THOC4 Antibody - #DF4664

Export adapter involved in nuclear export of spliced and unspliced mRNA. Binds mRNA which is thought to be transferred to the NXF1-NXT1 heterodimer for export (TAP/NFX1 pathway). Component of the TREX complex which is thought to couple mRNA transcription, processing and nuclear export, and specifically associates with spliced mRNA and not with unspliced pre-mRNA. TREX is recruited to spliced mRNAs by a transcription-independent mechanism, binds to mRNA upstream of the exon-junction complex (EJC) and is recruited in a splicing- and cap-dependent manner to a region near the 5' end of the mRNA where it functions in mRNA export to the cytoplasm. TREX recruitment occurs via an interaction between ALYREF/THOC4 and the cap-binding protein NCBP1. The TREX complex is essential for the export of Kaposi's sarcoma-associated herpesvirus (KSHV) intronless mRNAs and infectious virus production; ALYREF/THOC4 mediates the recruitment of the TREX complex to the intronless viral mRNA. Required for TREX complex assembly and for linking DDX39B to the cap-binding complex (CBC). In conjunction with THOC5 functions in NXF1-NXT1 mediated nuclear export of HSP70 mRNA; both proteins enhance the RNA binding activity of NXF1 and are required for NXF1 localization to the nuclear rim. Involved in the nuclear export of intronless mRNA; proposed to be recruited to intronless mRNA by ATP-bound DDX39B. Involved in transcription elongation and genome stability. Involved in mRNA export of C5-methylcytosine (m5C)-containing mRNAs: specifically recognizes and binds m5C mRNAs and mediates their nucleo-cytoplasmic shuttling.

Acts as chaperone and promotes the dimerization of transcription factors containing basic leucine zipper (bZIP) domains and thereby promotes transcriptional activation.

Arg-204 is dimethylated, probably to asymmetric dimethylarginine. Arginine methylation reduces RNA binding.

Citrullinated by PADI4.

Nucleus. Nucleus speckle. Cytoplasm.
Note: Colocalizes with the core EJC, ALYREF/THOC4, NXF1 and DDX39B in the nucleus and nuclear speckles. Travels to the cytoplasm as part of the exon junction complex (EJC) bound to mRNA (PubMed:19324961). Localizes to regions surrounding nuclear speckles known as perispeckles in which TREX complex assembly seems to occur (PubMed:23826332).

Expressed in a wide variety of cancer types.

Homomultimer. Is part of several complexes involved in mRNA processing and export. Component of the transcription/export (TREX) complex at least composed of ALYREF/THOC4, DDX39B, SARNP/CIP29, CHTOP and the THO subcomplex; TREX seems to have a dynamic structure involving ATP-dependent remodeling; in the complex interacts (via C-terminus) directly with DDX39B and interacts directly with THOC1 and THOC2. Found in mRNA splicing-dependent exon junction complexes (EJC). Identified in the spliceosome C complex. Found in a mRNP complex with UPF3A and UPF3B. Interacts with RBM8A, NCBP1, THOC5, LEF1, RUNX1, EIF4A3, RNPS1, SRRM1, IWS1 and EXOSC1. Interacts with RBM15B. Interacts with NXF1; the interaction is direct.

(Microbial infection) Interacts with human Kaposi's sarcoma-associated herpesvirus (HHV-8) ORF57 protein; this interaction allows efficient export of HHV-8 early and late intronless transcripts.

(Microbial infection) Interacts with HHV-1 ICP27 protein; this interaction recruits ALYREF to viral replication compartments and probably directs viral mRNA to the TAP/NFX1 pathway.

Belongs to the ALYREF family.