Dictyostelium myosin bipolar thick filament formation: Importance of charge and specific domains of the myosin rod

Daniel Hostetter, Sarah Rice, Sara Dean, David Altman, Peggy M. McMahon, Shirley Sutton, Ashutosh Tripathy, James A. Spudich*

*Corresponding author for this work

Research output: Contribution to journalArticle

22 Scopus citations

Abstract

Myosin-II thick filament formation in Dictyostelium is an excellent system for investigating the phenomenon of self-assembly, as the myosin molecule itself contains all the information required to form a structure of defined size. Phosphorylation of only three threonine residues can dramatically change the assembly state of myosin-II. We show here that the C-terminal 68 kDa of the myosin-II tail (termed AD-Cterm) assembles in a regulated manner similar to full-length myosin-II and forms bipolar thick filament (BTF) structures when a green fluorescent protein (GFP) "head" is added to the N terminus. The localization of this GFP-AD-Cterm to the cleavage furrow of dividing Dictyostelium cells depends on assembly state, similar to full-length myosin-II. This tail fragment therefore represents a good model system for the regulated formation and localization of BTFs. By reducing regulated BTF assembly to a more manageable model system, we were able to explore determinants of myosin-II self-assembly. Our data support a model in which a globular head limits the size of a BTF, and the large-scale charge character of the AD-Cterm region is important for BTF formation. Truncation analysis of AD-Cterm tail fragments shows that assembly is delicately balanced, resulting in assembled myosin-II molecules that are poised to disassemble due to the phosphorylation of only three threonines. Copyright:

Original languageEnglish (US)
JournalPLoS biology
Volume2
Issue number11
DOIs
StatePublished - Nov 2004

ASJC Scopus subject areas

  • Neuroscience(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)
  • Agricultural and Biological Sciences(all)

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    Hostetter, D., Rice, S., Dean, S., Altman, D., McMahon, P. M., Sutton, S., Tripathy, A., & Spudich, J. A. (2004). Dictyostelium myosin bipolar thick filament formation: Importance of charge and specific domains of the myosin rod. PLoS biology, 2(11). https://doi.org/10.1371/journal.pbio.0020356