Martin Wühr

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Size specification of macromolecular assemblies in the cytoplasm is poorly understood [1]. In principle, assemblies could scale with cell size or use intrinsic mechanisms. For the mitotic spindle, scaling with cell size is expected, because the function of this assembly is to physically move sister chromatids into the center of nascent daughter cells. Eggs(More)
Current models for cleavage plane determination propose that metaphase spindles are positioned and oriented by interactions of their astral microtubules with the cellular cortex, followed by cleavage in the plane of the metaphase plate [1, 2]. We show that in early frog and fish embryos, where cells are unusually large, astral microtubules in metaphase are(More)
Protein interactions form a network whose structure drives cellular function and whose organization informs biological inquiry. Using high-throughput affinity-purification mass spectrometry, we identify interacting partners for 2,594 human proteins in HEK293T cells. The resulting network (BioPlex) contains 23,744 interactions among 7,668 proteins with 86%(More)
Microtubules play a central role in centering the nucleus or mitotic spindle in eukaryotic cells. However, despite common use of microtubules for centering, physical mechanisms can vary greatly, and depend on cell size and cell type. In the small fission yeast cells, the nucleus can be centered by pushing forces that are generated when growing microtubules(More)
Separase not only triggers anaphase of meiosis I by proteolytic cleavage of cohesin on chromosome arms, but in vitro vertebrate separase also acts as a direct inhibitor of cyclin-dependent kinase 1 (Cdk1) on liberation from the inhibitory protein, securin. Blocking separase-Cdk1 complex formation by microinjection of anti-separase antibodies prevents(More)
Multiplexed quantitation via isobaric chemical tags (e.g., tandem mass tags (TMT) and isobaric tags for relative and absolute quantitation (iTRAQ)) has the potential to revolutionize quantitative proteomics. However, until recently the utility of these tags was questionable due to reporter ion ratio distortion resulting from fragmentation of coisolated(More)
BACKGROUND Mass spectrometry-based proteomics enables the global identification and quantification of proteins and their posttranslational modifications in complex biological samples. However, proteomic analysis requires a complete and accurate reference set of proteins and is therefore largely restricted to model organisms with sequenced genomes. RESULTS(More)
The composition of the nucleoplasm determines the behavior of key processes such as transcription, yet there is still no reliable and quantitative resource of nuclear proteins. Furthermore, it is still unclear how the distinct nuclear and cytoplasmic compositions are maintained. To describe the nuclear proteome quantitatively, we isolated the large nuclei(More)
Most vertebrate oocytes contain a Balbiani body, a large, non-membrane-bound compartment packed with RNA, mitochondria, and other organelles. Little is known about this compartment, though it specifies germline identity in many non-mammalian vertebrates. We show Xvelo, a disordered protein with an N-terminal prion-like domain, is an abundant constituent of(More)
Small heat shock proteins (sHsps) are molecular chaperones that specifically bind non-native proteins and prevent them from irreversible aggregation. A key trait of sHsps is their existence as dynamic oligomers. Hsp26 from Saccharomyces cerevisiae assembles into a 24mer, which becomes activated under heat shock conditions and forms large, stable substrate(More)