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Single-Molecule Imaging of Nuclear Transport
12:13

Single-Molecule Imaging of Nuclear Transport

Published on: June 10, 2010

Translocation of nucleophosmin from nucleoli to nucleoplasm requires ATP

M H Wu1, C Y Lam, B Y Yung

  • 1Graduate Institute of Pharmacology, Yang Ming Medical College, Taiwan, Republic of China.

The Biochemical Journal
|February 1, 1995
PubMed

Insights

Adenosine triphosphate (ATP) is essential for nucleophosmin (NPM) movement from the nucleolus to the nucleoplasm in HeLa cells. This ATP-dependent translocation was demonstrated using an in vitro permeabilized cell system.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Nucleophosmin (NPM) is a multifunctional protein involved in various cellular processes.
  • NPM shuttles between the nucleolus and cytoplasm, a process implicated in cellular stress responses.
  • Cytotoxic drugs can induce NPM translocation, but the underlying biochemical mechanisms remain unclear.

Purpose of the Study:

  • To investigate the biochemical requirements for nucleophosmin translocation from the nucleolus to the nucleoplasm.
  • To establish and utilize an in vitro system for studying nucleophosmin redistribution.

Main Methods:

  • HeLa cells were treated with cytotoxic drugs and antimycin A in glucose-free medium to deplete ATP.
  • An in vitro system using Triton-permeabilized HeLa cells was developed.
  • Nucleophosmin translocation was assessed using immunofluorescence, ELISA, and Western blotting.
  • ATP's role was evaluated by adding exogenous ATP to permeabilized cells.

Main Results:

  • Cytotoxic drug-induced nucleophosmin translocation was inhibited by ATP depletion.
  • An in vitro system with permeabilized HeLa cells demonstrated ATP-dependent nucleophosmin translocation.
  • Nucleophosmin levels and its oligomeric state remained unchanged during ATP-induced translocation.
  • The permeabilized cell model showed efficient translocation with exogenous factors.

Conclusions:

  • Adenosine triphosphate (ATP) is a critical requirement for nucleophosmin translocation from the nucleolus to the nucleoplasm.
  • The developed in vitro permeabilized cell system provides a robust platform for dissecting the biochemical details of nucleophosmin nucleocytoplasmic transport.

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