Cap binding complex
The
5' cap of eukaryotic messenger RNA
is bound at all times by various cap-binding complexes (CBCs).
Nuclear cap-binding complex
In the nucleus, freshly transcribed mRNA molecules are bound on the 5' cap by the
nonsense mediated decay.[1]
Cytoplasmic cap-binding complex
After the first round of translation ("pioneer round"), CBC20/80 is replaced by the
translation initiation factor eIF4E.[2] The eIF4F complex (eIF4E, eIF4G and eIF4A) then regulates translation in response to the state of the cell via its phosphorylation state and again protects the message from decapping.[3]
Decapping complex
When translationally repressed or marked for decay by various mechanisms the 5' cap is bound by the mRNA decapping enzyme
XRN1, and others. The decapping enzyme removes the 5' cap leading to destruction of the message.[4]
References
External links
- nuclear+cap-binding+protein+complex at the U.S. National Library of Medicine Medical Subject Headings (MeSH)