| 1. |
- Jakobsen, Lis, et al.
(författare)
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Novel asymmetrically localizing components of human centrosomes identified by complementary proteomics methods
- 2011
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Ingår i: EMBO Journal. - : Wiley. - 0261-4189 .- 1460-2075. ; 30:8, s. 1520-1535
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Tidskriftsartikel (refereegranskat)abstract
- Centrosomes in animal cells are dynamic organelles with a proteinaceous matrix of pericentriolar material assembled around a pair of centrioles. They organize the microtubule cytoskeleton and the mitotic spindle apparatus. Mature centrioles are essential for biogenesis of primary cilia that mediate key signalling events. Despite recent advances, the molecular basis for the plethora of processes coordinated by centrosomes is not fully understood. We have combined protein identification and localization, using PCP-SILAC mass spectrometry, BAC transgeneOmics, and antibodies to define the constituents of human centrosomes. From a background of non-specific proteins, we distinguished 126 known and 40 candidate centrosomal proteins, of which 22 were confirmed as novel components. An antibody screen covering 4000 genes revealed an additional 113 candidates. We illustrate the power of our methods by identifying a novel set of five proteins preferentially associated with mother or daughter centrioles, comprising genes implicated in cell polarity. Pulsed labelling demonstrates a remarkable variation in the stability of centrosomal protein complexes. These spatiotemporal proteomics data provide leads to the further functional characterization of centrosomal proteins.
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| 2. |
- Groth, Anja, et al.
(författare)
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Human Tousled like kinases are targeted by an ATM- and Chk1-dependent DNA damage checkpoint
- 2003
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Ingår i: EMBO Journal. - : Wiley. - 0261-4189 .- 1460-2075. ; 22:7, s. 1676-1687
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Tidskriftsartikel (refereegranskat)abstract
- All eukaryotes respond to DNA damage by modulation of diverse cellular processes to preserve genomic integrity and ensure survival. Here we identify mammalian Tousled like kinases (Tlks) as a novel target of the DNA damage checkpoint. During S-phase progression, when Tlks are maximally active, generation of DNA double-strand breaks (DSBs) leads to rapid and transient inhibition of Tlk activity. Experiments with chemical inhibitors, genetic models and gene targeting through RNA interference demonstrate that this response to DSBs requires ATM and Chk1 function. Chk1 phosphorylates Tlk1 on serine 695 (S695) in vitro, and this UCN-01- and caffeine-sensitive site is phosphorylated in vivo in response to DNA damage. Substitution of S695 to alanine impaired efficient downregulation of Tlk1 after DNA damage. These findings identify an unprecedented functional co- operation between ATM and Chk1 in propagation of a checkpoint response during S phase and suggest that, through transient inhibition of Tlk kinases, the ATM-Chk1-Tlk pathway may regulate processes involved in chromatin assembly.
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