Proteome of the porosome complex in human airway epithelia: interaction with the cystic fibrosis transmembrane conductance regulator (CFTR).
The surface of the airways is coated with a thin film of mucus composed primarily of mucin, which is under continuous motion via ciliary action. Mucin not only serves to lubricate the airways epithelia, but also functions as a trap for foreign particles and pathogens, thereby assisting in keeping the airways clean and free of particulate matter and infections. Altered mucin secretion especially increased mucin viscosity, results in mucin stagnation due to the inability of the cilia to propel them, leading to infections and diseases such as cystic fibrosis (CF). Since porosomes have been demonstrated to be the secretory portals at the cell plasma membrane in cells, their presence, structure, and composition in the mucin-secreting human airway epithelial cell line Calu-3 expressing CF transmembrane receptor (CFTR), were investigated. Atomic force microscopy (AFM) of Calu-3 cells demonstrates the presence of approximately 100nm in diameter porosome openings at the plasma membrane surface. Electron microscopy confirms the AFM results, and tandem mass spectrometry and immunoanalysis performed on isolated Calu-3 porosomes, reveal the association of CFTR with the porosome complex. These new findings will facilitate understanding of CFTR-porosome interactions influencing mucous secretion, and provide critical insights into the etiology of CF disease.


CONCLUSIONS
In the present study, the porosome proteome in human airway epithelia has been determined. The interaction between the cystic fibrosis transmembrane conductance regulator (CFTR) and the porosome complex in the human airway epithelia is further demonstrated. The possible regulation by CFTR on the quality of mucus secretion via the porosome complex at the cell plasma membrane is hypothesized. These new findings will facilitate understanding of CFTR-porosome interactions influencing mucous secretion, and provide critical insights into the etiology of CF disease.
Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA.
Xia
X
Hou
Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA.
Kenneth T
KT
Lewis
Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA.
Qingtian
Q
Wu
Department of Chemical Engineering & Materials Science, College of Engineering, Wayne State University, MI 48202, USA.
Sunxi
S
Wang
Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA.
Xuequn
X
Chen
Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA.
Amanda
A
Flack
Department of Chemical Engineering & Materials Science, College of Engineering, Wayne State University, MI 48202, USA.
Guangzhao
G
Mao
Department of Pathology, Microscopy Imaging Center, University of Vermont College of Medicine, Burlington, VT 05405, USA.
Douglas J
DJ
Taatjes
Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA.
Fei
F
Sun
Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA; Department of Chemical Engineering & Materials Science, College of Engineering, Wayne State University, MI 48202, USA. Electronic address: bjena@med.wayne.edu.
Bhanu P
BP
Jena
D045744:Cell Line, Tumor; D021961:Cell Membrane Structures / Q000378:metabolism* / Q000648:ultrastructure; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D018625:Microscopy, Atomic Force; D009093:Mucus / Q000378:metabolism; D020543:Proteome / Q000378:metabolism*; D020545:Respiratory Mucosa / Q000378:metabolism* / Q000648:ultrastructure
C505032:CFTR protein, human; D020543:Proteome; D019005:Cystic Fibrosis Transmembrane Conductance Regulator
Human airway epithelia porosome proteome; Mucus secretion; Porosome–CFTR interaction; Tandem mass spectrometry