InnateDB: Systems Biology of the Innate Immune Response

Homo sapiens Protein: NCBP2

Summary

InnateDB Protein

IDBP-387140.5

Last Modified

2014-10-13 [Report errors or provide feedback]

Gene Symbol

NCBP2

Protein Name

nuclear cap binding protein subunit 2, 20kDa

Synonyms

CBC2; CBP20; NIP1;

Species

Homo sapiens

Ensembl Protein

ENSP00000412785

InnateDB Gene

IDBG-71402 (NCBP2)

Protein Structure

UniProt Annotation

Function

Component of the cap-binding complex (CBC), which binds co-transcriptionally to the 5' cap of pre-mRNAs and is involved in various processes such as pre-mRNA splicing, translation regulation, nonsense-mediated mRNA decay, RNA-mediated gene silencing (RNAi) by microRNAs (miRNAs) and mRNA export. The CBC complex is involved in mRNA export from the nucleus via its interaction with ALYREF/THOC4/ALY, leading to the recruitment of the mRNA export machinery to the 5' end of mRNA and to mRNA export in a 5' to 3' direction through the nuclear pore. The CBC complex is also involved in mediating U snRNA and intronless mRNAs export from the nucleus. The CBC complex is essential for a pioneer round of mRNA translation, before steady state translation when the CBC complex is replaced by cytoplasmic cap-binding protein eIF4E. The pioneer round of mRNA translation mediated by the CBC complex plays a central role in nonsense-mediated mRNA decay (NMD), NMD only taking place in mRNAs bound to the CBC complex, but not on eIF4E-bound mRNAs. The CBC complex enhances NMD in mRNAs containing at least one exon-junction complex (EJC) via its interaction with UPF1, promoting the interaction between UPF1 and UPF2. The CBC complex is also involved in 'failsafe' NMD, which is independent of the EJC complex, while it does not participate in Staufen-mediated mRNA decay (SMD). During cell proliferation, the CBC complex is also involved in microRNAs (miRNAs) biogenesis via its interaction with SRRT/ARS2, thereby being required for miRNA- mediated RNA interference. The CBC complex also acts as a negative regulator of PARN, thereby acting as an inhibitor of mRNA deadenylation. In the CBC complex, NCBP2/CBP20 recognizes and binds capped RNAs (m7GpppG-capped RNA) but requires NCBP1/CBP80 to stabilize the movement of its N-terminal loop and lock the CBC into a high affinity cap-binding state with the cap structure. {ECO:0000269PubMed:11551508, ECO:0000269PubMed:15361857, ECO:0000269PubMed:17190602, ECO:0000269PubMed:17363367, ECO:0000269PubMed:17873884, ECO:0000269PubMed:18369367, ECO:0000269PubMed:19632182}.

Subcellular Localization

Nucleus {ECO:0000269PubMed:8601613}. Cytoplasm {ECO:0000269PubMed:8601613}.

Disease Associations

Tissue Specificity

Comments

Interactions

Number of Interactions

This gene and/or its encoded proteins are associated with 28 experimentally validated interaction(s) in this database.

Experimentally validated
Total	28 [view]
Protein-Protein	25 [view]
Protein-DNA	3 [view]
Protein-RNA	0
DNA-DNA	0
RNA-RNA	0
DNA-RNA	0

Gene Ontology

Molecular Function

Accession	GO Term
GO:0000166	nucleotide binding
GO:0000339	RNA cap binding
GO:0000340	RNA 7-methylguanosine cap binding
GO:0003676	nucleic acid binding
GO:0005515	protein binding
GO:0044822	poly(A) RNA binding

Biological Process

GO:0000184	nuclear-transcribed mRNA catabolic process, nonsense-mediated decay
GO:0000387	spliceosomal snRNP assembly
GO:0000398	mRNA splicing, via spliceosome
GO:0006366	transcription from RNA polymerase II promoter
GO:0006368	transcription elongation from RNA polymerase II promoter
GO:0006369	termination of RNA polymerase II transcription
GO:0006370	7-methylguanosine mRNA capping
GO:0006406	mRNA export from nucleus
GO:0006408	snRNA export from nucleus
GO:0006446	regulation of translational initiation
GO:0008334	histone mRNA metabolic process
GO:0008380	RNA splicing
GO:0010467	gene expression
GO:0016032	viral process
GO:0016070	RNA metabolic process
GO:0016071	mRNA metabolic process
GO:0031047	gene silencing by RNA
GO:0031124	mRNA 3'-end processing
GO:0034660	ncRNA metabolic process
GO:0045292	mRNA cis splicing, via spliceosome
GO:0046833	positive regulation of RNA export from nucleus
GO:0050434	positive regulation of viral transcription