title: Dynactin helps target Polo-like kinase 1 to kinetochores via its left-handed beta-helical p27 subunit.
abstract: Dynactin is a protein complex required for the in vivo function of cytoplasmic dynein, a microtubule (MT)-based motor. Dynactin binds both dynein and MTs via its p150(Glued) subunit, but little is known about the 'pointed-end complex' that includes the protein subunits Arp11, p62 and the p27/p25 heterodimer. Here, we show that the p27/p25 heterodimer undergoes mitotic phosphorylation by cyclin-dependent kinase 1 (Cdk1) at a single site, p27 Thr186, to generate an anchoring site for polo-like kinase 1 (Plk1) at kinetochores. Removal of p27/p25 from dynactin results in reduced levels of Plk1 and its phosphorylated substrates at kinetochores in prometaphase, which correlates with aberrant kinetochore-MT interactions, improper chromosome alignment and abbreviated mitosis. To investigate the structural implications of p27 phosphorylation, we determined the structure of human p27. This revealed an unusual left-handed β-helix domain, with the phosphorylation site located within a disordered, C-terminal segment. We conclude that dynactin plays a previously undescribed regulatory role in the spindle assembly checkpoint by recruiting Plk1 to kinetochores and facilitating phosphorylation of important downstream targets.
authors: Department of Biology, Johns Hopkins University, Baltimore, MD, USA.
authors: Ting-Yu
authors: TY
authors: Yeh
authors: Anna K
authors: AK
authors: Kowalska
authors: Brett R
authors: BR
authors: Scipioni
authors: Frances Ka Yan
authors: FK
authors: Cheong
authors: Meiying
authors: M
authors: Zheng
authors: Urszula
authors: U
authors: Derewenda
authors: Zygmunt S
authors: ZS
authors: Derewenda
authors: Trina A
authors: TA
authors: Schroer
mesh_terms: D000818:Animals; D002417:Cattle; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002642:Chick Embryo; D000072159:Dynactin Complex; D006801:Humans; D018386:Kinetochores / Q000378:metabolism*; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D008941:Spindle Apparatus / Q000235:genetics / Q000378:metabolism; D000097869:Polo-Like Kinase 1
chemical_list: D018797:Cell Cycle Proteins; D000072159:Dynactin Complex; D008869:Microtubule-Associated Proteins; D017346:Protein Serine-Threonine Kinases; D021122:Protein Subunits; D011518:Proto-Oncogene Proteins; D000097869:Polo-Like Kinase 1; C000606360:DCTN1 protein, human; C000606364:Dctn1 protein, mouse