Dejian Ren, Ph. D. Assistant Professor of Biology Ph.D., SUNY at Buffalo, 1997 204H Carolyn Lynch Laboratory Department of Biology University of Pennsylvania Philadelphia, PA 19104 USA V +1 215 898.9271 F +1 215 898.8780 E dren@sas.upenn.edu

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research : publications : education

 

neuronal excitability, neurobiology, rhythmic behavior, ion channels, calcium signaling, mammalian fertilization Cellular excitability influences essentially every aspect of life, from fertilization to breathing and heart beating. The major interests of the lab concern cellular excitability and the regulation by ion channels and calcium signaling. A recent focus is to study the molecular mechanism of neuronal excitability control by extracelular ions (with emphasis on Ca2+ and Na+) and peptide neurotransmitters. Significant changes in extracellular Ca2+ concentrations ([Ca2+]e) can happen in certain brain areas during physiological and pathological conditions such as seizures and brain ischemia. Unlike Na+ and K+, extracellular Ca2+ generally controls neuronal excitability in a “negative” manner: decrease in [Ca2+]e normally excites neurons and increase in [Ca2+]e suppresses neurons. We are interested in understanding at the molecular level how neurons sense the [Ca2+]e changes, how the information is transmitted to the intracellular second messenger system, and how neuronal circuit function is affected. Numerous neuropeptides are used by the nervous systems as chemical signals to regulate physiological processes such as feeding, rewarding, pain sensation, arousal and wakefulness. We are interested in how several neuropeptides influence the electrical properties of individual neurons in various brain regions and spinal cord. Another area of research in the lab concerns rhythm generation. All animals display long-period rhythmic behaviors such as circadian rhythm (~ 24 hours), as well as ones with shorter periods such as locomotion, heart beating, and breathing (milliseconds to seconds). We are interested in the molecular mechanisms underlying the generation and modulation of the “short-period” rhythms. We use an integrative approach to study the physiological problems. At the molecular level, we use molecular biology, protein chemistry and bioinformatics to clone and purify channel proteins and their associated partners. We use electrophysiology methods to record the electrical activities from a single molecule (single channel recording), a whole cell, or a nerve bundle. At the cellular level, we use immunochemstry to determine protein localization and fluorescence microcopy to image Ca2+ dynamics inside the cells. At the systems level, we modify the genomes of animals (usually in the mice using homologous recombination in embryonic stem cells) and study the consequences of such modifications on whole animal physiology and behavior.

selected publications Lu, B., Su, Y., Das, S., Xia, J., Liu, J. and Ren, D. (2007) The neuronal NALCN channel contributes resting sodium permeability and is required for normal respiratory rhythm. Cell 129: 371-378. Liu, J., Xia, J., Cho, K-H., Clapham, D.E. and Ren, D. (2007) CatSperBeta: a novel transmembrane protein in the CATSPER channel complex. J. Biol. Chem. 282: 18945-18952 (in press). Yue, L.*, Navarro, B., Ren, D., Ramos, A. and Clapham, D.E. (2002) The cation selectivity filter of the bacterial sodium channel, NaChBac. J. Gen. Physiol. 120: 845-853. Ren, D., Navarro, B., Xu, H., Yue, L., Shi, Q. and Clapham, D.E. (2001) A prokaryotic voltage-gated sodium channel. Science 294: 2372-2375. Ren, D., Navarro, B., Perez, G., Jackson, A.C., Hsu, S., Shi, Q., Tilly, J.L. and Clapham, D.E. (2001) A sperm ion channel required for sperm motility and male fertility. Nature 413:603-609.

education

Postdoctoral Fellow, HHMI, Children’s Hospital (Boston), Harvard Medical School

Ph.D., Physiology and Biophysics, SUNY at Buffalo

M.S., Underwater Acoustics, Institute of Acoustics, Chinese Academy of Sciences

B.S., Electrical Engineering, Sichuan University, China