Details

Autor(en) / Beteiligte

• Rambout, Xavier
• Maquat, Lynne E.

Titel

NCBP3: A Multifaceted Adaptive Regulator of Gene Expression

Ist Teil von

• Trends in biochemical sciences (Amsterdam. Regular ed.), 2021-02, Vol.46 (2), p.87-96

Ort / Verlag

England: Elsevier Ltd

Erscheinungsjahr

2021

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• Eukaryotic cells have divided the steps of gene expression between their nucleus and cytoplasm. Protein-encoding genes generate mRNAs in the nucleus and mRNAs undergo transport to the cytoplasm for the purpose of producing proteins. Cap-binding protein (CBP)20 and its binding partner CBP80 have been thought to constitute the cap-binding complex (CBC) that is acquired co-transcriptionally by the precursors of all mRNAs. However, this principle has recently been challenged by studies of nuclear cap-binding protein 3 (NCBP3). Here we submit how NCBP3, as an alternative to CBP20, an accessory to the canonical CBP20−CBP80 CBC, and/or an RNA-binding protein – possibly in association with the exon-junction complex (EJC) – expands the capacity of cells to regulate gene expression. Conventional views of nuclear cap-binding proteins (NCBPs) have recently been challenged. There exist different opinions on whether NCBP3 is an alternative to cap-binding protein (CBP)20 at the 5′ m7G cap of pre-mRNAs, binds to CBP80 and arsenite resistance protein 2 (ARS2) in a cap-bound CBP20–CBP80–ARS2 complex, and/or binds to RNA – possibly in association with exon-junction complexes.We predict that mutually exclusive binding of NCBP3 to m7G caps, the cap-binding complex (CBC), and/or RNA is regulated by NCBP3’s noncanonical RNA-recognition motif (RRM) and a putative α3-helix that resides distal to the RRM.NCBP3 may regulate various steps of RNA metabolism: mRNA export from the nucleus, mRNA translation, and possibly pre-mRNA splicing, pre-mRNA 3′-end formation, and noncanonical splicing of cytoplasmic mRNAs.NCBP3 function appears to become critical when cells are stressed, such as during viral infection and when cells are transformed to become cancer cells.