Self-interaction of Human Pex11pβ During Peroxisomal Growth and Division

PLoS One. 2013;8(1):e53424. doi: 10.1371/journal.pone.0053424. Epub 2013 Jan 7.

Abstract

Pex11 proteins are involved in membrane elongation and division processes associated with the multiplication of peroxisomes. Human Pex11pβ has recently been linked to a new disorder affecting peroxisome morphology and dynamics. Here, we have analyzed the exact membrane topology of Pex11pβ. Studies with an epitope-specific antibody and protease protection assays show that Pex11pβ is an integral membrane protein with two transmembrane domains flanking an internal region exposed to the peroxisomal matrix and N- and C-termini facing the cytosol. A glycine-rich internal region within Pex11pβ is dispensable for peroxisome membrane elongation and division. However, we demonstrate that an amphipathic helix (Helix 2) within the first N-terminal 40 amino acids is crucial for membrane elongation and self-interaction of Pex11pβ. Interestingly, we find that Pex11pβ self-interaction strongly depends on the detergent used for solubilization. We also show that N-terminal cysteines are not essential for membrane elongation, and that putative N-terminal phosphorylation sites are dispensable for Pex11pβ function. We propose that self-interaction of Pex11pβ regulates its membrane deforming activity in conjunction with membrane lipids.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • COS Cells
  • Chlorocebus aethiops
  • Humans
  • Intracellular Membranes / chemistry
  • Intracellular Membranes / metabolism*
  • Membrane Proteins / chemistry*
  • Membrane Proteins / metabolism
  • Peroxisomes / chemistry
  • Peroxisomes / metabolism*
  • Phosphorylation
  • Protein Interaction Domains and Motifs
  • Protein Structure, Secondary
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / metabolism
  • Transfection

Substances

  • Membrane Proteins
  • PEX11B protein, human
  • Recombinant Fusion Proteins

Grant support

This work was supported by the Portuguese Foundation for Science and Technology (FCT) and FEDER (PTDC/BIA-BCM/099613/2008 to M.S., SFRH/BD/37647/2007 to N.A.B., SFRH/BD/45427/2008 to M.J.C., SFRH/BD/80542/2011 to M. Almeida, SFRH/BD/48722/2008 to M. Aroso, SFRH/BD/81223/2011 to A.G., SFRH/BPD/77619/2011 to D.R., SFRH/BPD/74428/2010 to M.I.) and CRUP/DAAD (ACÇÕES INTEGRADAS 2010, A-29/11. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.