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.
Pubmed ID: 23455152 RIS Download
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Digital microscopy software for research microscopy. It comes standard with drivers to control numerous instruments in and around the microscope. When online, data is acquired in a native-3D format over time, color and specimen locations in customizable experiment protocols. Data can be analyzed by a wide variety of tools for image processing including mathematical operations, statistics functions, analysis scripting and import to/export from MATLAB. Additional modules are available for special applications ranging from deconvolution to photomanipulation to multiphoton.
View all literature mentionsSoftware that detects kinase-specific phosphorylation sites. GPS provides a platform able to perform its prediction based on a group-based phosphorylation scoring algorithm. It allows users to query multiple protein sequences through a batch prediction mode.
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