title: Marking and measuring single microtubules by PRC1 and kinesin-4.
abstract: Error-free cell division depends on the assembly of the spindle midzone, a specialized array of overlapping microtubules that emerges between segregating chromosomes during anaphase. The molecular mechanisms by which a subset of dynamic microtubules from the metaphase spindle are selected and organized into a stable midzone array are poorly understood. Here, we show using in vitro reconstitution assays that PRC1 and kinesin-4, two microtubule-associated proteins required for midzone assembly, can tag microtubule plus ends. Remarkably, the size of these tags is proportional to filament length. We determine the crystal structure of the PRC1 homodimer and map the protein-protein interactions needed for tagging microtubule ends. Importantly, length-dependent microtubule plus-end-tagging by PRC1 is also observed in dividing cells. Our findings suggest how biochemically similar microtubules can be differentially marked, based on length, for selective regulation during the formation of specialized arrays, such as those required for cytokinesis.
authors.affiliation: Laboratory of Chemistry and Cell Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
authors.forename: Radhika
authors.initials: R
authors.lastname: Subramanian
authors.forename: Shih-Chieh
authors.initials: SC
authors.lastname: Ti
authors.forename: Lei
authors.initials: L
authors.lastname: Tan
authors.forename: Seth A
authors.initials: SA
authors.lastname: Darst
authors.forename: Tarun M
authors.initials: TM
authors.lastname: Kapoor
mesh_terms: D000595:Amino Acid Sequence; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000378:metabolism*; D018360:Crystallography, X-Ray; D048749:Cytokinesis; D019281:Dimerization; D006801:Humans; D016547:Kinesins / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016415:Sequence Alignment
chemical_list: D018797:Cell Cycle Proteins; C116662:PRC1 protein, human; C484228:KIF4A protein, human; D016547:Kinesins