Premium
The role of actin and myosin in PtK2 spindle length changes induced by laser microbeam irradiations across the spindle
Author(s) -
Sheykhani Rozhan,
Baker Norman,
GomezGodinez Veronica,
Liaw LihHuei,
Shah Jagesh,
Berns Michael W.,
Forer Arthur
Publication year - 2013
Publication title -
cytoskeleton
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.95
H-Index - 86
eISSN - 1949-3592
pISSN - 1949-3584
DOI - 10.1002/cm.21104
Subject(s) - myosin , spindle pole body , biology , spindle apparatus , microtubule , actin , microbiology and biotechnology , microbeam , astral microtubules , cytoskeleton , anatomy , microfilament , biophysics , cell division , optics , biochemistry , physics , cell
This study investigates spindle biomechanical properties to better understand how spindles function. In this report, laser microbeam cutting across mitotic spindles resulted in movement of spindle poles toward the spindle equator. The pole on the cut side moved first, the other pole moved later, resulting in a shorter but symmetric spindle. Intervening spindle microtubules bent and buckled during the equatorial movement of the poles. Because of this and because there were no detectable microtubules within the ablation zone, other cytoskeletal elements would seem to be involved in the equatorial movement of the poles. One possibility is actin and myosin since pharmacological poisoning of the actin–myosin system altered the equatorial movements of both irradiated and unirradiated poles. Immunofluorescence microscopy confirmed that actin, myosin and monophosphorylated myosin are associated with spindle fibers and showed that some actin and monophosphorylated myosin remained in the irradiated regions. Overall, our experiments suggest that actin, myosin and microtubules interact to control spindle length. We suggest that actin and myosin, possibly in conjunction with the spindle matrix, cause the irradiated pole to move toward the equator and that cross‐talk between the two half spindles causes the unirradiated pole to move toward the equator until a balanced length is obtained. © 2013 Wiley Periodicals, Inc