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Intracellular calcium levels can regulate Importin-dependent nuclear import

Gurpreet Kaur1, Jennifer D Ly-Huynh1, David A Jans1

  • 1Nuclear Signalling Laboratory, Dept. of Biochemistry and Molecular Biology, Monash University, Australia.

Biochemical and Biophysical Research Communications
|June 24, 2014
PubMed

Insights

High intracellular calcium levels disrupt nuclear import by affecting key transport proteins like Importin beta1 (Impβ1) and Ran. This finding reveals a direct mechanism by which calcium influences cellular transport processes.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Increased intracellular calcium is known to modulate specific nuclear import pathways, such as for SRY-related chromatin remodeling proteins.
  • The precise mechanisms by which calcium influences general nuclear protein import remain incompletely understood.

Purpose of the Study:

  • To investigate the general effect of high intracellular calcium on Importin alpha/beta1 (Impα/β1) and Importin beta1 (Impβ1)-dependent nuclear import.
  • To elucidate the underlying molecular mechanisms of calcium-mediated modulation of nuclear transport.

Main Methods:

  • Utilized cell-based assays to monitor nuclear protein import under conditions of elevated intracellular calcium.
  • Investigated the subnuclear localization of key transport factors, including Importin beta1 (Impβ1), Ran, and RCC1, using microscopy and biochemical fractionation.

Main Results:

  • High intracellular calcium significantly inhibits general Impα/β1- and Impβ1-dependent nuclear protein import.
  • Elevated calcium levels lead to increased nuclear localization of Impβ1 and Ran.
  • Altered subnuclear localization of RCC1 was observed in response to high intracellular calcium.

Conclusions:

  • Intracellular calcium directly impacts the nuclear transport machinery, affecting the localization of essential transport factors.
  • This study establishes a novel mechanism by which calcium ions regulate conventional nuclear import pathways.
  • The findings provide new insights into calcium signaling and its role in nuclear transport regulation.
Keywords:
CalciumImportinsNuclear importNucleocytoplasmic transportRan GTPase

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