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Molecular &
Cellular Physiology
Laboratory

secretion, hormone release, exocytosis, endocrine cell biology, cell signalling...

Dynamin co-localises with vesicles, as demonstrated
with co-localisation of dynamin protein with NPY

Research Summary

Our research is focused on the regulation of cell communication. Specifically we are interested in identifying new molecules which regulate the release of neurotransmitters and hormones. As well as this, we have a significant focus on how cell signalling is altered in human health disorders such as Type 2 Diabetes and obesity. We utilise human primary cells, genetically modified mice and molecular biology approaches, enabling us to investigate the role of specific proteins from the whole animal, single cell and single vesicle level.

These studies are carried out using a number of approaches including physiological measurements of exocytosis from single cells with carbon fibre amperometry, or by whole cell capacitance measurements and by the measurement of ion channel currents using patch clamp electrophysiology. We also carry out transfection of cells with GFP-tagged mutant constructs, immunohistochemistry, live cell imaging, real time RT-PCR, measurement of mitochondrial activity and culturing of primary cells and cell lines. These are complimented with whole animal in vivo studies including metabolic profiling of transgenic and knockout mouse lines.

Research Projects

Gut endocrine cells are scattered throughout the lining of our gastrointestinal tract. They include cells that synthesise and secrete a variety of different hormones. While these cells represent our largest endocrine organ inn the body, we know little about how they function, especially in humans. These hormones have important roles in metabolism and obesity (eg; GLP-1, PYY, serotonin, GIP, ghrelin) that effect different targets. Some of these hormones, for example, tell our brain to start or stop eating, while others make us fat and others trigger insulin secretion. Several of these hormones are the target of current and emerging therapeutics for the treatment of type 2 diabetes and obesity.  We have developed methods to isolate specific populations of these cells from humans and rodents and to study the mechanisms that control gut hormone release in human tissue (Sun et al . We work with major international research centres and pharmaceutical companies to understand how to control gut hormone release with a view to developing the next generation of treatments for human metabolic disorders.

One of the core research areas in our group is identifying novel regulators of exocytosis, the process by which secretory vesicles fuse with the plasma membrane to release contents such as hormones and neurotransmitters. We use single cell electrochemistry and electrophysiology techniques to analyse the release of neurotransmitters and hormones at the level of single vesicle release. Recent projects have identified roles for proteins such as dynamin, HAP1, RCAN1 and phosphoinositides in the control of cell signalling, exocytosis, endocytosis and vesicle trafficking.

We are currently testing various mutant mouse models to try and identify novel genes/proteins in the regulation of pancreatic function and insulin secretion. We have identified that the RCAN1 protein is a novel regulator of beta cell function and insulin secretion in Type 2 diabetes and are currently trying to understand the mechanisms by which this regulation occurs.

Selected Publications

Martin AM, Young RL, Leong L, Rogers GB, Spencer NJ, Jessup CF, Keating DJ (2017) The diverse metabolic roles of peripheral serotonin. Endocrinology. [Epub ahead of print]

 

Martin AM, Lumsden AL, Young RL, Jessup CF, Spencer NJ, Keating DJ (2017) The nutrient-sensing repertoires of mouse enterochromaffin cells differ between duodenum and colon. Neurogastroenterol Motil, 29(6)

 

Martin AM, Lumsden AL, Young RL, Jessup CF, Spencer NJ, Keating DJ (2017) Regional differences in nutrient-induced secretion of gut serotonin. Physiol Rep, 5(6):e13199

 

Peiris H, Duffield MD, Fadista J, Jessup CF, Kashmir V, Genders AJ, McGee SL, Martin AM, Saiedi M, Morton N, Carter R, Cousin MA, Kokotos AC, Oskolkov N, Volkov P, Hough TA, Fisher EM, Tybulewicz VL, Busciglio J, Coskun PE, Becker A, Belichenko PV, Mobley WC, Ryan MT, Chan JY, Laybutt DR, Coates PT, Yang S, Ling C, Groop L, Pritchard MA, Keating DJ (2016) A Syntenic Cross Species Aneuploidy Genetic Screen Links RCAN1 Expression to β-Cell Mitochondrial Dysfunction in Type 2 Diabetes. PLoS Genet, 12(5):e1006033

