GTP-binding-defective ARL4D alters mitochondrial morphology and membrane potential

PLoS One. 2012;7(8):e43552. doi: 10.1371/journal.pone.0043552. Epub 2012 Aug 21.

Abstract

ARL4D, ARL4A, and ARL4C are closely related members of the ADP-ribosylation factor/ARF-like protein (ARF/ARL) family of GTPases. All three ARL4 proteins contain nuclear localization signals (NLSs) at their C-termini and are primarily found at the plasma membrane, but they are also present in the nucleus and cytoplasm. ARF function and localization depends on their controlled binding and hydrolysis of GTP. Here we show that GTP-binding-defective ARL4D is targeted to the mitochondria, where it affects mitochondrial morphology and function. We found that a portion of endogenous ARL4D and the GTP-binding-defective ARL4D mutant ARL4D(T35N) reside in the mitochondria. The N-terminal myristoylation of ARL4D(T35N) was required for its localization to mitochondria. The localization of ARL4D(T35N) to the mitochondria reduced the mitochondrial membrane potential (ΔΨm) and caused mitochondrial fragmentation. Furthermore, the C-terminal NLS region of ARL4D(T35N) was required for its effect on the mitochondria. This study is the first to demonstrate that the dysfunctional GTP-binding-defective ARL4D is targeted to mitochondria, where it subsequently alters mitochondrial morphology and membrane potential.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ADP-Ribosylation Factors / chemistry
  • ADP-Ribosylation Factors / genetics
  • ADP-Ribosylation Factors / metabolism*
  • Animals
  • Apoptosis
  • COS Cells
  • Cell Proliferation
  • Cell Survival
  • Chlorocebus aethiops
  • Guanosine Triphosphate / metabolism*
  • HeLa Cells
  • Humans
  • Membrane Potential, Mitochondrial*
  • Mitochondria / metabolism*
  • Mutation
  • Nuclear Localization Signals
  • Protein Processing, Post-Translational
  • Protein Transport

Substances

  • Nuclear Localization Signals
  • Guanosine Triphosphate
  • ADP-Ribosylation Factors
  • Arl4D protein, mouse

Grant support

This work was supported by grants from the National Science Council, Taiwan (NSC 97-3112-B-002-016, NSC-100 2325-B-022-028), National Taiwan University Hospital (99P21-1), and the Yung-Shin Biomedical Research Fund (YSP-86-019) to F.-J.S. Lee. The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.