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Byung-Chang Suh

Bio: Byung-Chang Suh is an academic researcher from Daegu Gyeongbuk Institute of Science and Technology. The author has contributed to research in topics: Phospholipase C & Phosphatidylinositol. The author has an hindex of 26, co-authored 73 publications receiving 3965 citations. Previous affiliations of Byung-Chang Suh include University of Washington & Pohang University of Science and Technology.


Papers
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Journal ArticleDOI
TL;DR: This review discusses the dependence of ion channels on phosphoinositides and considers possible mechanisms by which PIP2 and analogues regulate ion channel activity.
Abstract: Phosphatidylinositol 4,5-bisphosphate (PIP2) is a minority phospholipid of the inner leaflet of plasma membranes. Many plasma membrane ion channels and ion transporters require PIP2 to function and can be turned off by signaling pathways that deplete PIP2. This review discusses the dependence of ion channels on phosphoinositides and considers possible mechanisms by which PIP2 and analogues regulate ion channel activity.

603 citations

Journal ArticleDOI
01 Dec 2006-Science
TL;DR: To resolve the controversy about messengers regulating KCNQ ion channels during phospholipase C–mediated suppression of current, translocatable enzymes that quickly alter the phosphoinositide composition of the plasma membrane after application of a chemical cue are designed.
Abstract: To resolve the controversy about messengers regulating KCNQ ion channels during phospholipase C–mediated suppression of current, we designed translocatable enzymes that quickly alter the phosphoinositide composition of the plasma membrane after application of a chemical cue. The KCNQ current falls rapidly to zero when phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2 or PI(4,5)P2] is depleted without changing Ca2+, diacylglycerol, or inositol 1,4,5-trisphosphate. Current rises by 30% when PI(4,5)P2 is overproduced and does not change when phosphatidylinositol 3,4,5-trisphosphate is raised. Hence, the depletion of PI(4,5)P2 suffices to suppress current fully, and other second messengers are not needed. Our approach is ideally suited to study biological signaling networks involving membrane phosphoinositides.

476 citations

Journal ArticleDOI
01 Aug 2002-Neuron
TL;DR: It is demonstrated here that intracellular ATP is required for recovery of KCNQ2/KCNQ3 current from muscarinic suppression, with an EC(50) of approximately 0.5 mM.

451 citations

Journal ArticleDOI
TL;DR: Recent work has characterized the regulation of a wide range of ion channels by phosphatidylinositol 4,5-bisphosphate, helping to redefine the role of this lipid in cells and in neurobiology.

440 citations

Journal ArticleDOI
TL;DR: The M1 receptor–mediated activation of PLC and suppression of KCNQ current were stopped by lowering intracellular calcium well below resting levels and were slowed by not allowing intrace cellular calcium to rise in response to PLC activation.
Abstract: We have further tested the hypothesis that receptor-mediated modulation of KCNQ channels involves depletion of phosphatidylinositol 4,5-bisphosphate (PIP2) by phosphoinositide-specific phospholipase C (PLC). We used four parallel assays to characterize the agonist-induced PLC response of cells (tsA or CHO cells) expressing M1 muscarinic receptors: translocation of two fluorescent probes for membrane lipids, release of calcium from intracellular stores, and chemical measurement of acidic lipids. Occupation of M1 receptors activates PLC and consumes cellular PIP2 in less than a minute and also partially depletes mono- and unphosphorylated phosphoinositides. KCNQ current is simultaneously suppressed. Two inhibitors of PLC, U73122 and edelfosine (ET-18-OCH3), can block the muscarinic actions completely, including suppression of KCNQ current. However, U73122 also had many side effects that were attributable to alkylation of various proteins. These were mimicked or occluded by prior reaction with the alkylating agent N-ethylmaleimide and included block of pertussis toxin-sensitive G proteins and effects that resembled a weak activation of PLC or an inhibition of lipid kinases. By our functional criteria, the putative PLC activator m-3M3FBS did stimulate PLC, but with a delay and an irregular time course. It also suppressed KCNQ current. The M1 receptor-mediated activation of PLC and suppression of KCNQ current were stopped by lowering intracellular calcium well below resting levels and were slowed by not allowing intracellular calcium to rise in response to PLC activation. Thus calcium release induced by PLC activation feeds back immediately on PLC, accelerating it during muscarinic stimulation in strong positive feedback. These experiments clarify important properties of receptor-coupled PLC responses and their inhibition in the context of the living cell. In each test, the suppression of KCNQ current closely paralleled the expected fall of PIP2. The results are described by a kinetic model.

