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Examining BCL-2 Family Function with Large Unilamellar Vesicles
08:35

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Published on: October 5, 2012

The N-terminal helix of Bcl-xL targets mitochondria

Melanie A McNally1, Lucian Soane, Brian A Roelofs

  • 1W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University, Bloomberg School of Public Health, Baltimore, MD 21205, USA. mmcnall5@jhmi.edu

Mitochondrion
|January 22, 2013
PubMed

Insights

The N-terminus of Bcl-xL protein contains mitochondrial targeting information. This region, while necessary for mitochondrial import, is not sufficient for efficient targeting.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Bcl-2 family proteins regulate apoptosis.
  • Mitochondrial outer membrane targeting sequences are known.
  • Bcl-xL also localizes to the inner mitochondrial membrane.

Purpose of the Study:

  • Investigate N-terminus of Bcl-xL for mitochondrial targeting information.
  • Determine if N-terminal residues contribute to Bcl-xL's mitochondrial localization.

Main Methods:

  • Amino acid residues 1-28 of Bcl-xL were fused to EGFP.
  • Mitochondrial targeting of the fusion protein was assessed.
  • Analysis of charge and helical propensity requirements.

Main Results:

  • Bcl-xL residues 1-28 fused to EGFP were sufficient for mitochondrial targeting.
  • Positive charges and helical propensity are required for this targeting.
  • The N-terminus alone was insufficient for efficient mitochondrial import.

Conclusions:

  • The N-terminus of Bcl-xL contains mitochondrial targeting information.
  • This region plays a role in Bcl-xL's localization to mitochondria.
  • Further investigation is needed to understand the full mechanism of inner mitochondrial membrane targeting.

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