The objective of the proposed experiments is to determine the role of glycosylation in the functioning of the Kv1.1 potassium channel. Previous studies by the investigator have indicated an important effect of glycosylation on voltage dependence and kinetics of activation. On the bases of studies involving changes in extracellular calcium, the modulation of function by specific glycosylations were proposed to occur through changes in surface potential and through effects on the voltage sensor. Now the investigator proposes to identify the contributions of individual glycosylation sites on the voltage dependence through continued mutation and expression of Kv1.1 alpha subunits. Functional and biochemical measurements will be used to determine consequences of decreasing the charge of identified sialidations on channel gating and toxin binding. Divalent sensitivity will be taken as a measure of the contributions by surface potential to gating. In complementary studies the functional effects of increasing the channels silidation state on channel gating, voltage dependence and divalent sensitivity will be tested. These experiments form the bases for hypothesizing that channel glycosylation represents an important mechanism of postranslational modulation of ion channel function.

National Institute of Health (NIH)
National Institute of Neurological Disorders and Stroke (NINDS)
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Physiology Study Section (PHY)
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Stewart, Randall
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Fordham University
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Zhu, Jing; Gomez, Barbara; Watanabe, Itaru et al. (2005) Amino acids in the pore region of Kv1 potassium channels dictate cell-surface protein levels: a possible trafficking code in the Kv1 subfamily. Biochem J 388:355-62
Sutachan, Jhon J; Watanabe, Itaru; Zhu, Jing et al. (2005) Effects of Kv1.1 channel glycosylation on C-type inactivation and simulated action potentials. Brain Res 1058:30-43
Watanabe, Itaru; Zhu, Jing; Recio-Pinto, Esperanza et al. (2004) Glycosylation affects the protein stability and cell surface expression of Kv1.4 but Not Kv1.1 potassium channels. A pore region determinant dictates the effect of glycosylation on trafficking. J Biol Chem 279:8879-85
Zhu, Jing; Watanabe, Itaru; Gomez, Barbara et al. (2003) Heteromeric Kv1 potassium channel expression: amino acid determinants involved in processing and trafficking to the cell surface. J Biol Chem 278:25558-67
Castillo, Cecilia; Thornhill, William B; Zhu, Jing et al. (2003) The permeation and activation properties of brain sodium channels change during development. Brain Res Dev Brain Res 144:99-106
Zhu, Jing; Watanabe, Itaru; Poholek, Amanda et al. (2003) Allowed N-glycosylation sites on the Kv1.2 potassium channel S1-S2 linker: implications for linker secondary structure and the glycosylation effect on channel function. Biochem J 375:769-75
Zhu, Jing; Watanabe, Itaru; Gomez, Barbara et al. (2003) Trafficking of Kv1.4 potassium channels: interdependence of a pore region determinant and a cytoplasmic C-terminal VXXSL determinant in regulating cell-surface trafficking. Biochem J 375:761-8
Thornhill, W B; Watanabe, I; Sutachan, J J et al. (2003) Molecular cloning and expression of a Kv1.1-like potassium channel from the electric organ of Electrophorus electricus. J Membr Biol 196:1-8
Watanabe, Itaru; Wang, Hong-Gang; Sutachan, Jhon J et al. (2003) Glycosylation affects rat Kv1.1 potassium channel gating by a combined surface potential and cooperative subunit interaction mechanism. J Physiol 550:51-66
Zhu, L; Wu, X; Wu, M B et al. (2001) Cloning and characterization of G protein-gated inward rectifier K+ channel (GIRK1) isoforms from heart and brain. J Mol Neurosci 16:21-32

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