TY - JOUR
T1 - Differential localization of unconventional myosin I and nonmuscle myosin II during B cell spreading
AU - Sumoza-Toledo, Adriana
AU - Gillespie, Peter G.
AU - Romero-Ramirez, Hector
AU - Ferreira-Ishikawa, Hellen C.
AU - Larson, Roy E.
AU - Santos-Argumedo, Leopoldo
N1 - Funding Information:
We thank QBP. Blanca Esthela Reyes and QBP. Juana Narvaez Morales for the confocal microscopy and MVZ Ricardo Gaxiola-Centeno for the animal care facilities. We also thank Dr. Fernando Navarro for allowing us the use of the confocal microscope at the beginning of this study, and Dr. Ricardo Mondragón and Dra. Isaura Meza for their suggestions. This work was supported by grants from Consejo Nacional de Ciencia y Tecnología (CONACYT), México (28093N, 33497N and 40218Q).
PY - 2006/10/15
Y1 - 2006/10/15
N2 - 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.
AB - 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.
KW - B cell
KW - CD44
KW - Cytoskeleton
KW - F-actin
KW - Myosin
KW - Spreading
UR - http://www.scopus.com/inward/record.url?scp=33748756985&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33748756985&partnerID=8YFLogxK
U2 - 10.1016/j.yexcr.2006.07.002
DO - 10.1016/j.yexcr.2006.07.002
M3 - Article
C2 - 16919270
AN - SCOPUS:33748756985
SN - 0014-4827
VL - 312
SP - 3312
EP - 3322
JO - Experimental Cell Research
JF - Experimental Cell Research
IS - 17
ER -