My lab studies the protein-protein interactions that underpin signal transduction. Much of our work is focused on understanding the molecular mechanisms by which protein kinases and their relatives, pseudokinases, regulate cell signalling.
Long considered the poor cousins of conventional protein kinases owing to their lack of catalytic activity, pseudokinases have emerged over the past decade as crucial components of signalling pathways across the kingdoms of life. To date there have been few detailed studies of members of the mammalian ‘pseudokinome’, but already it is evident that this protein family exhibits functional diversity consistent with their diverse evolutionary origins.
My lab has focused on the pseudokinase, MLKL, the most terminal (known) effector in the necroptosis cell death pathway. Detailed knowledge of MLKL activation, regulation and downstream activity has set the scene for therapeutic targeting of MLKL. This work provides a template for developing a detailed understanding of how the remaining ~50 uncharacterised pseudokinases modulate cell signalling.
New Zealand, University of Canterbury, BSc (Hons), 1999
Australia, Australian National University, PhD, 2003
Monash Institute of Pharmaceutical Sciences
2017-2019, Project Grant (x2), National Health and Medical Research Council
2017-2019, FSHD Global Therapeutic Tender (Blewitt, Murphy, Burns)
2016-2019, Project Grant (Blewitt, Murphy, Czabotar, Ritchie), National Health and Medical Research Council
2015-2017, Grant-in-aid (Murphy, Alvarez-Diaz, Ernst), Cancer Council Victoria
2014-2016, Project Grant (x2) National Health and Medical Research Council
Meng Y, Davies KA, Fitzgibbon C, Young SN, Garnish SE, Horne CR, Luo C, Garnier JM, Liang LY, Cowan AD, Samson AL, Lessene G, Sandow JJ, Czabotar PE, Murphy JM. Human RIPK3 maintains MLKL in an inactive conformation prior to cell death by necroptosis. Nat Commun. 2021 Nov 22;12(1):6783. doi: 10.1038/s41467-021-27032-x. PMID: 34811356
Garnish SE, Meng Y, Koide A, Sandow JJ, Denbaum E, Jacobsen AV, Yeung W, Samson AL, Horne CR, Fitzgibbon C, Young SN, Smith PPC, Webb AI, Petrie EJ, Hildebrand JM, Kannan N, Czabotar PE, Koide S, Murphy JM. Conformational interconversion of MLKL and disengagement from RIPK3 precede cell death by necroptosis. Nat Commun. 2021 Apr 13;12(1):2211. doi: 10.1038/s41467-021-22400-z. PMID: 33850121
Samson AL, Zhang Y, Geoghegan ND, Gavin XJ, Davies KA, Mlodzianoski MJ, Whitehead LW, Frank D, Garnish SE, Fitzgibbon C, Hempel A, Young SN, Jacobsen AV, Cawthorne W, Petrie EJ, Faux MC, Shield-Artin K, Lalaoui N, Hildebrand JM, Silke J, Rogers KL, Lessene G, Hawkins ED, Murphy JM. MLKL trafficking and accumulation at the plasma membrane control the kinetics and threshold for necroptosis. Nat Commun. 2020 Jun 19;11(1):3151. doi: 10.1038/s41467-020-16887-1. PMID: 32561730
Samson AL, Fitzgibbon C, Patel KM, Hildebrand JM, Whitehead LW, Rimes JS, Jacobsen AV, Horne CR, Gavin XJ, Young SN, Rogers KL, Hawkins ED, Murphy JM. A toolbox for imaging RIPK1, RIPK3, and MLKL in mouse and human cells. Cell Death Differ. 2021 Jul;28(7):2126-2144. doi: 10.1038/s41418-021-00742-x. Epub 2021 Feb 15. PMID: 33589776
Petrie EJ, Sandow JJ, Jacobsen AV, Smith BJ, Griffin MDW, Lucet IS, Dai W, Young SN, Tanzer MC, Wardak A, Liang LY, Cowan AD, Hildebrand JM, Kersten WJA, Lessene G, Silke J, Czabotar PE, Webb AI, Murphy JM. Conformational switching of the pseudokinase domain promotes human MLKL tetramerization and cell death by necroptosis. Nat Commun. 2018 Jun 21;9(1):2422. doi: 10.1038/s41467-018-04714-7. PMID: 29930286
