Department of Neurobiology,
Pharmacology and Physiology
Committee on Molecular Metabolism
Ph.D., University of California, Los Angeles
Phone: (773) 702-0126
The University of Chicago
Ab 506A, (MC 0926)
5841 South Maryland Avenue
Chicago, Illinois 60637
Related Research Interests:
Deborah Joyce Nelson, Ph.D.
Function of Ion Channels in
Research in the laboratory over the past ten years has
further explored ion channel-mediated signal transduction in
non-excitable cells focusing on regulation via intracellular
protein-protein interactions. Using recent examples of studies
conducted in the laboratory, these interactions can subserve vastly
different cellular functions which may gate or open a channel as in the
case of the G protein coupled K channel (GIRK or Kir 3.X) (1) or the
CaMKII-activated chloride channel (2,3). Protein-protein interactions
may modulate the time a channel spends in the open state as with the
interaction of members of the SNARE protein family with the CFTR
(Cystic Fibrosis Transport Regulator) chloride channel (4-6).
Conversely, a complex of regulatory proteins may play a concerted role
in inhibiting channel open time as is the case with annexin IV and
CaMKII in the regulation of the CaMKII –activated chloride channel
(7,8). And finally, ion channels may be held together in regulatory
networks or membrane rafts via interactions with the actin cytoskeleton
(9). We have used as our target proteins both K and Cl channels and
have studied protein mediated channel regulation in both classes of
proteins recognized as mediators of membrane potential stabilization.
CFTR Chloride Channel
Modulation by Vesicle Trafficking Proteins
Accumulating evidence suggests that many ion channels
reside within a multiprotein complex that contains kinases and other
signaling molecules. CFTRis an example of such a channel. CFTR is
activated by cAMP dependent kinase when two nucleotide binding domains
are bound with ATP. Over the past few years, my laboratory has
collaborated with the laboratory of Dr. Kevin Kirk at the University of
Alabama at Birmingham to explore protein-protein interactions between
CFTR and vesicle trafficking proteins of the class used to control
neurotransmitter release in neuroendocrine cells. We have established
that three of these proteins, namely syntaxin, munc-18 and SNAP 23 all
interact to modulate channel open time. The interaction of syntaxin is
highly specific, recognizing a segment of some 20 amino acids in the
N-terminal domain of CFTR to inhibit channel opening. The binding of
munc-18 and SNAP 23 regulate the affinity of the binding interaction
between syntaxin and CFTR and, thereby, channel open time. We have
established that the interaction is stoichiometric and involves direct
protein-protein interactions rather than changes in protein
trafficking. This paradigm of membrane trafficking proteins, syntaxin
1A, SNAP 23 and munc 18, regulating the activity of the proteins which
are at the cell surface has been subsequently shown for a number of
channel and transport proteins and our studies provided the first
evidence that such a interaction exists and that the interaction is
Chloride Channel Biology
The activation of chloride channels subserves a
multiplicity of cellular functions including membrane potential
stabilization, volume regulation, salt and water balance, and
intracellular vesicle acidification. Recent work in the laboratory has
focused on the cloning, expression, and regulation of one of the most
important of the voltage dependent chloride channels, ClC-3. While
broad expression and physiological importance of ClC-3 has been
established, the mechanism of channel activation has remained elusive.
In a recent study, my laboratory has characterized the activation
pathway for ClC-3 when it is expressed in the plasma membrane and has
shown its gating to be dependent upon phosphorylation by the
multifunctional, calcium/calmodulin dependent kinase, CaMKII. In
earlier studies on the endogenous channel expressed in cell lines
derived from the gastrointestinal system we were able to show that the
channel was regulated by inositol phosphates and the
calcium/phospholipid dependent protein annexin IV (2,7). On-going
studies are directed at the determination of channel oligomeric
structure in the plasma membrane as well as cytoplasmic compartments
and preliminary data suggests that the channel can function in two
oligomeric states dependent upon the site of expression. If this turns
out to be the case, then ClC-3 will be the only channel that is capable
of functional expression in two different oligomeric forms. Recent
studies in the laboratory also demonstrate that regulation of ClC-3
involves a cytoskeletal scaffolding that localizes the activating
kinase in close proximity to its target channel domain.
Secretion and Particle Uptake
The final component of the research agenda within the
laboratory focuses on the regulation of particle uptake and secretion
in the macrophage bactericidal response. Our recent studies have
determined that unlike the neuroendocrine cell, secretion in the
macrophage is highly dependent upon activated G proteins (10). Calcium
plays only a modulatory role, enhancing the gain on secretion
presumably by mobilizing vesicles from a ready reserve pool. This model
for secretion is vastly different from that present in cells of
neuroendocrine origin where secretion is determined in toto by a
calcium dependent mechanism. The ability to selectively mobilize
membrane bound granule/vesicle proteins into the external environment
is central to the role of the macrophage in the inflammatory response.
Surface receptor ligation by invading microorganisms initiates the
immune response via the formation of a plasma membrane bound phagosome.
The content of the phagosome is determined primarily by the contents of
the cytoplasmic granules that discharge into it immediately following
particle ingestion. The cellular fate of the fully mature phagosome, a
subset of the intracellular vesicle population present in the
macrophage, had not been determined until the publication of our recent
study demonstrating quantal release of free radicals which accompanies
phagosomal recycling to plasma membrane sites (11).
