title: A stringent requirement for Plk1 T210 phosphorylation during K-fiber assembly and chromosome congression.
abstract: Polo-like kinase 1 (Plk1) is an essential mitotic regulator and undergoes periodic phosphorylation on threonine 210, a conserved residue in the kinase's activation loop. While phosphate-mimicking alterations of T210 stimulate Plk1's kinase activity in vitro, their effects on cell cycle regulation in vivo remain controversial. Using gene targeting, we replaced the native PLK1 locus in human cells with either PLK1                 (T210A) or PLK1                 (T210D) in both dominant and recessive settings. In contrast to previous reports, PLK1                 (T210D) did not accelerate cells prematurely into mitosis, nor could it fulfill the kinase's essential role in chromosome congression. The latter was traced to an unexpected defect in Plk1-dependent phosphorylation of BubR1, a key mediator of stable kinetochore-microtubule attachment. Using chemical genetics to bypass this defect, we found that Plk1(T210D) is nonetheless able to induce equatorial RhoA zones and cleavage furrows during mitotic exit. Collectively, our data indicate that K-fibers are sensitive to even subtle perturbations in T210 phosphorylation and caution against relying on Plk1(T210D) as an in vivo surrogate for the natively activated kinase.
authors.affiliation: Weill Graduate School of Medical Sciences, Cornell University, New York, NY 10065, USA.
authors.forename: Catherine Randall
authors.initials: CR
authors.lastname: Paschal
authors.forename: John
authors.initials: J
authors.lastname: Maciejowski
authors.forename: Prasad V
authors.initials: PV
authors.lastname: Jallepalli
mesh_terms: D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line / Q000187:drug effects; D045584:Chromosome Positioning; D002877:Chromosomes, Human / Q000235:genetics / Q000378:metabolism*; D055786:Gene Knockout Techniques; D006801:Humans; D018386:Kinetochores / Q000378:metabolism; D008938:Mitosis; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D011743:Pyrimidines / Q000494:pharmacology; D013871:Thiones / Q000494:pharmacology; D013912:Threonine / Q000378:metabolism*; D020742:rhoA GTP-Binding Protein / Q000235:genetics / Q000378:metabolism; D000097869:Polo-Like Kinase 1
chemical_list: D018797:Cell Cycle Proteins; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D011743:Pyrimidines; D013871:Thiones; D013912:Threonine; D020742:rhoA GTP-Binding Protein; D000097869:Polo-Like Kinase 1; C066737:RHOA protein, human; C400223:monastrol; C584277:BUB1 protein, human; C090464:Bub1 spindle checkpoint protein