Surfactant phospholipid secretion from rat alveolar type ii cells:
possible role of protein kinase c isozymes.
Linke, Michael J., Fannie M. Burton, Dana T. Fiedeldey, Ward R. Rice.
Children's Hospital Medical Center, Division of Pulmonary Biology,
Cincinnati, OH
APStracts 3:0172L, 1996.
Protein kinase C (PKC) plays an integral role in control of many Type
II cell functions, including regulation of surfactant phospholipid
secretion. To determine which isozymes of PKC may regulate Type II
cell functions, we identified those PKC isozymes activated in Type II
cells in association with surfactant phospholipid secretion following
phorbol ester treatment. Transcripts encoding PKC -a, -b, -d, -e, -h,
and -z were detected in Type II cells by rtPCR, while PKC -a, -b, -d,
-h, and -z were detected in Type II cells by immunoblotting. PKC -a
and -b were only present in the cytosol in unstimulated Type II cells
while PKC isozymes [delta], h, and z were found in cytosol and
membrane fractions in unstimulated Type II cells. TPA stimulated
surfactant secretion and activated PKC a, b, d, and h isozymes in a
dose-dependent manner. The inactive analogue 4-a-PDD neither
activated PKC isozymes, nor stimulated surfactant phospholipid
secretion. PKC z was not activated by any of the phorbol esters. PKC
isozymes a, b, d, and h are present in purified Type II epithelial
cells and are activated in a dose-dependent manner in alveolar Type
II cells in association with surfactant phospholipid secretion
following phorbol ester treatment.
Received 2 June 1995; accepted in final form 18 September 1996.
APS Manuscript Number L183-5.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 5 November 1996