Future Investigations and
Studies on-going in the laboratory are directed at the
subcellular localization of the regulatory proteins involved in the
activation of the chloride channel ClC-3. In parallel, we are
continuing our productive collaboration with Dr. Kevin Kirk at the
University of Alabama at Birmingham further exploring protein-protein
interactions in the regulation of CFTR. We have extended our studies to
including a mutational analyis of the binding partners within the SNARE
complex in epithelial cells and CFTR in an attempt to augment the
channel trafficking defect that is present in the disease of cystic
fibrosis. We are also involved in an active collaborative relationship
with Dr. Clive Palfrey here at the University where we are exploring
the involvement of the GTP-ase, dynamin in the regulation of both
particle uptake and phagosomal recycling in the activated macrophage.
Finally, we are exploring the mechanism of channel gating in the G
protein activated K channel K. It is our hypothesis that the C terminal
domains of the multisubunit structure interact to form a binding pocket
stabilizing activation by the heterotrimeric G protein subunits Gbg.
Li, C., Dandridge, K.S., Di, A., Marrs, K.L., Harris, E.L., Koushik, R., Jackson, J.S., Makarova, N.V., Fugiwara, Y., Farrar, P.L., Nelson, D.J., Tigyi, G.J., and Naren, A.P. 2005 Lysophosphatidic acid inhibition of diarrhea through CFTR-dependent protein interactions. J. Exp. Med. 202:975-986.
Di, A., Brown, M.E., Deriy, L.V., Li, C., Szeto, F.L., Chen, Y., Huang, P., Tong, J., Naren, A.P., Bindokas, V., Palfrey, H.C., and Nelson, D.J. 2006. CFTR regulates phagosome acidification in macrophages and alters bactericidal activity. Nature Cell Biology 8:933-944.
Faculty of 1000 Biology: evaluations for Di A et al Nat Cell Biol 2006 Sep 8 (9):933-44 http://www.f1000biology.com/article/id/1040460/evaluation
News and Views for this paper:
Swanson, J. 2006. CFTR: helping to acidify macrophage lysosomes. Nature Cell Biology 8:908-909.
Burroughs Wellcome Science 5/ Topical Updates 1081 Citation
Wang, X.Q., Deriy, L.V., Foss, S., Huang, P., Lamb, F.S., Kaetzel, M.A., Bindokas, V., Marks, J.D., Nelson, D.J. 2006. ClC3 channels modulate excitatory synaptic transmission in hippocampal neurons. Neuron52: 321-333.
Nature Research Highlights Citation for this paper: Housekeeper has two jobs. Nature 444:4 (2006)
Ganeshan, R., Nowotarski, K., Di, A., Nelson, D.J., and Kirk, K.L. 2007. An N-WASP inhibitor decreases CFTR surface expression and CFTR-mediated chloride currents. Biochimica et Biophysica Acta – Molecular Cell Research1773(2):192-200.
Li, C., Krishnamurthy, P.C., Penmatsa, H., Marrs, K.L., Wang, X.Q., Zaccolo, M., Jalink, K., Li, M., Nelson, D.J., Schuetz, J.D., and Naren, A.P. 2007. Spatiotemporal coupling of cAMP transporter to CFTR chloride channel function in the gut epithelia. Cell 131: 940-951.
Claud, E.C., Lu, J., Wang,,XQ., Abe, M., Petrof , E.O., Sun, J., Nelson, D.J., Marks, J.D., Jilling, T. 2008. Platelet-activating Factor induced chloride channel activation is associated with intracellular acidosis and apoptosis of intestinal epithelial cells. Am J. Physiol. Gastrointest. Liver Physiol. 294:G1191-2000.
Mitchell, J., Wang, X., Zhang, G., Gentzsch, M., Nelson, D.J., and Shears, S.B. 2008. An expanded biological repertoire for Ins(3,4,5,6)P4 through its modulation of ClC-3 function. Current Biology 18(20):1600-5.
Deriy, L.V., Gomez, E.A., Jacobson, D.A., Wang, X.., Hopson, J.A., Liu, X.Y., Zhang, G., Bindokas, V.P., Philipson, L.H., and Nelson,, D.J. 2009. The granular chloride channel ClC-3 is permissive for insulin secretion. Cell Metabolism 10:316-323.
Deriy, L.V., Gomez, E.A., Zhang, G., Beacham, D., Hopson, J.A., Gallan, A.J., Shevchenko, P., Bindokas, V.P., and Nelson, D.J. 2009. Disease causing mutations in the cystic fibrosis transmembrane conductance regulator determine the functional responses of alveolar macrophages. J. Biol. Chem. 284:35926-38.
Mitterreiter, S., Page, R.M., Kamp, F., Hopson, J.A., Winkler, E., Ha, H.-R., Hamid, R., Herms, J., Mayer, T.U., Nelson, D.J., Steiner, H., Stahl, T., Zeitschel, U., Rossner, S., Haass, C., and Lichtenthaler, S.F. 2010. Bepridil and amiodarone simultaneously target the Alzheimer’s disease b- and g-secretase via distinct mechanisms. J. Neuroscience 30:8974-83.
Penmasta, H., Zhang, W., Yarlagadda, S., Li, C., Conoley, V.G., Yue, J., Bahouth, S.W., Buddington, R.K., Zhang, G., Nelson, D.J., Sonecha, M.D., Manganiello, V., Wine, J.J., Naren, A.P. 2010. Compartmentalized cAMP at the plasma membrane clusters PDE3A and CFTR into microdomains. Molecular Biology of the Cell 21:1097-110.
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