 

Rogers GB, Keating DJ, Young RL, Wong ML, Licinio J, Wesselingh S (2016) From gut dysbiosis to altered brain function and mental illness: mechanisms and pathways. Molecular Psychiatry, 21(6):738-48

 

Lumsden AL, Young RL, Pezos N, Keating DJ (2016) Huntingtin-associated protein 1: Eutherian adaptation from a TRAK-like protein, conserved gene promoter elements, and localization in the human intestine. BMC Evolutionary Biology, 16(1):214

 

Mackenzie KD, Lumsden AL, Guo F, Duffield MD, Chataway T, Lim Y, Zhou XF, Keating DJ (2016) Huntingtin-associated protein-1 is a synapsin I-binding protein regulating synaptic vesicle exocytosis and synapsin I trafficking. Journal of Neurochemistry, 138(5):710-21

 

Raghupathi R, Jessup CF, Lumsden AL, Keating DJ (2016) Fusion Pore Size Limits 5-HT Release From Single Enterochromaffin Cell Vesicles. Journal of Cell Physiology, 231(7):1593-600

 

Meunier FA, Keating DJ (2016) The 18th International Symposia on Chromaffin Cell Biology. Journal of Neurochemistry, 137(6):847-8

 

Thorn P, Zorec R, Rettig J, Keating DJ (2016) Exocytosis in non-neuronal cells. Journal of Neurochemistry, 137(6):849-59

 

Spencer NJ, Keating DJ (2016) Is There a Role for Endogenous 5-HT in Gastrointestinal Motility? How Recent Studies Have Changed Our Understanding. Advances in Experimental Medicine and Biology, 891:113-22

 

Han YC, Lim Y, Duffieldl MD, Li H, Liu J, Abdul Manaph NP, Yang M, Keating DJ, Zhou XF (2016) Direct Reprogramming of Mouse Fibroblasts to Neural Stem Cells by Small Molecules. Stem Cells International, 2016:4304916

 

McCormack A, Chegeni N, Chegini F, Colella A, Power J, Keating D, Chataway T (2016) Purification of α-synuclein containing inclusions from human post mortem brain tissue. Journal of Neuroscience Methods, 266:141-150

 

Young RL, Lumsden AL, Keating DJ (2015) Gut Serotonin Is a Regulator of Obesity and Metabolism. Gastroenterology, 149(1):253-5

 

Jackson J, Papadopulos A, Meunier FA, McCluskey A, Robinson PJ, Keating DJ (2015) Small molecules demonstrate the role of dynamin as a bi-directional regulator of the exocytosis fusion pore and vesicle release. Molecular Psychiatry, 20(7):810-9

 

Papadopulos A, Gomez GA, Martin S, Keating DJ, Jackson J, Gormal RS, Yap AS & Meunier FA (2015) Activity driven relaxation of the cortical acto-myosin II network synchronizes Munc18-1-dependent neurosecretory vesicle docking. Nature Communications, 6:6297

 

Kumar R, Corbett MA, Smith NJC, Jolly LA, Tan C, Keating DJ, Duffield MD, Utsumi T, Moriya K, Smith KR, Hoischen A, Abbott K, Harbord MG, Compton AG, Woenig JA, Arts P, Kwint M, Wieskamp N, Gijsen S, Veltman JA, Bahlo M, Gleeson JG, Haan E and Gecz J (2015) Homozygous mutation of STXBP5L explains an autosomal recessive infantile-onset neurodegenerative disorder. Human Molecular Genetics, 4(7):2000-10

 

Mackenzie KD, Duffield MD, Peiris H, Phillips L, Zanin MP, Teo EH, Zhou X-F and Keating DJ (2014) Huntingtin-associated protein 1 regulates exocytosis, vesicle docking, readily releasable pool size and fusion pore stability in mouse chromaffin cells. Journal of Physiology, 592(7):1505-18

 

