Menu
Home
People
Places
Arts
History
Plants & Animals
Science
Life & Culture
Technology
Reference.org
Exon junction complex
open-in-new
<p>An exon junction complex (EJC) is a <a href="/facts/Multiprotein_complex/GW11Ee34">protein complex</a> which forms on a <a href="/facts/Precursor_mRNA/4UXtKPHw">pre-messenger RNA</a> strand at the junction of two <a href="/facts/Exon/8KWJtLuN">exons</a> which have been joined together during <a href="/facts/RNA_splicing/a2QEvCRI">RNA splicing</a>. The EJC has major influences on <a href="/facts/DNA_Translation/JcPC1rth">translation</a>, <a href="/facts/MRNA_surveillance/KKMp6Rpz">surveillance</a>, localization of the spliced <a href="/facts/MRNA/oUL6qxQn">mRNA</a>, and <a href="/facts/N6-Methyladenosine/HHdwLkJP"> m6A methylation</a>. It is first deposited onto mRNA during splicing and is then transported into the <a href="/facts/Cytoplasm/Wa0sE6xf">cytoplasm</a>. 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 <a href="/facts/Protein/Jxmagu3E">protein</a> <a href="/facts/Eukaryote/SkwyPLMA">eukaryotic</a> <a href="/facts/Initiation_factor/WJq3xTxn">initiation factor</a> 4A-III (<a href="/facts/EIF4A3/UEP3aYkz">eIF4A-III</a>; a <a href="/facts/DEAD_box/Io5dNsC6">DEAD-box</a> <a href="/facts/RNA/HxPeNfNj">RNA</a> <a href="/facts/Helicase/IemubWzR">helicase</a>) bound to an adenosine triphosphate (<a href="/facts/Adenosine_triphosphate/nB9bwgcU">ATP</a>) analog, as well as the additional proteins <a href="/facts/MAGOH/74YNKlDK">Magoh</a> and <a href="/facts/Y14_(gene)/I0XjRqKt">Y14</a>. The binding of these proteins to nuclear speckled domains has been measured recently and it may be regulated by <a href="/facts/PI3K/AKT/mTOR_pathway/bgWlgxQJ">PI3K/AKT/mTOR signaling pathways</a>. 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. </p>