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Spatio-Temporal Manipulation of Small GTPase Activity at Subcellular Level and on Timescale of Seconds in Living Cells
10:27

Spatio-Temporal Manipulation of Small GTPase Activity at Subcellular Level and on Timescale of Seconds in Living Cells

Published on: March 9, 2012

Small Jab1-containing subcomplex is regulated in an anchorage- and cell cycle-dependent manner, which is abrogated by

Akihisa Fukumoto1, Kiichiro Tomoda, Makoto Kubota

  • 1First Department of Surgery, Nara Medical University, Nara, Japan.

FEBS Letters
|February 16, 2005
PubMed

Insights

Jab1 (Jun activation domain-binding protein 1) forms distinct complexes that regulate cell growth. A small Jab1 complex, dependent on cell density and anchorage, may mediate crucial signaling pathways.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Signal Transduction

Background:

  • Jab1 (Jun activation domain-binding protein 1) is a key regulator of cell proliferation, differentiation, and tumorigenesis.
  • It interacts with various cell cycle and signal transduction proteins.

Purpose of the Study:

  • To investigate the distinct Jab1-containing protein complexes.
  • To characterize the formation and regulation of a novel small Jab1-containing subcomplex.

Main Methods:

  • Non-denaturing gel electrophoresis was used to separate Jab1 complexes.
  • Cell density, anchorage, and cell cycle phase were manipulated to study complex formation.

Main Results:

  • Two distinct Jab1 complexes were identified: the COP9 signalosome complex and a small Jab1-containing subcomplex.
  • Small Jab1 complex formation was dependent on low cell density and anchorage.
  • This complex formation was enhanced in early G1 phase but abrogated in ras-transformed cells.

Conclusions:

  • A novel small Jab1-containing subcomplex was identified.
  • This subcomplex may act as a mediator for anchorage and cell-cell contact-dependent signal transduction pathways.
  • Its formation is regulated by cellular microenvironment and cell cycle progression.

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