title: Aurora-A-Dependent Control of TACC3 Influences the Rate of Mitotic Spindle Assembly.
abstract: The essential mammalian gene TACC3 is frequently mutated and amplified in cancers and its fusion products exhibit oncogenic activity in glioblastomas. TACC3 functions in mitotic spindle assembly and chromosome segregation. In particular, phosphorylation on S558 by the mitotic kinase, Aurora-A, promotes spindle recruitment of TACC3 and triggers the formation of a complex with ch-TOG-clathrin that crosslinks and stabilises kinetochore microtubules. Here we map the Aurora-A-binding interface in TACC3 and show that TACC3 potently activates Aurora-A through a domain centered on F525. Vertebrate cells carrying homozygous F525A mutation in the endogenous TACC3 loci exhibit defects in TACC3 function, namely perturbed localization, reduced phosphorylation and weakened interaction with clathrin. The most striking feature of the F525A cells however is a marked shortening of mitosis, at least in part due to rapid spindle assembly. F525A cells do not exhibit chromosome missegregation, indicating that they undergo fast yet apparently faithful mitosis. By contrast, mutating the phosphorylation site S558 to alanine in TACC3 causes aneuploidy without a significant change in mitotic duration. Our work has therefore defined a regulatory role for the Aurora-A-TACC3 interaction beyond the act of phosphorylation at S558. We propose that the regulatory relationship between Aurora-A and TACC3 enables the transition from the microtubule-polymerase activity of TACC3-ch-TOG to the microtubule-crosslinking activity of TACC3-ch-TOG-clathrin complexes as mitosis progresses. Aurora-A-dependent control of TACC3 could determine the balance between these activities, thereby influencing not only spindle length and stability but also the speed of spindle formation with vital consequences for chromosome alignment and segregation.
authors.affiliation: Department of Biochemistry, University of Leicester, Leicester, United Kingdom; Cancer Research UK Leicester Centre, University of Leicester, Leicester, United Kingdom.
authors.forename: Selena G
authors.initials: SG
authors.lastname: Burgess
authors.affiliation: Cancer Research UK Cambridge Institute, Li Ka Shing Centre, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Isabel
authors.initials: I
authors.lastname: Peset
authors.affiliation: Cancer Research UK Cambridge Institute, Li Ka Shing Centre, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Nimesh
authors.initials: N
authors.lastname: Joseph
authors.affiliation: Cell and Developmental Biology program, Centre for Genomic Regulation (CRG), Barcelona, Spain.
authors.forename: Tommaso
authors.initials: T
authors.lastname: Cavazza
authors.affiliation: Cell and Developmental Biology program, Centre for Genomic Regulation (CRG), Barcelona, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Vernos
authors.affiliation: Cardiovascular and Randall Division, King's College London, London, United Kingdom.
authors.forename: Mark
authors.initials: M
authors.lastname: Pfuhl
authors.affiliation: Cancer Research UK Cambridge Institute, Li Ka Shing Centre, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Fanni
authors.initials: F
authors.lastname: Gergely
authors.affiliation: Department of Biochemistry, University of Leicester, Leicester, United Kingdom; Cancer Research UK Leicester Centre, University of Leicester, Leicester, United Kingdom.
authors.forename: Richard
authors.initials: R
authors.lastname: Bayliss
mesh_terms: D000782:Aneuploidy; D000818:Animals; D064096:Aurora Kinase A / Q000378:metabolism*; D001665:Binding Sites / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics*; D045744:Cell Line, Tumor; D002645:Chickens; D020090:Chromosome Segregation / Q000235:genetics; D002966:Clathrin / Q000378:metabolism; D005326:Fetal Proteins / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D018386:Kinetochores; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000235:genetics*; D008870:Microtubules / Q000378:metabolism; D008938:Mitosis / Q000235:genetics; D010766:Phosphorylation / Q000235:genetics; D011485:Protein Binding / Q000235:genetics; D017434:Protein Structure, Tertiary; D008941:Spindle Apparatus / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics*; D029867:Xenopus Proteins / Q000235:genetics*; D014982:Xenopus laevis
chemical_list: D002352:Carrier Proteins; D002966:Clathrin; D005326:Fetal Proteins; D008869:Microtubule-Associated Proteins; C474872:TACC3 protein, Xenopus; C120551:TACC3 protein, human; C418485:TACC3 protein, mouse; D014157:Transcription Factors; D029867:Xenopus Proteins; D064096:Aurora Kinase A