%0 Journal Article
%T Localization and function of Kinesin-5-like proteins during assembly and maintenance of mitotic spindles in Silvetia compressa
%A Nick T Peters
%A Anne Miller
%A Darryl L Kropf
%J BMC Research Notes
%D 2009
%I BioMed Central
%R 10.1186/1756-0500-2-106
%X Anti-Eg5 antibodies were used to investigate localization of Kinesin-5-like proteins in brown algal zygotes. In interphase zygotes, localization was predominantly within the nucleus. As zygotes entered mitosis, these motor proteins strongly associated with spindle poles and, to a lesser degree, with the polar microtubule arrays and the spindle midzone. In order to address whether Kinesin-5-like proteins are required to maintain spindle bipolarity, we applied monastrol to synchronized zygotes containing bipolar spindles. Monastrol is a cell-permeable chemical inhibitor of the Kinesin-5 class of molecular motors. We found that inhibition of motor function in pre-formed spindles induced the formation of multipolar spindles and short bipolar spindles.Based upon these localization and inhibitor studies, we conclude that Kinesin-5-like motors in brown algae are more similar to the motors of animals than those of plants or protists. However, Kinesin-5-like proteins in S. compressa serve novel roles in spindle formation and maintenance not observed in animals.Kinesins are a diverse group of molecular motors present in protozoans, fungi, plants, and metazoans [1]. They share a globular motor domain that hydrolyses ATP to facilitate movement towards the plus or minus end of microtubules [2]. Kinesins participate in structural organization and/or stabilization of microtubules and also transport cargo throughout the cytoplasm utilizing microtubules as molecular highways [2]. The Kinesin-5 group of the kinesin superfamily consists of plus-end directed homotetramers with two motor domains on each end [1]. They have been shown to function in spindle organization during mitosis in animal cells, remaining inactive and sequestered within the nucleus during interphase [1]. Specifically, Kinesin-5 motors are thought to function at the spindle midzone and maintain spindle bipolarity by walking towards the plus ends of interdigitating microtubules from opposite poles [3]. Kinesin-5 motor
%U http://www.biomedcentral.com/1756-0500/2/106