title: The rise and fall of the phragmoplast microtubule array.
abstract: The cytokinetic apparatus, the phragmoplast, contains a bipolar microtubule (MT) framework that has the MT plus ends concentrated at or near the division site. This anti-parallel MT array provides tracks for the transport of Golgi-derived vesicles toward the plus ends so that materials enclosed are subsequently deposited at the division site. Here we will discuss a proposed model of the centrifugal expansion of the phragmoplast that takes place concomitantly with the assembly of the cell plate, the ultimate product of vesicle fusion. The expansion is a result of continuous MT assembly at the phragmoplast periphery while the MTs toward the center of the phragmoplast are disassembled. These events are the result of MT-dependent MT polymerization, bundling of anti-parallel MTs coming from opposite sides of the division plane that occurs selectively at the phragmoplast periphery, positioning of the plus ends of cross-linked MTs at or near the division site by establishing a minimal MT-overlapping zone, and debundling of anti-parallel MTs that is triggered by phosphorylation of MT-associated proteins. The debundled MTs are disassembled at last by factors including the MT severing enzyme katanin.
authors.affiliation: Department of Plant Biology, University of California, Davis, CA 95616, USA.
authors.forename: Yuh-Ru Julie
authors.initials: YR
authors.lastname: Lee
authors.forename: Bo
authors.initials: B
authors.lastname: Liu
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism*; D048749:Cytokinesis; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism*; D008954:Models, Biological; D059828:Plant Cells / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism; D022161:Transport Vesicles / Q000378:metabolism
chemical_list: D008869:Microtubule-Associated Proteins; D010940:Plant Proteins