Differential localization of unconventional myosin I and nonmuscle myosin II during B cell spreading

Adriana Sumoza-Toledo, Peter Barr-Gillespie, Hector Romero-Ramirez, Hellen C. Ferreira-Ishikawa, Roy E. Larson, Leopoldo Santos-Argumedo

Research output: Contribution to journalArticle

7 Scopus citations


Cross-linking of CD44 in vitro promotes chemokinesis and actin-based dendrite formation in T and B cells. However, the mechanisms by which the adhesion molecule CD44 induces cytoskeleton activation in lymphocytes are still poorly understood. In this study, we have investigated whether myosin isoforms are involved in CD44-dependent dendrite formation in activated B cells. Pharmacological inhibition of myosin with 2,3-butanedione monoxime strongly affected spreading and dendrite formation, suggesting that these cellular motors may participate in these phenomena. Furthermore, immunofluorescence analysis showed differences in subcellular localization of class I and class II myosin during B cell spreading. In response to CD44 cross-linking, myosin-1c was polarized to lamellipodia, where F-actin was high. In contrast, the distribution of cytosplasmic nonmuscle class II myosin was not altered. Expressions of myosin-1c and II were also demonstrated in B cells by Western blot. Although the inhibition of PLCγ, PI3K and MEK-1 activation affected the spreading and dendrite formation in activated B cells, only PLCγ and MEK-1 inhibition correlated with absence of myosin-1c polarization. Additionally, myosin-1c polarization was observed upon cross-linking of other surface molecules, suggesting a common mechanism for B cell spreading. This work shows that class I and class II myosin are expressed in B cells, are differentially distributed, and may participate in the morphological changes of these cells.

Original languageEnglish (US)
Pages (from-to)3312-3322
Number of pages11
JournalExperimental Cell Research
Issue number17
Publication statusPublished - Oct 15 2006



  • B cell
  • CD44
  • Cytoskeleton
  • F-actin
  • Myosin
  • Spreading

ASJC Scopus subject areas

  • Cell Biology

Cite this

Sumoza-Toledo, A., Barr-Gillespie, P., Romero-Ramirez, H., Ferreira-Ishikawa, H. C., Larson, R. E., & Santos-Argumedo, L. (2006). Differential localization of unconventional myosin I and nonmuscle myosin II during B cell spreading. Experimental Cell Research, 312(17), 3312-3322. https://doi.org/10.1016/j.yexcr.2006.07.002