Targeting tumor-intrinsic MNK1 kinase restricts metabolic flexibility to diminish liver metastasis.
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE232359 | GEO | 2024/11/11
REPOSITORIES: GEO
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Project description:Targeting tumor-intrinsic MNK1 kinase restricts metabolic flexibility to diminish liver metastasis.
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Project description:Although the Mnks have been known for >15 years, their roles in the regulation of protein synthesis have remained obscure. Here we explore how BDNF stimulates protein synthesis in cortical neurons. Using a combination of pharmacological and genetic approaches, we show that this effect depends on MEK/ERK signaling and on the downstream kinase, Mnk1, which phosphorylates eIF4E. Translation initiation is mediated by the interaction of eIF4E with the m7GTP cap of mRNA and with eIF4G. The latter interaction is inhibited by the interactions of eIF4E with partner proteins such as CYFIP1, which together with its partner, FMRP acts as a translational repressor. We find that BDNF induces the release of CYFIP1 from eIF4E, and that this depends on Mnk1. Finally, using a novel combination of BONCAT and SILAC, we identify the a subset of proteins whose synthesis is upregulated by BDNF signalling via Mnk1 in neurons. The This subset of Mnk1-sensitive proteins are enriched for functions involved in neurotransmission and synaptic plasticity. Additionally, we find significant overlap between our subset of Mnk1 Mnk1-sensitive proteins and proteins encoded by known FMRP-binding mRNAs. Taken together, our data implicate Mnk1 as a key component of BDNF-mediated translational regulation in neurons.
2014-11-06 | PXD001074 | Pride
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Project description:The roles of organic additives in the assembly and crystallisation of zeolites are still not fully understood. This is important when attempting to prepare novel frameworks to produce new zeolites. We consider 18-crown-6 ether (18C6) as an additive, which has previously been shown to differentiate between the zeolite EMC-2 (EMT) and faujasite (FAU) frameworks. However, it is unclear whether this distinction is dictated by influences on the metastable free-energy landscape or geometric templating. Using high-pressure synchrotron X-ray diffraction, we have observed that the presence of 18C6 does not impact the EMT framework flexibility-agreeing with our previous geometric simulations and suggesting that 18C6 does not behave as a geometric template. This was further studied by computational modelling using solid-state density-functional theory and lattice dynamics calculations. It is shown that the lattice energy of FAU is lower than EMT, but is strongly impacted by the presence of solvent/guest molecules in the framework. Furthermore, the EMT topology possesses a greater vibrational entropy and is stabilised by free energy at a finite temperature. Overall, these findings demonstrate that the role of the 18C6 additive is to influence the free energy of crystallisation to assemble the EMT framework as opposed to FAU.
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Project description:Dynamic motions of enzymes occurring on a broad range of timescales play a pivotal role in all steps of the reaction pathway, including substrate binding, catalysis, and product release. However, it is unknown whether structural information related to conformational flexibility can be exploited for the directed evolution of enzymes with higher catalytic activity. Here, we show that mutagenesis of residues exclusively located at flexible regions distal to the active site of Homo sapiens kynureninase (HsKYNase) resulted in the isolation of a variant (BF-HsKYNase) in which the rate of the chemical step toward kynurenine was increased by 45-fold. Mechanistic pre–steady-state kinetic analysis of the wild type and the evolved enzyme shed light on the underlying effects of distal mutations (>10 Å from the active site) on the rate-limiting step of the catalytic cycle. Hydrogen-deuterium exchange coupled to mass spectrometry and molecular dynamics simulations revealed that the amino acid substitutions in BF-HsKYNase allosterically affect the flexibility of the pyridoxal-5′-phosphate (PLP) binding pocket, thereby impacting the rate of chemistry, presumably by altering the conformational ensemble and sampling states more favorable to the catalyzed reaction.
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