Murphy JM*, Czabotar PE*, Hildebrand JM*, Lucet IS, Zhang JG, Alvarez-Diaz S, Lewis R, Lalaoui N, Metcalf D, Webb AI, Young SN, Varghese LN, Tannahill GM, Hatchell EC, Majewski IJ, Okamoto T, Dobson RCJ, Hilton DJ, Babon JJ, Nicola NA, Strasser A, Silke J, Alexander WS. The pseudokinase MLKL mediates necroptosis via a molecular switch mechanism. Immunity. 2013 19 September 2013;39(3):443-53. PMID: 24012422
Hildebrand JM, Tanzer MC, Lucet IS, Young SN, Spall SK, Sharma P, Pierotti C, Garnier JM, Dobson RC, Webb AI, Tripaydonis A, Babon JJ, Mulcair MD, Scanlon MJ, Alexander WS, Wilks AF, Czabotar PE, Lessene G, Murphy JM*, Silke J*. Activation of the pseudokinase MLKL unleashes the four-helix bundle domain to induce membrane localization and necroptotic cell death. Proc Natl Acad Sci U S A. 2014 Oct 21;111(42):15072-7. PMID: 25288762
Babon JJ*, Kershaw NJ*, Murphy JM*, Varghese LN, Laktyushin A, Young SN, Lucet IS, Norton RS, Nicola NA. Suppression of cytokine signaling by SOCS3: characterization of the mode of inhibition and the basis of its specificity. Immunity. 2012 Feb 24;36(2):239-50. PMID: 22342841
Murphy JM, Korzhnev DM, Ceccarelli DF, Briant DJ, Zarrine-Afsar A, Sicheri F, Kay LE, Pawson T. Conformational instability of the MARK3 UBA domain compromises ubiquitin recognition and promotes interaction with the adjacent kinase domain. Proc Natl Acad Sci U S A. 2007 Sep 4;104(36):14336-41. PMID: 17726107
Murphy JM*, Zhang Q, Young SN, Reese ML, Bailey FP, Eyers PA, Ungureanu D, Hammaren H, Silvennoinen O, Varghese LN, Chen K, Tripaydonis A, Jura N, Fukuda K, Qin J, Nimchuk Z, Mudgett MB, Elowe S, Gee CL, Liu L, Daly RJ, Manning G, Babon JJ, Lucet IS*. A robust methodology to subclassify pseudokinases based on their nucleotide-binding properties. Biochem J. 2014 Jan 15;457(2):323-34. PMID: 24107129.
The pseudokinase, MLKL, is the terminal effector in the necroptosis cell death pathway. Our structural studies and development of MLKL-deficient laboratory models have enabled us to greatly advance mechanistic knowledge of this protein. Our ongoing work is directed toward understanding how MLKL kills cells following its activation by the upstream protein kinase, RIPK3, and the role of this pathway in causing inflammatory diseases and cancer. These studies are highly collaborative and draw upon in vivo biology, structural biology, molecular and cellular biology, biochemistry, chemical biology and proteomics approaches.
We have identified allostery, molecular switch, scaffolding and competition functions for pseudokinases from detailed structural and functional characterization. Many pseudokinases remain understudied and are considered members of the “dark kinome”. Ongoing work seeks to define the biological functions of these proteins, how they misfunction in disease, and establish their candidacy as drug targets to counter human diseases, especially inflammatory and proliferative diseases. Our work is highly collaborative, with integration of in vivo biology, structural biology, molecular and cellular biology, biochemistry, chemical biology and proteomics to dissect their functions.
Smchd1 is a poorly understood protein comprising an N-terminal ATPase and C-terminal hinge domain. Our recent studies have sought to understand the biological functions (in collaboration with Prof Marnie Blewitt) and structures (in collaboration with Prof Peter Czabotar) of the component domains with a view to understanding its pleiotropic roles as a tumour suppressor, in X chromosome inactivation and gene imprinting.