TY - JOUR
T1 - Dynein Antagonizes Eg5 by Crosslinking and Sliding Antiparallel Microtubules
AU - Ferenz, Nick P.
AU - Paul, Raja
AU - Fagerstrom, Carey
AU - Mogilner, Alex
AU - Wadsworth, Patricia
N1 - Funding Information:
p150-CC1 plasmid was a kind gift of T. Kapoor (The Rockefeller University). Antibodies to Mad2 were a kind gift of A. Khodjakov (Wadsworth Center). We thank members of the Lee and Ross laboratories (University of Massachusetts Amherst) for insightful comments. This work was supported by grants from the National Institutes of Health (to A.M. and P.W.).
PY - 2009/11/17
Y1 - 2009/11/17
N2 - Mitotic spindle assembly requires the combined activity of various molecular motor proteins, including Eg5 [1] and dynein [2]. Together, these motors generate antagonistic forces during mammalian bipolar spindle assembly [3]; what remains unknown, however, is how these motors are functionally coordinated such that antagonism is possible. Given that Eg5 generates an outward force by crosslinking and sliding apart antiparallel microtubules (MTs) [4-6], we explored the possibility that dynein generates an inward force by likewise sliding antiparallel MTs. We reasoned that antiparallel overlap, and therefore the magnitude of a dynein-mediated force, would be inversely proportional to the initial distance between centrosomes. To capitalize on this relationship, we utilized a nocodazole washout assay to mimic spindle assembly. We found that Eg5 inhibition led to either monopolar or bipolar spindle formation, depending on whether centrosomes were initially separated by less than or greater than 5.5 μm, respectively. Mathematical modeling predicted this same spindle bistability in the absence of functional Eg5 and required dynein acting on antiparallel MTs to do so. Our results suggest that dynein functionally coordinates with Eg5 by crosslinking and sliding antiparallel MTs, a novel role for dynein within the framework of spindle assembly.
AB - Mitotic spindle assembly requires the combined activity of various molecular motor proteins, including Eg5 [1] and dynein [2]. Together, these motors generate antagonistic forces during mammalian bipolar spindle assembly [3]; what remains unknown, however, is how these motors are functionally coordinated such that antagonism is possible. Given that Eg5 generates an outward force by crosslinking and sliding apart antiparallel microtubules (MTs) [4-6], we explored the possibility that dynein generates an inward force by likewise sliding antiparallel MTs. We reasoned that antiparallel overlap, and therefore the magnitude of a dynein-mediated force, would be inversely proportional to the initial distance between centrosomes. To capitalize on this relationship, we utilized a nocodazole washout assay to mimic spindle assembly. We found that Eg5 inhibition led to either monopolar or bipolar spindle formation, depending on whether centrosomes were initially separated by less than or greater than 5.5 μm, respectively. Mathematical modeling predicted this same spindle bistability in the absence of functional Eg5 and required dynein acting on antiparallel MTs to do so. Our results suggest that dynein functionally coordinates with Eg5 by crosslinking and sliding antiparallel MTs, a novel role for dynein within the framework of spindle assembly.
KW - CELLBIO
UR - http://www.scopus.com/inward/record.url?scp=71849094525&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=71849094525&partnerID=8YFLogxK
U2 - 10.1016/j.cub.2009.09.025
DO - 10.1016/j.cub.2009.09.025
M3 - Article
C2 - 19836236
AN - SCOPUS:71849094525
SN - 0960-9822
VL - 19
SP - 1833
EP - 1838
JO - Current Biology
JF - Current Biology
IS - 21
ER -