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Proud C.G.,University of Southampton | Proud C.G.,South Australian Health and Medical Research Institute
Biochemical Society Transactions

Eukaryotic elongation factor 2 kinase (eEF2K) belongs to the small family of atypical protein kinases termed α-kinases, and is the only calcium/calmodulin (Ca/CaM)-dependent member of that group. It phosphorylates and inactivates eEF2, to slow down the rate of elongation, the stage in mRNA translation that consumes almost all the energy and amino acids consumed by protein synthesis. In addition to activation by Ca/CaM, eEF2K is also regulated by an array of other regulatory inputs, which include inhibition by the nutrient- and growth-factor activated signalling pathways. Recent evidence shows that eEF2K plays an important role in learning and memory, processes that require the synthesis of new proteins and involve Ca-mediated signalling. eEF2K is activated under conditions of nutrient and energy depletion. In cancer cells, or certain tumours, eEF2K exerts cytoprotective effects, which probably reflect its ability to inhibit protein synthesis, and nutrient consumption, under starvation conditions. eEF2K is being evaluated as a potential therapeutic target in cancer. © The Authors Journal compilation © 2015 Biochemical Society. Source

Proud C.G.,South Australian Health and Medical Research Institute
Biochimica et Biophysica Acta - Gene Regulatory Mechanisms

The MAP kinase signal-integrating kinases or MAP kinase-interacting protein kinases (Mnks) are activated by signaling through the oncogenic MAP kinase (ERK) pathway. The best-known Mnk substrate is eukaryotic initiation factor eIF4E, the protein which binds the 5'-cap structure of eukaryotic mRNAs and helps to recruit ribosomes to them. eIF4E is a well-established proto-oncogene, whose expression or activation is associated with transformation and tumorigenesis. Mnks phosphorylate eIF4E at a single site. Increasing evidence implicates the Mnks and/or phosphorylation of eIF4E in cell transformation, tumorigenesis or tumor progression, in a growing range of settings. Mnks and/or the phosphorylation of eIF4E have been suggested to regulate the expression of proteins involved in cell cycle progression, cell survival and cell motility. Further work is needed to extend our understanding of the impact of the Mnks on gene expression, explore the biochemical mechanisms involved and evaluate the utility of targeting the Mnks in cancer therapy. This article is part of a Special Issue entitled: Translation and Cancer. © 2014 Elsevier B.V. Source

Fedele A.O.,South Australian Health and Medical Research Institute
Application of Clinical Genetics

Sanfilippo syndrome, or mucopolysaccharidosis (MPS) type III, refers to one of five autosomal recessive, neurodegenerative lysosomal storage disorders (MPS IIIA to MPS IIIE) whose symptoms are caused by the deficiency of enzymes involved exclusively in heparan sulfate degradation. The primary characteristic of MPS III is the degeneration of the central nervous system, resulting in mental retardation and hyperactivity, typically commencing during childhood. The significance of the order of events leading from heparan sulfate accumulation through to downstream changes in the levels of biomolecules within the cell and ultimately the (predominantly neuropathological) clinical symptoms is not well understood. The genes whose deficiencies cause the MPS III subtypes have been identified, and their gene products, as well as a selection of disease-causing mutations, have been characterized to varying degrees with respect to both frequency and direct biochemical consequences. A number of genetic and biochemical diagnostic methods have been developed and adopted by diagnostic laboratories. However, there is no effective therapy available for any form of MPS III, with treatment currently limited to clinical management of neurological symptoms. The availability of animal models for all forms of MPS III, whether spontaneous or generated via gene targeting, has contributed to improved understanding of the MPS III subtypes, and has provided and will deliver invaluable tools to appraise emerging therapies. Indeed, clinical trials to evaluate intrathecally-delivered enzyme replacement therapy in MPS IIIA patients, and gene therapy for MPS IIIA and MPS IIIB patients are planned or underway. © 2015 Fedele. Source

Kentish S.J.,University of Adelaide | Page A.J.,University of Adelaide | Page A.J.,South Australian Health and Medical Research Institute
Journal of Physiology

Gastrointestinal (GI) vagal afferents are a key mediatory of food intake. Through a balance of responses to chemical and mechanical stimuli food intake can be tightly controlled via the ascending satiety signals initiated in the GI tract. However, vagal responses to both mechanical and chemical stimuli are modified in diet-induced obesity (DIO). Much of the research to date whilst in relatively isolated/controlled circumstances indicates a shift between a balance of orexigenic and anorexigenic vagal signals to blunted anorexigenic and potentiated orexigenic capacity. Although the mechanism responsible for the DIO shift in GI vagal afferent signalling is unknown, one possible contributing factor is the gut microbiota. Nevertheless, whatever the mechanism, the observed changes in gastrointestinal vagal afferent signalling may underlie the pathophysiological changes in food consumption that are pivotal for the development and maintenance of obesity. Gastrointestinal vagal afferents play an important role in food intake regulation. In individuals on a healthy balanced diet the anorexigenic and orexigenic signals from the gastrointestinal are finely balanced to maintain a steady weight. However, under high fat diet conditions this balance is disrupted with orexigenic signals out weighing anorexigenic signals, leading to increased food intake and body mass. © 2014 The Physiological Society. Source

Agency: Cordis | Branch: FP7 | Program: CP-IP | Phase: HEALTH.2011.2.1.1-2 | Award Amount: 15.99M | Year: 2011

PRIMES focuses on the role of protein interactions to assemble dynamic molecular machines that receive and process information to coordinate cellular responses. PRIMES investigates the following: (i) How do protein interactions contribute to the generation of biological specificity in signalling? (ii) How do pathogenetic perturbations affect protein interaction networks? (iii) How can we exploit protein interactions as therapeutic targets? We focus on the EGFR/ERBB signalling network and its role in colorectal cancer (CRC), the third most frequent cancer. The ERBB network is frequently altered in CRC either through overexpression or mutation of the receptors or downstream components. Network components have become important drug targets. Poor response rates and resistance demonstrate we lack sufficient insight to design efficacious therapies. Using proteomics, structural biology, advanced imaging and mathematical modelling we (i) map static and dynamic protein interactions in the ERBB network (ii) unravel the design principles and emergent network properties conferred by protein interactions; and (iii) validate these findings in genetic mouse models of CRC and human tissues. PRIMES aims to (i) enhance the functional pathogenetic understanding of CRC (ii) identify mechanisms of drug resistance and drug efficacy; and (iii) identify drugs that affect protein interactions to rationally manipulate network functions related to individual genetic mutations. Outcomes include (i) a dynamic, mechanistic flowchart of how protein interactions compute biochemical and biological specificity in signalling networks (ii) a functional protein interaction network of healthy and oncogenic ERBB signalling validated in mouse models of CRC and human tissues (iii) network level insights towards personalised CRC treatment based on genotype-phenotype relationships; and (iv) chemical compounds targeting protein interactions to restore normal ERBB network function or break oncogenic circuits.

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