PP2A-Rts1 antagonizes Rck2-mediated hyperosmotic stress signaling in yeast
Ontology highlight
ABSTRACT:
INSTRUMENT(S): LTQ Orbitrap Velos, Q Exactive HF
ORGANISM(S): Saccharomyces Cerevisiae (baker's Yeast)
SUBMITTER: 
David Hollenstein
LAB HEAD: Wolfgang Reiter
PROVIDER: PXD019647 | Pride | 2022-05-16
REPOSITORIES: Pride
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Project description:Pulmonary exposure to high doses of nanoparticles (NP) leads to well characterized lung toxicity in addition to long-term NP retention. However, pulmonary NP accumulation and toxicity following low dose exposures are not well described. In the present study we sought to: (1) investigate particle retention in mouse lungs following intratracheal instillation of varying doses of nano-sized titanium dioxide (nano-TiO2) and (2) determine the effects of long-term particle accumulation on pulmonary systems. Female C57BL/6 mice were exposed to rutile nano-TiO2 (primary size of 20.6 nm and surface area of 107.7 m2/g) via single intratracheal instillations of 18, 54 and 162 M-BM-5g/mouse and sampled 1, 3 and 28 days post-exposure. The deposition of nano-TiO2 in the lungs was assessed using Nanoscale Hyperspectral Microscope. DNA microarrays, pathway-specific real-time RT-PCR (qPCR) and gene-specific qPCR arrays, and tissue protein analyses were employed to characterize pulmonary responses. Hyperspectral mapping showed dose-dependent retention of nano-TiO2 in the lungs up to 28 days post-exposure time. Retention did not correlate with the extent of inflammatory neutrophil influx into the lungs. DNA microarray analysis showed altered expression of approximately 3000 genes across all treatment groups (M-BM-11.3 fold; p<0.1). Several inflammatory mediators changed in a dose- and time-dependent manner at both the mRNA and protein levels. Although the low dose exposure failed to induce observable inflammation, significant changes in the expression of genes and proteins associated with inflammation were observed. Moreover, diminished (or absent) neutrophil influx in the low and medium dose groups was correlated with negative regulation of genes associated with ion homeostasis and muscle regulation. Gene expression changes for several inflammatory mediators have previously been noted in mice exposed to the same nano-TiO2 via inhalation. Our results suggest that retention of nano-TiO2 in the absence of inflammation and effective clearance can perturb calcium and ion homeostasis, and affect smooth muscle activities over time. This experiment consists of three different dosages of TiO2, e.g., low (18 ug), medium (54 ug) and high (162 ug), and one control. There are 3 time points for each treatment and control group, e.g., day 1, day 3 and day 28. Each dose or time point has 5-6 biological replicates. There are total 65 samples (arrays)
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Project description:MASTL, also known as Greatwall, was originally characterized in flies and Xenopus as a mitotic kinase involved in the maintenance of the mitotic state by inhibiting PP2A-B55 complexes. A specific mutation (E167D) in the human MASTL gene was simultaneously linked to autosomal dominant thrombocytopenia. However, the possible connections between the cell cycle machinery and this human disease remain unexplored. By analyzing genetically-engineered mice with specific ablation of Mastl in megakaryocytes and platelets we report here that Mastl ablation results in defective megakaryocyte maturation and reduced platelet counts. Platelet counts are also reduced in a new Mastl E166D knockin model carrying the thrombocytopenia-associated mutation in the murine locus. Surprisingly, thrombocytopenia in this model is not due to defective megakaryocyte maturation, but a consequence of aberrant activation and reduced survival of platelets. Stimulation of Mastl E166D platelets is characterized by rapid formation of hyper-stabilized pseudopods similarly to cells in which PP2A activity is chemically inhibited. These defects are accompanied by abnormal phosphorylation of multiple components of the actin cytoskeleton and can be rescued both in vitro and in vivo by inhibiting upstream kinases such as PKA, PKC or AMPK. These results suggest that Mastl E166D is a dominant mutation that may contribute to thrombocytopenia by altering the phosphorylation status of several molecular pathways critical in platelet cytoskeletal dynamics. These data reveal an unexpected role of Mastl in the control of cytoskeleton dynamics in a cell-cycle independent manner in nucleus-depleted, terminally differentiated cells.
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