Molecular dissection of HCl secretion in gastric parietal cells using streptolysin O permeabilization.
Histamine-stimulated gastric acid secretion involves a transient elevation of intracellular Ca(2+) and the cyclic adenosine monophosphate (cAMP)-dependent protein kinase A (PKA) cascade through phosphorylation, the actions of which ultimately result in the fusion of vesicles containing H,K-ATPase (adenosine triphosphatase) to the apical plasma membrane of parietal cells. To dissect the signaling events underlying gastric acid secretion, we have developed a permeabilized gastric gland model using streptolysin O (SLO). The advantage of this model is its ability to retain cytosolic components that are required for the secretory machinery while granting accessibility for the introduction of macromolecules into the cytoplasm. Our studies showed that acid secretion in SLO-permeabilized glands is a cAMP-dependent process and involves the recruitment of H,K-ATPase-rich tubulovesicles into the apical plasma membrane as judged by biochemical assays. These studies established a functional permeabilized gland model in which the resting-to-secreting transition can be triggered by second messengers, while the manipulation of the cytoplasmic environment can be achieved with ease.
Ding
Xia
X
Department of Physiology, Morehouse School of Medicine, Atlanta, GA, USA.
Wu
Fang
F
Guo
Zhen
Z
Yao
Xuebiao
X
D000255:Adenosine Triphosphate / Q000378:metabolism; D000632:Aminopyrine / Q000378:metabolism; D000818:Animals; D001426:Bacterial Proteins / Q000494:pharmacology; D001681:Biological Assay / Q000379:methods*; D002250:Carbon Radioisotopes; D002458:Cell Fractionation; D002463:Cell Membrane Permeability / Q000187:drug effects*; D000242:Cyclic AMP / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005744:Gastric Acid / Q000378:metabolism*; D017506:H(+)-K(+)-Exchanging ATPase / Q000378:metabolism*; D008561:Membrane Fusion; D010295:Parietal Cells, Gastric / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D011189:Potassium Chloride / Q000378:metabolism; D011817:Rabbits; D015398:Signal Transduction / Q000187:drug effects*; D013301:Streptolysins / Q000494:pharmacology*; D013347:Subcellular Fractions / Q000187:drug effects / Q000378:metabolism; D022161:Transport Vesicles / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*
D001426:Bacterial Proteins; D002250:Carbon Radioisotopes; D013301:Streptolysins; C025964:streptolysin O; D000632:Aminopyrine; D011189:Potassium Chloride; D000255:Adenosine Triphosphate; D000242:Cyclic AMP; D017506:H(+)-K(+)-Exchanging ATPase