About the Project
A 3-year PhD project is available in Strathclyde Institute of Pharmacy and Biomedical Sciences (SIPBS) at University of Strathclyde. This PhD project will concern the role of sphingosine kinase 1 in regulating synaptic transmission and synaptic spread.
The enzyme, sphingosine kinase 1 (SK1) which catalyses formation of a bioactive lipid (sphingosine 1-phosphate) is recruited into early endocytic vesicles in neurons. This requires the unmasking of an anionic phospholipid binding site in SK1 to facilitate its membrane recruitment. The relevance of this is that SK1 has been identified in promoting acetylcholine release at the neuromuscular junction in the model organism, Caenorhabditis elgans. Indeed, wild type SK1 but not a mutant SK1 (deficient in binding to the plasma-membrane) rescues a neurotransmission defect in SK1 mutant worms. The objective of the PhD is to investigate the interaction between SK1 and the G-protein, Gq, which we propose underlies the mechanism of SK1 membrane recruitment. This will involve analysis of synaptic vesicle recycling in mammalian and Caenorhabditis elgans neurones. Findings from these studies might provide novel targets for rectifying the cholinergic deficit in Alzheimer’s disease. In addition, a better understanding of the mechanism regulating membrane targeting of SK1 will provide information concerning ‘synaptic spread’ where aggregated forms of Tau and -amyloid are transferred via synaptic communication leading to their spread throughout the brain. S1P is involved in regulating synaptic activity and is therefore important in the disease pathology. The project will employ cell culture, site directed mutagenesis, Western blotting, biochemical SK1 assays, molecular modelling, measurement of acetylcholine/Tau/-amyloid release and miniature excitatory postsynaptic currents, development of transgenic Caenorhabditis elgans expressing WT or mutant SK1, confocal imaging, and proteomic analysis.
Techniques to be used:
Cell Culture, site directed mutagenesis, Western blotting, biochemical sphingosine kinase 1 assays, molecular modelling, measurement of acetylcholine release and miniature excitatory postsynaptic currents (mEPSCs), development of transgenic Caenorhabditis elgans with WT and mutant SK1, confocal imaging, and proteomic analysis
This project is a collaborative PhD project between Professors Nigel Pyne and Susan Pyne at University of Strathclyde and Professors Yung Hou Wong and Karl Wah-Keung Tsim at Hong Kong University of Science and Technology (HKUST, China). While this project will be conducted primarily at University of Strathclyde, the student will spend at least 6 months at HKUST to acquire new skills and produce data that will contribute to his/her PhD.
Funding Notes
This project is fully funded (Home / EU tuition fees and stipend at RCUK rates) for three years by the University’s strategic initiative for this collaborative PhD programme.
The successful candidate should have or expect to have an Honours Degree at 2.1 or above (or equivalent) in Biochemistry, Pharmacology, Genetics and/or Molecular Biology. Candidates may send their application to Professor NJ Pyne ([Email Address Removed]), including a CV and cover letter, detailing their motivation for this particular PhD project.
References
Adams, DR, Pyne, S & Pyne, NJ. (2016) Sphingosine kinases: emerging structure function insights. Trends Biochem. (in press).
Lim, K-G, Tonelli, F, Li, Z, Lu, X, Bittman, R, Pyne, S & Pyne, NJ. (2011) FTY720 analogues as sphingosine kinase 1 inhibitors: enzyme inhibition kinetics, allosterism, proteasomal degradation and actin rearrangement in MCF-7 breast cancer cells. J. Biol. Chem. 286, 18633-18640.
Hengst JA, Guilford JM, Conroy EJ, Wang X, Yun JK. (2010) Enhancement of sphingosine kinase 1 catalytic activity by deletion of 21 amino acids from the COOH-terminus. Arch Biochem Biophys. 494:23-31.
ter Braak M, Danneberg K, Lichte K, Liphardt K, Ktistakis NT, Pitson SM, Hla T, Jakobs KH, Meyer zu Heringdorf D. (2009) Galpha(q)-mediated plasma membrane translocation of sphingosine kinase-1 and cross-activation of S1P receptors. Biochim Biophys Acta. 1791:357-70.
Chan JP, Hu Z, Sieburth D. (2012) Recruitment of sphingosine kinase to presynaptic terminals by a conserved muscarinic signaling pathway promotes neurotransmitter release. Genes Dev. 26:1070-85.
Shen H, Giordano F, Wu Y, Chan J, Zhu C, Milosevic I, Wu X, Yao K, Chen B, Baumgart T, Sieburth D, De Camilli P. (2014) Coupling between endocytosis and sphingosine kinase 1 recruitment. Nat Cell Biol. 16:652-62.
Francis PT, Palmer AM, Snape M, Wilcock GK. (1999) The cholinergic hypothesis of Alzheimer's disease: a review of progress. J Neurol Neurosurg Psychiatry. 66:137-47.
Liu L, Drouet V, Wu JW, Witter MP, Small SA, Clelland C, Duff K. (2012) Trans-synaptic spread of tau pathology in vivo. PLoS One. 7:e31302.
Kajimoto T, Okada T, Miya S, Zhang L, Nakamura S. (2013) Ongoing activation of sphingosine 1-phosphate receptors mediates maturation of exosomal multivesicular endosomes. Nat Commun. 4:2712