Protein CASC3 is a protein that in humans is encoded by the CASC3 gene. [5] [6] [7]
Protein CASC3 is a protein that in humans is encoded by the CASC3 gene. [5] [6] [7]
The product of this gene is a core component of the exon junction complex (EJC), a protein complex that is deposited on spliced mRNAs at exon-exon junctions and functions in nonsense-mediated mRNA decay (NMD). The encoded protein binds RNA and interacts with two other EJC core components. It is predominantly located in the cytoplasm, but shuttles into the nucleus where it localizes to nuclear speckles. [7]
Alternative splicing, or alternative RNA splicing, or differential splicing, is an alternative splicing process during gene expression that allows a single gene to code for multiple proteins. In this process, particular exons of a gene may be included within or excluded from the final, processed messenger RNA (mRNA) produced from that gene. This means the exons are joined in different combinations, leading to different (alternative) mRNA strands. Consequently, the proteins translated from alternatively spliced mRNAs will contain differences in their amino acid sequence and, often, in their biological functions.
RNA-binding proteins are proteins that bind to the double or single stranded RNA in cells and participate in forming ribonucleoprotein complexes. RBPs contain various structural motifs, such as RNA recognition motif (RRM), dsRNA binding domain, zinc finger and others. They are cytoplasmic and nuclear proteins. However, since most mature RNA is exported from the nucleus relatively quickly, most RBPs in the nucleus exist as complexes of protein and pre-mRNA called heterogeneous ribonucleoprotein particles (hnRNPs). RBPs have crucial roles in various cellular processes such as: cellular function, transport and localization. They especially play a major role in post-transcriptional control of RNAs, such as: splicing, polyadenylation, mRNA stabilization, mRNA localization and translation. Eukaryotic cells express diverse RBPs with unique RNA-binding activity and protein–protein interaction. According to the Eukaryotic RBP Database (EuRBPDB), there are 2961 genes encoding RBPs in humans. During evolution, the diversity of RBPs greatly increased with the increase in the number of introns. Diversity enabled eukaryotic cells to utilize RNA exons in various arrangements, giving rise to a unique RNP (ribonucleoprotein) for each RNA. Although RBPs have a crucial role in post-transcriptional regulation in gene expression, relatively few RBPs have been studied systematically.
Nonsense-mediated mRNA decay (NMD) is a surveillance pathway that exists in all eukaryotes. Its main function is to reduce errors in gene expression by eliminating mRNA transcripts that contain premature stop codons. Translation of these aberrant mRNAs could, in some cases, lead to deleterious gain-of-function or dominant-negative activity of the resulting proteins.
RNA-binding protein 8A is a protein that in humans is encoded by the RBM8A gene.
Regulator of nonsense transcripts 1 is a protein that in humans is encoded by the UPF1 gene.
Tyrosine-protein kinase 6 is an enzyme that in humans is encoded by the PTK6 gene.
Heterogeneous nuclear ribonucleoprotein F is a protein that in humans is encoded by the HNRNPF gene.
Regulator of nonsense transcripts 2 is a protein that in humans is encoded by the UPF2 gene.
Double-stranded RNA-binding protein Staufen homolog 1 is a protein that in humans is encoded by the STAU1 gene.
Regulator of nonsense transcripts 3B is a protein that in humans is encoded by the UPF3B gene.
Aly/REF export factor, also known as THO complex subunit 4 is a protein that in humans is encoded by the ALYREF gene.
Protein mago nashi homolog is a protein that in humans is encoded by the MAGOH gene.
Far upstream element-binding protein 2 is a protein that in humans is encoded by the KHSRP gene.
Eukaryotic initiation factor 4A-III is a protein that in humans is encoded by the EIF4A3 gene.
Regulator of nonsense transcripts 3A is a protein that in humans is encoded by the UPF3A gene.
Metadherin, also known as protein LYRIC or astrocyte elevated gene-1 protein (AEG-1) is a protein that in humans is encoded by the MTDH gene.
mRNA surveillance mechanisms are pathways utilized by organisms to ensure fidelity and quality of messenger RNA (mRNA) molecules. There are a number of surveillance mechanisms present within cells. These mechanisms function at various steps of the mRNA biogenesis pathway to detect and degrade transcripts that have not properly been processed.
An exon junction complex (EJC) is a protein complex which forms on a pre-messenger RNA strand at the junction of two exons which have been joined together during RNA splicing. The EJC has major influences on translation, surveillance and localization of the spliced mRNA. It is first deposited onto mRNA during splicing and is then transported into the cytoplasm. There it plays a major role in post-transcriptional regulation of mRNA. It is believed that exon junction complexes provide a position-specific memory of the splicing event. The EJC consists of a stable heterotetramer core, which serves as a binding platform for other factors necessary for the mRNA pathway. The core of the EJC contains the protein eukaryotic initiation factor 4A-III bound to an adenosine triphosphate (ATP) analog, as well as the additional proteins Magoh and Y14. The binding of these proteins to nuclear speckled domains has been measured recently and it may be regulated by PI3K/AKT/mTOR signaling pathways. In order for the binding of the complex to the mRNA to occur, the eIF4AIII factor is inhibited, stopping the hydrolysis of ATP. This recognizes EJC as an ATP dependent complex. EJC also interacts with a large number of additional proteins; most notably SR proteins. These interactions are suggested to be important for mRNA compaction. The role of EJC in mRNA export is controversial.
In molecular biology, the Btz domain is a protein domain found on CASC3 which is also known as Barentsz (Btz). CASC3 is a component of the EJC which is a complex that is involved in post-transcriptional regulation of mRNA in metazoa. The complex is formed by the association of four proteins, mRNA, and ATP. This domain wraps around eIF4AIII and stacks against the 5' nucleotide.
WRAP53 is a gene implicated in cancer development. The name was coined in 2009 to describe the dual role of this gene, encoding both an antisense RNA that regulates the p53 tumor suppressor and a protein involved in DNA repair, telomere elongation and maintenance of nuclear organelles Cajal bodies.
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