Tail chimeras of Dictyostelium myosin II support cytokinesis and other myosin II activities but not full development

Shi Shu, Xiong Liu, Carole A. Parent, Taro Q.P. Uyeda, Edward D. korn

Research output: Contribution to journalReview article

10 Citations (Scopus)

Abstract

Dictyostelium lacking myosin II cannot grow in suspension culture, develop beyond the mound stage or cap concanavalin A receptors and chemotaxis is impaired. Recently, we showed that the actin-activated MgATPase activity of myosin chimeras in which the tail domain of Dictyostelium myosin II heavy chain is replaced by the tail domain of either Acanthamoeba or chicken smooth muscle myosin II is unregulated and about 20 times higher than wild-type myosin. The Acanthamoeba chimera forms short bipolar filaments similar to, but shorter than, filaments of Dictyostelium myosin and the smooth muscle chimera forms much larger side-polar filaments. We now find that the Acanthamoeba chimera expressed in myosin null cells localizes to the periphery of vegetative amoeba similarly to wild-type myosin but the smooth muscle chimera is heavily concentrated in a single cortical patch. Despite their different tail sequences and filament structures and different localization of the smooth muscle chimera in interphase cells, both chimeras support growth in suspension culture and concanavalin A capping and colocalize with the ConA cap but the Acanthamoeba chimera subsequently disperses more slowly than wild-type myosin and the smooth muscle chimera apparently not at all. Both chimeras also partially rescue chemotaxis. However, neither supports full development. Thus, neither regulation of myosin activity, nor regulation of myosin polymerization nor bipolar filaments is required for many functions of Dictyostelium myosin II and there may be no specific sequence required for localization of myosin to the cleavage furrow.

Original languageEnglish
Pages (from-to)4237-4249
Number of pages13
JournalJournal of Cell Science
Volume115
Issue number22
DOIs
Publication statusPublished - 2002 Nov 15
Externally publishedYes

Keywords

  • Chemotaxis
  • ConA capping
  • Cytokinesis
  • Developement
  • MyosinII

ASJC Scopus subject areas

  • Cell Biology

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