Localization of wild type and mutant class I myosin proteins in Aspergillus nidulans using GFP-fusion proteins

Cell Motil Cytoskeleton. 2000 Feb;45(2):163-72. doi: 10.1002/(SICI)1097-0169(200002)45:2<163::AID-CM7>3.0.CO;2-D.


We have examined the distribution of MYOA, the class I myosin protein of the filamentous fungus Aspergillus nidulans, as a GFP fusion protein. Wild type GFP-MYOA expressed from the myoA promoter is able to rescue a conditional myoA null mutant. Growth of a strain expressing GFP-MYOA as the only class I myosin was approximately 50% that of a control strain, demonstrating that the fusion protein retains substantial myosin function. The distribution of the wild type GFP-MYOA fusion is enriched in growing hyphal tips and at sites of septum formation. In addition, we find that GFP-MYOA is also found in patches at the cell cortex. We have also investigated the effects of deletion or truncation mutations in the tail domain on MYOA localization. Mutant GFP-MYOA fusions that lacked either the C-terminal SH3 or a portion of the C-terminal proline-rich domain had subcellular distributions like wild type MYOA, consistent with their ability to complement a myoA null mutant. In contrast, mutants lacking all of the C-terminal proline-rich domain or the TH-1-like domain were mainly localized diffusely throughout the cytoplasm, but could less frequently be found in patches, and were unable to complement a myoA null mutant. The GFP-MYOA DeltaIQ mutant was localized into large bright fluorescent patches in the cytoplasm. This mutant protein was subsequently found to be insoluble.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aspergillus nidulans / cytology
  • Aspergillus nidulans / metabolism*
  • Blotting, Southern
  • Fungal Proteins / chemistry
  • Fungal Proteins / genetics
  • Fungal Proteins / metabolism*
  • Green Fluorescent Proteins
  • Luminescent Proteins / genetics
  • Luminescent Proteins / metabolism
  • Mutation
  • Myosin Type I*
  • Myosins / chemistry
  • Myosins / genetics
  • Myosins / metabolism*
  • Protein Conformation
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Solubility
  • Spores, Fungal / cytology
  • Spores, Fungal / physiology


  • Fungal Proteins
  • Luminescent Proteins
  • MyoA protein, Aspergillus nidulans
  • Recombinant Fusion Proteins
  • Green Fluorescent Proteins
  • Myosin Type I
  • Myosins