Related Experiment Video

Updated: Aug 13, 2026

Heterokaryon Technique for Analysis of Cell Type-specific Localization
09:31

Heterokaryon Technique for Analysis of Cell Type-specific Localization

Published on: March 11, 2011

Nuclear-cytoplasmic shuttling of Axin regulates subcellular localization of beta-catenin

Feng Cong1, Harold Varmus

  • 1Cancer Biology and Genetics Program, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA. congf@mskcc.org

Proceedings of the National Academy of Sciences of the United States of America
|February 26, 2004
PubMed

Insights

Axin protein shuttles between the nucleus and cytoplasm, regulating beta-catenin distribution. This molecular chaperone function is crucial for Wnt signaling pathway control.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Developmental Biology

Background:

  • Wnt signaling is vital for development, primarily through beta-catenin.
  • Axin acts as a negative regulator, forming the beta-catenin degradation complex.
  • Previous studies suggested Axin influences beta-catenin localization independently of degradation.

Purpose of the Study:

  • To investigate the subcellular localization and shuttling of Axin.
  • To determine the role of Axin's nuclear-cytoplasmic transport in regulating beta-catenin.
  • To elucidate Axin's function as a molecular chaperone for beta-catenin.

Main Methods:

  • Studied Axin's nuclear-cytoplasmic shuttling using leptomycin B, a chromosome maintenance region 1 inhibitor.
  • Mapped functional nuclear localization and export signals within Axin.
  • Assessed the impact of Axin fragments on beta-catenin localization in coexpression studies.

Main Results:

  • Axin was identified as a nuclear-cytoplasmic shuttling protein.
  • Nuclear export of Axin is mediated by the chromosome maintenance region 1 receptor.
  • Overexpression of an Axin fragment induced cytoplasmic localization of beta-catenin, dependent on Axin shuttling.

Conclusions:

  • Axin functions as a molecular chaperone for beta-catenin.
  • The nuclear-cytoplasmic shuttling of Axin is a key mechanism regulating beta-catenin distribution.
  • This shuttling activity plays a significant role in modulating Wnt signaling pathways.

More Related Videos

Isolation of CA1 Nuclear Enriched Fractions from Hippocampal Slices to Study Activity-dependent Nuclear Import of Synapto-nuclear Messenger Proteins10:03

Isolation of CA1 Nuclear Enriched Fractions from Hippocampal Slices to Study Activity-dependent Nuclear Import of Synapto-nuclear Messenger Proteins

Published on: August 10, 2014

Reconstitution Of β-catenin Degradation In Xenopus Egg Extract09:41

Reconstitution Of β-catenin Degradation In Xenopus Egg Extract

Published on: June 17, 2014

Related Concept Videos

Nuclear Protein Sorting01:34

Nuclear Protein Sorting

Nuclear protein sorting is the selective trafficking of histones, polymerases, gene regulatory proteins into the nucleus and exporting RNAs and ribosomes to the cytosol. It is a tightly controlled process that regulates gene expression within a cell.
Proteins targeted to the nucleus carry nuclear localization signals or NLS recognized by import receptors in the cytosol. Similarly, proteins with nuclear export signals are recognized by export receptors. Import and export receptors are...
Nuclear Localization Signals and Import01:46

Nuclear Localization Signals and Import

Proteins targeted to the nucleus carry short stretches of amino acid sequences called the nuclear localization signal or NLS. Classical nuclear localization signals are of two types: monopartite and bipartite NLS. Monopartite classical NLS (cNLS) consists of a single cluster of 4-8 amino acids. Bipartite cNLS consists of two clusters of  2-3 amino acids and a 9-12 residue long proline-rich linker bridging the two clusters. Signal clusters are rich in positively charged amino acids such as...
Directionality of Nuclear Transport01:42

Directionality of Nuclear Transport

Ras-related nuclear protein or Ran is a small G protein that cycles between its GTP and GDP bound states. Ran specific regulators, a Ran GTPase Activating Protein or RanGAP present in the cytosol and a Ran guanine nucleotide exchange factor or RanGEF present inside the nucleus regulate GTP/GDP exchange. A high concentration of GTP inside the cells, in addition to this asymmetric distribution of  Ran-specific regulators, leads to a higher RanGTP concentration inside the nucleus. This...
Regulation of Nuclear Protein Sorting01:45

Regulation of Nuclear Protein Sorting

Nuclear protein sorting regulates nucleus composition and gene expression, crucial for determining the fate of a eukaryotic cell. Hence, the entry and exit of molecules across the nuclear envelope is a tightly controlled process. Nuclear protein sorting can be inhibited by one of the following ways: 1) masking cargo signal sequences, 2) modifying the nuclear receptor's affinity for cargo, 3) controlling the nuclear pore size, 4) retaining the cargo during its transit to the cytosol or the...
Cytoskeletal Coordination in Cell Migration01:32

Cytoskeletal Coordination in Cell Migration

A migrating cell changes its shape during the cyclic events of attachment and detachment from the substratum and repositions the cell organelles correspondingly. These complex events are orchestrated by the dynamic cytoskeletal network comprising actin filaments, intermediate filaments, and microtubules. Cytoskeletal crosstalk — the direct and indirect communication between the different components — is crucial for this coordination. Direct communication involves various linker proteins that...
Catenins01:23

Catenins

Catenins are characterized by multiple binding domains and dynamic structures that allow them to function as linker proteins in cell junction complexes. All catenins, except α-catenin, contain a characteristic protein sequence called the armadillo repeat and are therefore also called armadillo proteins.
Catenins in Cell Junctions
Catenins bind to cell adhesion molecules such as cadherins and link them to different cytoskeletal proteins depending on the type of cell junction. At the adherens...