287 citations


Cited by
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Book ChapterDOI
TL;DR: In this review particular emphasis is placed on the discrepancy between the concentrations ofadenosine, ADP, and ATP in the purine receptors of UDP and UTP.
Abstract: ### A. Overview Extracellular purines (adenosine, ADP, and ATP) and pyrimidines (UDP and UTP) are important signaling molecules that mediate diverse biological effects via cell-surface receptors termed purine receptors. In this review particular emphasis is placed on the discrepancy between the

4,177 citations

Journal ArticleDOI
12 Oct 2006-Nature
TL;DR: Inositol phospholipids mediate acute responses, but also act as constitutive signals that help define organelle identity, and play a fundamental part in controlling membrane–cytosol interfaces.
Abstract: Inositol phospholipids have long been known to have an important regulatory role in cell physiology. The repertoire of cellular processes known to be directly or indirectly controlled by this class of lipids has now dramatically expanded. Through interactions mediated by their headgroups, which can be reversibly phosphorylated to generate seven species, phosphoinositides play a fundamental part in controlling membrane-cytosol interfaces. These lipids mediate acute responses, but also act as constitutive signals that help define organelle identity. Their functions, besides classical signal transduction at the cell surface, include regulation of membrane traffic, the cytoskeleton, nuclear events and the permeability and transport functions of membranes.

2,528 citations

Journal ArticleDOI
TL;DR: This review is focused on purinergic neurotransmission, i.e., ATP released from nerves as a transmitter or cotransmitter to act as an extracellular signaling molecule on both pre- and postjunctional membranes at neuroeffector junctions and synapses, as well as acting as a trophic factor during development and regeneration.
Abstract: This review is focused on purinergic neurotransmission, i.e., ATP released from nerves as a transmitter or cotransmitter to act as an extracellular signaling molecule on both pre- and postjunctional membranes at neuroeffector junctions and synapses, as well as acting as a trophic factor during development and regeneration. Emphasis is placed on the physiology and pathophysiology of ATP, but extracellular roles of its breakdown product, adenosine, are also considered because of their intimate interactions. The early history of the involvement of ATP in autonomic and skeletal neuromuscular transmission and in activities in the central nervous system and ganglia is reviewed. Brief background information is given about the identification of receptor subtypes for purines and pyrimidines and about ATP storage, release, and ectoenzymatic breakdown. Evidence that ATP is a cotransmitter in most, if not all, peripheral and central neurons is presented, as well as full accounts of neurotransmission and neuromodulation in autonomic and sensory ganglia and in the brain and spinal cord. There is coverage of neuron-glia interactions and of purinergic neuroeffector transmission to nonmuscular cells. To establish the primitive and widespread nature of purinergic neurotransmission, both the ontogeny and phylogeny of purinergic signaling are considered. Finally, the pathophysiology of purinergic neurotransmission in both peripheral and central nervous systems is reviewed, and speculations are made about future developments.

1,482 citations

Journal ArticleDOI
TL;DR: The crystal structure of different Kir channels is opening the way to understanding the structure-function relationships of this simple but diverse ion channel family.
Abstract: Inwardly rectifying K+ (Kir) channels allow K+ to move more easily into rather than out of the cell. They have diverse physiological functions depending on their type and their location. There are ...

1,286 citations