Polymerase transcriptase release factor (PTRF) anchors MG53 protein to cell injury site for initiation of membrane repair

J Biol Chem. 2011 Apr 15;286(15):12820-4. doi: 10.1074/jbc.C111.221440. Epub 2011 Feb 22.

Abstract

Plasma membrane repair is an essential process for maintenance of homeostasis at the cellular and tissue levels, whereas compromised repair capacity contributes to degenerative human diseases. Our recent studies show that MG53 is essential for muscle membrane repair, and defects in MG53 function are linked to muscular dystrophy and cardiac dysfunction. Here we report that polymerase I and transcript release factor (PTRF), a gene known to regulate caveolae membrane structure, is an indispensable component of the membrane repair machinery. PTRF acts as a docking protein for MG53 during membrane repair potentially by binding exposed membrane cholesterol at the injury site. Cells lacking expression of endogenous PTRF show defective trafficking of MG53 to membrane injury sites. A mutation in PTRF associated with human disease results in aberrant nuclear localization of PTRF and disrupts MG53 function in membrane resealing. Although RNAi silencing of PTRF leads to defective muscle membrane repair, overexpression of PTRF can rescue membrane repair defects in dystrophic muscle. Our data suggest that membrane-delimited interaction between MG53 and PTRF contributes to initiation of cell membrane repair, which can be an attractive target for treatment or prevention of tissue injury in human diseases.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Caveolae / metabolism*
  • Caveolae / pathology
  • Cell Nucleus / genetics
  • Cell Nucleus / metabolism
  • Cell Nucleus / pathology
  • HeLa Cells
  • Heart Diseases / genetics
  • Heart Diseases / metabolism
  • Heart Diseases / pathology
  • Hep G2 Cells
  • Humans
  • Membrane Proteins
  • Mice
  • Muscle, Skeletal / metabolism*
  • Muscle, Skeletal / pathology
  • Muscular Dystrophies / genetics
  • Muscular Dystrophies / metabolism
  • Muscular Dystrophies / pathology
  • Muscular Dystrophies / therapy
  • Mutation
  • Protein Transport / genetics
  • RNA-Binding Proteins / genetics
  • RNA-Binding Proteins / metabolism*
  • Tripartite Motif Proteins

Substances

  • CAVIN1 protein, human
  • Carrier Proteins
  • Cavin1 protein, mouse
  • MG53 protein, mouse
  • Membrane Proteins
  • RNA-Binding Proteins
  • TRIM72 protein, human
  • Tripartite Motif Proteins