Myosin IIB is unconventionally conventional

Steven S. Rosenfeld, Jun Xing, Li Qiong Chen, H. Lee Sweeney

Research output: Contribution to journalArticlepeer-review

88 Scopus citations


Members of the myosin II class of molecular motors have been referred to as "conventional," a term used to describe their ability to form thick filaments, their low duty ratio, the ability of individual motor-containing "heads" to operate independently of each other, and their rate-limiting phosphate release. These features ensure that those motors that have completed their power stroke dissociate rapidly enough to prevent them from interfering with those motors that are beginning theirs. However, in this study, we demonstrate that myosin IIB, a cytoplasmic myosin II particularly enriched in the central nervous system and cardiac tissue, has a number of features that it shares instead with "unconventional" myosin isoforms, including myosins V and VI. These include a high duty ratio, rate-limiting ADP release, and high ADP affinity. These features imply that myosin IIB serves a set of physiologic needs different from those served by its more conventional myosin II counterparts, and this work provides a plausible basis for explaining the physiologic role of this unconventionally conventional myosin.

Original languageEnglish (US)
Pages (from-to)27449-27455
Number of pages7
JournalJournal of Biological Chemistry
Issue number30
StatePublished - Jul 25 2003

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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