THOC1

HPR1 is part of the TREX (transcription/export) complex, which includes TEX1, THO2, ALY, and UAP56.

Full Name

THO Complex 1

Function

Required for efficient export of polyadenylated RNA. Acts as component of the THO subcomplex of the TREX complex which is thought to couple mRNA transcription, processing and nuclear export, and which 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 via the TAP/NFX1 pathway. The TREX complex is essential for the export of Kaposi's sarcoma-associated herpesvirus (KSHV) intronless mRNAs and infectious virus production. Regulates transcriptional elongation of a subset of genes. Involved in genome stability by preventing co-transcriptional R-loop formation.
Participates in an apoptotic pathway which is characterized by activation of caspase-6, increases in the expression of BAK1 and BCL2L1 and activation of NF-kappa-B. This pathway does not require p53/TP53, nor does the presence of p53/TP53 affect the efficiency of cell killing. Activates a G2/M cell cycle checkpoint prior to the onset of apoptosis. Apoptosis is inhibited by association with RB1.

Biological Process

Biological Process apoptotic processSource:UniProtKB1 Publication
Biological Process mRNA export from nucleusSource:UniProtKB1 Publication
Biological Process mRNA processingSource:UniProtKB-KW
Biological Process negative regulation of DNA damage checkpointSource:UniProtKB1 Publication
Biological Process negative regulation of isotype switching to IgA isotypesSource:UniProtKB
Biological Process positive regulation of DNA-templated transcription, elongationSource:UniProtKB1 Publication
Biological Process regulation of DNA recombinationSource:UniProtKB1 Publication
Biological Process regulation of DNA-templated transcription elongationSource:UniProtKB1 Publication
Biological Process replication fork processingSource:UniProtKB1 Publication
Biological Process RNA processingSource:ProtInc1 Publication
Biological Process RNA splicingSource:UniProtKB-KW
Biological Process signal transductionSource:InterPro
Biological Process viral mRNA export from host cell nucleusSource:UniProtKB1 Publication

Cellular Location

Isoform 1
Nucleus speckle
Nucleus, nucleoplasm
Nucleus matrix
Cytoplasm
Can shuttle between the nucleus and cytoplasm. Nuclear localization is required for induction of apoptotic cell death. Translocates to the cytoplasm during the early phase of apoptosis execution.
Isoform 2
Cytoplasm

PTM

Expression is altered specifically during apoptosis and is accompanied by the appearance of novel forms with smaller apparent molecular mass.
Polyubiquitinated, leading to proteasomal degradation; probably involves NEDD4.