Raghupathi R, Duffield MD, Zelkas L, Meedeniya A, Brookes SJH, Sia TC, Wattchow DA, Spencer NJ & Keating DJ (2013) Identification of unique release kinetics of serotonin from guinea-pig and human enterochromaffin cells. Journal of Physiology, 591(Pt 23):5959-75

 

Zanin MP, Mackenzie KD, Peiris H, Pritchard MA, Keating DJ (2013) RCAN1 regulates vesicle recycling and quantal release kinetics via effects on calcineurin activity. Journal of Neurochemistry, 124(3):290-9

 

Peiris H, Raghupathi R, Jessup CF, Zanin MP, Mohanasundaram D, Mackenzie KD, Chataway T, Clarke JN, Brealey J, Coates PT, Pritchard MA, Keating DJ (2012) Increased expression of the glucose-responsive gene, RCAN1, causes hypoinsulinemia, β-cell dysfunction, and diabetes. Endocrinology, 153(11):5212-21

 

Zanin MP, Phillips L, Mackenzie KD, Keating DJ (2011) Aging differentially affects multiple aspects of vesicle fusion kinetics. PLoS One, 6(11):e27820

 

Wen PJ, Osborne SL, Zanin M, Low PC, Wang HT, Schoenwaelder SM, Jackson SP, Wedlich-Söldner R, Vanhaesebroeck B, Keating DJ, Meunier FA (2011) Phosphatidylinositol- (4,5)bisphosphate coordinates actin-mediated mobilization and translocation of secretory vesicles to the plasma membrane of chromaffin cells. Nature Communications, 2:491

 

Jentsch TJ, Maritzen T, Keating DJ and Thevenod F (2010) ClC-3 – a granular anion transporter involved in insulin secretion? Cell Metabolism, 12(4):307-8

 

Keating DJ and Spencer NJ (2010) Real time recordings of 5-HT release from enterochromaffin (EC) cells reveals their role in the generation and propagation of colonic migrating motor complexes. Gastroenterology, 138:659-70

 

Pfeffer, C, Stein, V, Keating DJ, Maier H, Rinke I, Rudhard Y, Hentschke M, Rune G, Jentsch TJ, Hubner CA (2009) NKCC1-Dependent GABAergic Excitation Drives Synaptic Network Maturation During Early Hippocampal Development. Journal of Neuroscience, 29:3419-30

 

Maritzen T, Keating DJ, Neagoe I, Zdebik AA, Jentsch TJ (2008) Role of the vesicular chloride transporter ClC-3 in neuroendocrine tissue. Journal of Neuroscience, 28:10587-98

 

Yu Y, Chu P, Bowser DN, Keating DJ, Harper I, Tkalcevic J, Finkelstein DI, Pritchard MA (2008) Mice deficient for the Down syndrome-related gene Itsn1 exhibit vesicle trafficking abnormalities. Human Molecular Genetics, 17:3281-90

 

Keating DJ, Dubach D, Zanin MP, Yu Y, Martin K, Zhao YF, Chen C, Porta S, Arbonés ML, Mittaz L, Pritchard MA (2008) DSCR1/RCAN1 regulates vesicle exocytosis and fusion pore kinetics: implications for Down syndrome and Alzheimer's disease. Human Molecular Genetics, 17:1020-30

 

Boettger T, Rust MB, Maier H, Seidenbecher T, Schweizer M, Keating DJ, Faulhaber J, Ehmke H, Pfeffer C, Scheel O, Lemcke B, Horst J, Leuwer R, Pape H-C, Völkl H, Hübner CA, Jentsch TJ (2003) Loss of K-Cl co-transporter KCC3 causes deafness, neurodegeneration and reduced seizure threshold. EMBO Journal, 22: 5422-5434

 


Investigator

  • Damien Keating, PhD, Professor, NHMRC Career Development Fellow (Level 2)

Support Staff

  • Amanda Lumsden, PhD, Research Associate

Students

  • Minh-Son To, combined BMBS/PhD Student

  • Alyce Martin, PhD Student

  • Emily Sun, PhD Student

  • Helen Dockrell, PhD Student

  • Pauline Yap, Masters Student

    Julia Demura, Placement Student


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