Effective pulmonary mucociliary clearance is dependent upon the respiratory tract fluid. Ion transport by airway epithelia plays a critical role in controlling volume and composition of the respiratory tract fluid, and thus in controlling mucociliary clearance. The overall aim of this proposal is to characterize the mechanisms of airway epithelial ion transport. There are two specific aims. The first goal is to define the cellular mechanisms of ion transport by tracheal epithelium. To gain an understanding of the mechanisms involved, it is necessary to examine the transport processes at the level of the individual cell membranes. This work will be directed at a definition of the electrochemical driving forces for ion movement across each cell membrane, the ionic permeabilities of the membranes, and the development of kinetic, mechanistic descriptions of the membrane transport processes. This approach requires the use of techniques capable of probing the cell interior and of focusing on ion flows across individual cell membranes. In these studies I will use intracellular microelectrode techniques, an equivalent electrical circuit analysis, intracellular ion-selective microelectrodes, and the measurement of radioisotope fluxes to characterize the individual transport mechanisms.
The second aim of this proposal is to investigate the abnormalities of airway epithelial ion transport in diseases associated with abnormal mucociliary clearance. Specifically, I will focus on the abnormalities of airway ion transport associated with cystic fibrosis and the inhalaton of cigarette smoke.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL029851-03
Application #
3340920
Study Section
Physiology Study Section (PHY)
Project Start
1983-01-01
Project End
1986-06-30
Budget Start
1985-01-01
Budget End
1986-06-30
Support Year
3
Fiscal Year
1985
Total Cost
Indirect Cost
Name
University of Iowa
Department
Type
Schools of Medicine
DUNS #
041294109
City
Iowa City
State
IA
Country
United States
Zip Code
52242
Randak, Christoph O; Welsh, Michael J (2005) ADP inhibits function of the ABC transporter cystic fibrosis transmembrane conductance regulator via its adenylate kinase activity. Proc Natl Acad Sci U S A 102:2216-20
Randak, Christoph O; Welsh, Michael J (2005) Adenylate kinase activity in ABC transporters. J Biol Chem 280:34385-8
Berger, Allan L; Randak, Christoph O; Ostedgaard, Lynda S et al. (2005) Curcumin stimulates cystic fibrosis transmembrane conductance regulator Cl- channel activity. J Biol Chem 280:5221-6
Berger, Allan L; Ikuma, Mutsuhiro; Welsh, Michael J (2005) Normal gating of CFTR requires ATP binding to both nucleotide-binding domains and hydrolysis at the second nucleotide-binding domain. Proc Natl Acad Sci U S A 102:455-60
Randak, Christoph; Welsh, Michael J (2003) An intrinsic adenylate kinase activity regulates gating of the ABC transporter CFTR. Cell 115:837-50
Liu, Lei; Leonard, A Soren; Motto, David G et al. (2003) Contribution of Drosophila DEG/ENaC genes to salt taste. Neuron 39:133-46
Berger, Allan L; Ikuma, Mutsuhiro; Hunt, John F et al. (2002) Mutations that change the position of the putative gamma-phosphate linker in the nucleotide binding domains of CFTR alter channel gating. J Biol Chem 277:2125-31
Hennager, D J; Ikuma, M; Hoshi, T et al. (2001) A conditional probability analysis of cystic fibrosis transmembrane conductance regulator gating indicates that ATP has multiple effects during the gating cycle. Proc Natl Acad Sci U S A 98:3594-9
Cotten, J F; Welsh, M J (1999) Cystic fibrosis-associated mutations at arginine 347 alter the pore architecture of CFTR. Evidence for disruption of a salt bridge. J Biol Chem 274:5429-35
Hall, R A; Ostedgaard, L S; Premont, R T et al. (1998) A C-terminal motif found in the beta2-adrenergic receptor, P2Y1 receptor and cystic fibrosis transmembrane conductance regulator determines binding to the Na+/H+ exchanger regulatory factor family of PDZ proteins. Proc Natl Acad Sci U S A 95:8496-501

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