Dr. Puljung received his Ph.D. in 2005 from the University of Chicago, where he studied connexins, protein pores involved in direct cell-to-cell communication. In 2005 he moved to the laboratory of Professor William Zagotta at the University of Washington, where he developed new probes to explore the structure and dynamics of protein molecules in the cell. In 2013, he moved again to the University of Oxford to work with Professor Dame Frances Ashcroft studying the response of ATP-sensitive potassium channels, which regulate insulin secretion and neuronal excitability, to changes in metabolism. Dr. Puljung continues to develop and apply new methods to probe protein structure and function. His time spent conducting tutorials at Oxford has placed his teaching emphasis on not only understanding the facts of science, but its process, conduct, and ethics. He believes that learning how to write for a scientific audience is a crucial part of any scientific training.

USING FLUORESCENCE SPECTROSCOPY TO PROBE ION CHANNEL DYNAMICS IN A CELLULAR ENVIRONMENT.

Ion channels are specialized proteins that turn ordinary ionic gradients across the cell membrane into the electrical signals that shape nerve impulses, drive heart beats, underly muscle contractions, and enable sensory perception. When channels are open, ions flow freely through them, generating electrical currents. In the Puljunglab, we use a combination of electrophysiological, biochemical, and spectroscopic techniques to probe the dynamic structural changes that govern ion channel function. Our current interest is in understanding ion channels that are activated or inhibited by the binding of nucleotides like ATP. Such channels regulate excitability in neurons and are implicated in many diseases from neuropathic pain to epilepsy. In particular, we are interested in developing novel ways to measure nucleotide binding to channels in a cellular environment, exploiting these methods to quantify the energetic effects exerted by nucleotides, and delineating the conformational changes induced by nucleotide binding that affect whether the channels are open or closed. We hope that the insights we gain into the working life of these molecular machines will increase our understanding of their physiological function and guide novel therapies for the diseases associated with their dysfunction.

curriculum vitae

• Usher SG, Ashcroft FM, and Puljung MC. (2020) Nucleotide inhibition of the pancreatic ATP-sensitive K⁺ channel explored with patch-clamp fluorometry. eLife. 9:e52775. doi: 10.7554/eLife.52775.
• Puljung M, Vedovato N, Usher S, and Ashcroft F. (2019) Activation mechanism of ATP-sensitive K⁺ channels explored with real-time nucleotide binding. eLife. 8. pii: e41103. doi: 10.7554/eLife.41103. 
• Puljung MC. (2018) Cryo-electron microscopy structures and progress toward a dynamic understanding of K_ATP channels. J Gen Physiol. 150:653-669. review
• Vedovato, N, Ashcroft FM, and Puljung MC. (2015) The nucleotide-binding sites of SUR1: a mechanistic model. Biophys J. 109:2452-60. review
• Puljung MC*, DeBerg HA*, Zagotta WN, and Stoll S. (2014) Double electron-electron resonance reveals cAMP-induced conformational change in HCN channels. Proc Natl Acad Sci USA. 111:9816-21. *These authors contributed equally to this work.
• Puljung MC and Zagotta WN. (2013) A secondary structural transition in the C helix promotes gating of cyclic nucleotide-regulated ion channels. J Biol Chem. 288:1294-56.
• Puljung MC and Zagotta WN. (2011) Labeling of specific cysteines in proteins using reversible metal protection. Biophys J. 100:2513-2521.
• Taraska JW*, Puljung MC*, and Zagotta WN. (2009) Short-distance probes for protein backbone structure based on energy transfer between bimane and transition metal ions. Proc Natl Acad Sci USA. 106:16227-32. *These authors contributed equally to this work.
• Taraska JW, Puljung MC, Olivier NB, Flynn GE, and Zagotta WN. (2009) Mapping the structure and conformational movements of proteins with transition metal ion FRET. Nat Methods. 6:532-7. 
• Puljung MC, Berthoud VM, Beyer EC, and Hanck DA. (2004) Polyvalent cations constitute the voltage gating particle in human connexin37 hemichannels. J Gen Physiol. 124:587-603.