A regulatory motif in nonmuscle myosin II-B regulates its role in migratory front-back polarity

J Cell Biol. 2015 Apr 13;209(1):23-32. doi: 10.1083/jcb.201407059.


In this study, we show that the role of nonmuscle myosin II (NMII)-B in front-back migratory cell polarity is controlled by a short stretch of amino acids containing five serines (1935-1941). This motif resides near the junction between the C terminus helical and nonhelical tail domains. Removal of this motif inhibited NMII-B assembly, whereas its insertion into NMII-A endowed an NMII-B-like ability to generate large actomyosin bundles that determine the rear of the cell. Phosphomimetic mutation of the five serines also inhibited NMII-B assembly, rendering it unable to support front-back polarization. Mass spectrometric analysis showed that several of these serines are phosphorylated in live cells. Single-site mutagenesis showed that serine 1935 is a major regulatory site of NMII-B function. These data reveal a novel regulatory mechanism of NMII in polarized migrating cells by identifying a key molecular determinant that confers NMII isoform functional specificity.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actomyosin / metabolism
  • Amino Acid Sequence
  • Animals
  • CHO Cells
  • Cell Adhesion
  • Cell Movement
  • Cell Polarity*
  • Cricetinae
  • Cricetulus
  • HEK293 Cells
  • Humans
  • Molecular Sequence Data
  • Myosin Heavy Chains / chemistry
  • Myosin Heavy Chains / physiology*
  • Nonmuscle Myosin Type IIB / chemistry
  • Nonmuscle Myosin Type IIB / physiology*
  • Protein Stability
  • Protein Structure, Tertiary


  • Actomyosin
  • Nonmuscle Myosin Type IIB
  • nonmuscle myosin type IIB heavy chain
  • Myosin Heavy Chains