Boston University Department of Biology

Faculty Profiles

Current Research

We use photoreceptors and neurons of the fruit fly, Drosophila melanagaster, as our model system, to address questions about the subcellular organization of signaling proteins and ion channels. In Drosophila photoreceptors, signaling components are localized in a specialized signaling compartment of the cell, the rhabdomere, where phototransduction occurs. In recent years, an interesting twist to this compartmentalized strategy of signaling has emerged: a few of the signaling components, including the Gqa subunit and light-activated TRPL channel, display light-dependent mobilization between the rhabdomere and cell body of the photoreceptor cell. This light-induced subcellular translocation is likely a mechanism for regulating the quantity of a component available for signaling, and has been suggested to contribute to long-term light-adaptation in both vertebrates and invertebrates. Through genetic analyses, live-imaging, electrophysiology, and biochemical manipulations, we investigate the molecular mechanisms underlying Gqa and TRPL transport and their function in light-adaptation.

A second focus of the lab is on the voltage-gated K+ channel, Shal (Kv4). Drosophila Shal K+ channels display both somato-dendritic localization and variable inactivation rates, similar to mammalian Shal channels. They are involved in integrating post-synaptic potentials and inhibiting the back-propagation of action potentials in dendrites, as well as shaping the cardiac action potential. Our recent work has focused on the identification of new protein interactors that regulate either the biophysical properties or dendritic localization of Shal channels. Using Drosophila as our model system enables us to combine a variety of experimental approaches to examine the function of these new interactors in vivo.

Courses Taught

• BI 481/681 Molecular Biology of the Neuron

Selected Publications

• Sanxaridis P, Cronin MA, Waro G, Tsunoda S: Light-Induced Recruitment of INAD-Signaling Complexes to Lipid Rafts in Drosophila Photoreceptors. Molecular and Cellular Neuroscience (2007); 36(1), 36-46.
• Cronin MA, Lieu M-H, Tsunoda S: Two Stages of Light-Dependent TRPL-Channel Translocation in Drosophila Photoreceptors. J Cell Sci. (2006); 119, 2935-2944.
• Cronin MA, Diao F, Tsunoda S: The Light-Dependent Subcellular Translocation of Gq a in Drosophila Photoreceptors is Facilitated by the Photoreceptor-Specific Myosin III, NINAC. J. Cell Sci. (2004); 117, 4797-4806.
• Tsunoda S, Sun Y, Suzuki E, Zuker CS: Independent Assembly and Anchoring Mechanisms of INAD-Signaling Complexes. J Neurosci (2001); 21(1), 150-158.
• Tsunoda S, Sierralta J, Sun Y, Bodner R, Suzuki E, Becker A, Socolich M, Zuker CS: A Multivalent PDZ-Domain Protein Assembles Signalling Complexes in a G-Protein-Coupled Cascade. Nature (1997); 388, 243-249.
• Tsunoda S, Salkoff L: The Major Delayed Rectifier in Both Drosophila Neurons and Muscle is Encoded by Shab. J. Neurosci. (1995); 15(7), 5209-5221.
• Tsunoda S, Salkoff L: Genetic Analysis of Drosophila Neurons: Shal, Shaw, and Shab Encode Most Embryonic Potassium Currents. J. Neurosci. (1995); 15(3), 1741-1754.
• Butler A, Tsunoda S, McCobb D, Wei A, Salkoff L: mSlo, a Complex Mouse Gene Encoding “Maxi” Calcium-Activated Potassium Channels. Science (1993); 261, 221-224.