Distinct amino acid motifs carrying multiple positive charges regulate membrane targeting of dysferlin and MG53

PLoS One. 2018 Aug 9;13(8):e0202052. doi: 10.1371/journal.pone.0202052. eCollection 2018.

Abstract

Dysferlin (Dysf) and mitsugumin53 (MG53) are two key proteins involved in membrane repair of muscle cells which are efficiently recruited to the sarcolemma upon lesioning. Plasma membrane localization and recruitment of a Dysf fragment to membrane lesions in zebrafish myofibers relies on the presence of a short, polybasic amino acid motif, WRRFK. Here we show that the positive charges carried by this motif are responsible for this function. In mouse MG53, we have identified a similar motif with multiple basic residues, WKKMFR. A single amino acid replacement, K279A, leads to severe aggregation of MG53 in inclusion bodies in HeLa cells. This result is due to the loss of positive charge, as shown by studying the effects of other neutral amino acids at position 279. Consequently, our data suggest that positively charged amino acid stretches play an essential role in the localization and function of Dysf and MG53.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs*
  • Amino Acids / chemistry*
  • Animals
  • Carrier Proteins / chemistry*
  • Cell Membrane / metabolism
  • Dysferlin / chemistry*
  • HeLa Cells
  • Humans
  • Mice
  • Microscopy, Confocal
  • Muscle Proteins / metabolism
  • Muscle, Skeletal / metabolism
  • Mutation
  • Protein Binding
  • Protein Domains
  • Sarcolemma / metabolism
  • Tripartite Motif Proteins
  • Tryptophan / chemistry
  • Zebrafish

Substances

  • Amino Acids
  • Carrier Proteins
  • DYSF protein, human
  • Dysferlin
  • Muscle Proteins
  • TRIM72 protein, human
  • Tripartite Motif Proteins
  • Tryptophan

Grants and funding

US and GUN were funded by the Helmholtz-Gemeinschaft (HGF, grants STN and BITFTM) and Deutsche Forschungsgemeinschaft (DFG, grants STR 439/8-1, Ni 291/12-1 and GRK 2039). We also acknowledge financial support by the DFG and Open Access Publishing Fund of KIT for publication charges. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.