80 distinct proteins. The RPS25 gene encodes the eukaryote-specific
ribosomal protein
A ribosomal protein (r-protein or rProtein) is any of the proteins that, in conjunction with rRNA, make up the ribosomal subunits involved in the cellular process of translation. ''E. coli'', other bacteria and Archaea have a 30S small subunit an ...
eS25 that is a component of the 40S subunit. As is typical for genes encoding ribosomal proteins, there are multiple processed
pseudogenes
Pseudogenes are nonfunctional segments of DNA that resemble functional genes. Most arise as superfluous copies of functional genes, either directly by DNA duplication or indirectly by reverse transcription of an mRNA transcript. Pseudogenes are ...
of this gene dispersed through the genome.
Interactions
Besides the interactions that position eS25 at its location in the E site region of the 40S ribosomal subunit, eS25 has been suggested to interact with other cellular proteins. One study has found that eS25 interacts with
MDM2 as part of a regulatory feedback loop that stabilizes
p53
p53, also known as Tumor protein P53, cellular tumor antigen p53 (UniProt name), or transformation-related protein 53 (TRP53) is a regulatory protein that is often mutated in human cancers. The p53 proteins (originally thought to be, and often s ...
.
Additionally, eS25 has been shown to interact with
CDC5L
Cell division cycle 5-like protein is a protein that in humans is encoded by the ''CDC5L'' gene.
Function
The protein encoded by this gene shares a significant similarity with ''Schizosaccharomyces pombe'' cdc5 gene product, which is a cell cyc ...
.
Function
As a ribosomal protein, eS25 likely plays a role in general protein synthesis; however, the RPS25 gene is non-essential for cellular viability in budding yeast and in select mammalian cell lines, implying that it is not essential for eukaryotic protein synthesis.
Studies have implicated eS25 in the control of several specialized forms of translation, including that mediated by viral
IRESs.
See also
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Eukaryotic translation
Eukaryotic translation is the biological process by which messenger RNA is translated into proteins in eukaryotes. It consists of four phases: gene translation, elongation, termination, and recapping.
Initiation
Translation initiation is the pr ...
*
40S ribosomal subunit
*
IRES
References
Further reading
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Ribosomal proteins