title: Deubiquitination of γ-tubulin by BAP1 prevents chromosome instability in breast cancer cells.
abstract: Microtubule nucleation requires the γ-tubulin ring complex, and during the M-phase (mitosis) this complex accumulates at the centrosome to support mitotic spindle formation. The posttranslational modification of γ-tubulin through ubiquitination is vital for regulating microtubule nucleation and centrosome duplication. Blocking the BRCA1/BARD1-dependent ubiquitination of γ-tubulin causes centrosome amplification. In the current study, we identified BRCA1-associated protein-1 (BAP1) as a deubiquitination enzyme for γ-tubulin. BAP1 was downregulated in metastatic adenocarcinoma breast cell lines compared with noncancerous human breast epithelial cells. Furthermore, low expression of BAP1 was associated with reduced overall survival of patients with breast cancer. Reduced expression of BAP1 in breast cancer cell lines was associated with mitotic abnormalities. Importantly, rescue experiments including expression of full length but not the catalytic mutant of BAP1 reduced ubiquitination of γ-tubulin and prevented mitotic defects. Our study uncovers a new mechanism for BAP1 involved in deubiquitination of γ-tubulin, which is required to prevent abnormal mitotic spindle formation and genome instability.
authors.affiliation: Department of Laboratory Medicine, Translational Cancer Research, Lund University, Medicon Village, Lund, Sweden.
authors.forename: Reihaneh
authors.initials: R
authors.lastname: Zarrizi
authors.affiliation: Department of Clinical Sciences, Section of Oncology-Pathology, Lund University, Lund, Sweden.
authors.forename: Julien Albert
authors.initials: JA
authors.lastname: Menard
authors.affiliation: Department of Clinical Sciences, Section of Oncology-Pathology, Lund University, Lund, Sweden. Department of Oncology, Skåne University Hospital, Lund, Sweden.
authors.forename: Mattias
authors.initials: M
authors.lastname: Belting
authors.affiliation: Department of Laboratory Medicine, Translational Cancer Research, Lund University, Medicon Village, Lund, Sweden. Ramin.Massoumi@med.lu.se.
authors.forename: Ramin
authors.initials: R
authors.lastname: Massoumi
mesh_terms: D002453:Cell Cycle; D045744:Cell Line, Tumor; D002869:Chromosome Aberrations; D005260:Female; D006801:Humans; D008941:Spindle Apparatus / Q000502:physiology; D014404:Tubulin / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000502:physiology*; D043222:Ubiquitin Thiolesterase / Q000502:physiology*; D054875:Ubiquitination
chemical_list: C400134:BAP1 protein, human; D014404:Tubulin; D025521:Tumor Suppressor Proteins; D043222:Ubiquitin Thiolesterase