Related Experiment Video

Updated: Jun 26, 2026

In vivo and in vitro Studies of Adaptor-clathrin Interaction
17:14

In vivo and in vitro Studies of Adaptor-clathrin Interaction

Published on: January 26, 2011

Adaptor Aly and co-adaptor Thoc5 function in the Tap-p15-mediated nuclear export of HSP70 mRNA

Jun Katahira1, Hitomi Inoue, Ed Hurt

  • 1Biomolecular Dynamics Laboratory, Graduate School of Frontier Biosciences, Osaka University, Yamadaoka, Suita, Osaka, Japan Japan. katahira@anat3.med.osaka-u.ac.jp

The EMBO Journal
|January 24, 2009
PubMed

Insights

Thymus and abnormal proliferation (Thoc5) protein acts as a specific adaptor for nuclear mRNA export, distinct from bulk mRNA export pathways. It cooperates with the Tap-p15 receptor to regulate specific messenger RNA (mRNA) transport.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Genetics

Background:

  • Nuclear export of messenger RNA (mRNA) is crucial for gene expression in metazoans.
  • The Tap-p15 heterodimer is a key receptor mediating bulk mRNA export, interacting with adaptor proteins.
  • The role of specific adaptor proteins in regulating distinct mRNA export pathways remains incompletely understood.

Purpose of the Study:

  • To investigate the interaction of Thoc5, a subunit of the TREX complex, with the Tap-p15 export receptor.
  • To determine the role of Thoc5 in mRNA nuclear export, particularly in relation to bulk and specific mRNA populations.
  • To elucidate the functional cooperation between Thoc5, Aly, and Tap-p15 in mRNA export.

Main Methods:

  • Co-immunoprecipitation assays to study protein-protein interactions between Thoc5, Aly, and Tap-p15.
  • RNA-binding assays to assess the in vitro RNA-binding activity of Thoc5.
  • In vivo studies using mammalian cells to analyze the requirement of Thoc5 for bulk and specific mRNA export, including HSP70 mRNA.
  • Immunofluorescence and biochemical analyses to detect the association of Thoc5 with mRNA-protein complexes (mRNPs).

Main Results:

  • Thoc5 binds to a distinct surface on the Tap-p15 export receptor, separate from the Aly binding site.
  • Thoc5 is not essential for the nuclear export of bulk mRNA.
  • Nuclear export of HSP70 mRNA requires both Thoc5 and Aly, indicating a specific adaptor function.
  • Thoc5 demonstrates RNA-binding activity in vitro and is part of the stable THO complex associated with HSP70 mRNPs in vivo.

Conclusions:

  • Thoc5 functions as a specific export adaptor, cooperating with the Tap-p15 receptor for the export of certain mRNAs, such as HSP70 mRNA.
  • The combinatorial use of adaptors like Aly and co-adaptors like Thoc5 allows Tap-p15 to mediate the export of different mRNA classes.
  • This mechanism provides a flexible system for regulating specific mRNA nuclear export pathways.

More Related Videos

Studies of Chaperone-Cochaperone Interactions using Homogenous Bead-Based Assay06:51

Studies of Chaperone-Cochaperone Interactions using Homogenous Bead-Based Assay

Published on: July 21, 2021

Affinity Purification of Chloroplast Translocon Protein Complexes Using the TAP Tag07:01

Affinity Purification of Chloroplast Translocon Protein Complexes Using the TAP Tag

Published on: November 1, 2018

Related Concept Videos

Nuclear Export01:42

Nuclear Export

The nucleus restricts several proteins within and allows others to pass. The restricted proteins possess a nuclear retention sequence or NRS, anchoring them to the nuclear lamins and preventing their transport to the cytosol. The non-restricted proteins, after their synthesis, are transported to their site of action, such as the cytosol or other organelles, with the help of nuclear export signals or NES.
NES are of three types- the canonical 10-residue long leucine-rich signal and other...
Nuclear Export of mRNA02:31

Nuclear Export of mRNA

Before mRNAs are exported to the cytoplasm, it is crucial to check each mRNA for structural and functional integrity. Eukaryotic cells use several different mechanisms, collectively known as mRNA surveillance, to look for irregularities in mRNAs. Irregular or aberrant mRNA are rapidly degraded by various enzymes. If a defective mRNA escapes the surveillance, it would be translated into a protein which would either be non-functional or not function properly. One of the primary irregularities in...
Nuclear Export of mRNA02:31

Nuclear Export of mRNA

Before mRNAs are exported to the cytoplasm, it is crucial to check each mRNA for structural and functional integrity. Eukaryotic cells use several different mechanisms, collectively known as mRNA surveillance, to look for irregularities in mRNAs. Irregular or aberrant mRNA are rapidly degraded by various enzymes. If a defective mRNA escapes the surveillance, it would be translated into a protein which would either be non-functional or not function properly. One of the primary irregularities in...
Tail-anchoring of Proteins in the ER Membrane01:45

Tail-anchoring of Proteins in the ER Membrane

Tail-anchored, or TA, proteins are estimated to make up to 3-5% of membrane proteins found in the eukaryotic cell. Such proteins have a single transmembrane domain located approximately 30 amino acid residues upstream from the C-terminal end. As a result, the signal recognition particle (SRP) cannot guide a TA protein to the ER membrane for cotranslational insertion. Hence, they are integrated into the ER membrane post-translationally using their C-terminal end as the anchor. TA proteins...
Cotranslational Protein Translocation01:20

Cotranslational Protein Translocation

Translocation of proteins across membranes is an ancient process that occurs even in bacteria and archaebacteria. In fact, the components of the translocation machinery are still conserved between prokaryotes and eukaryotes.
Sec61 channel partners for cotranslational translocation
During cotranslational translocation, the Sec61 channel partners with the signal recognition particle (SRP), the signal recognition particle receptor (SR), and the ribosomes to transport the nascent polypeptide chain...
The ADP/ATP Carrier Protein01:42

The ADP/ATP Carrier Protein

ADP/ATP carrier or AAC protein is the most abundant carrier protein in the inner mitochondrial membrane. It transports large quantities of ADP and ATP, equivalent to the average human body weight, every day. Among other transporters, ACC protein is one of the best-studied members of the mitochondrial carrier protein family. The ADP/ATP carrier protein comprises two transmembrane helices connected to a loop and a single alpha-helix on the matrix side. It switches between two conformational...