Cytoskeletal architecture in mouse lung epithelial cells is
regulated by protein kinase c[alpha] and calpain ii .
Dwyer-Nield, Lori D., Anita C. K. Miller, Bonnie W. Neighbors, David
Dinsdale, and Alvin M. Malkinson.
Department of Pharmaceutical Sciences, School of Pharmacy,
University of Colorado Health Sciences Center, 4200 E. 9th Avenue,
Denver, Colorado 80262, Telephone (303) 270-4579, Fax (303) 270
-6281
APStracts 2:0194L, 1995.
Brief exposure to 12-O-tetradecanoyl-13-phorbol acetate (TPA) caused a
uniform population of flattened mouse lung epithelial cells to become
more heterogeneous; some cells rounded-up and others detached to
overlap with flatter cells. Actin stress fiber organization was
disrupted, and F-actin accumulated in lamellopodia. Vinculin
dissociated from the focal adhesion plaques to diffuse throughout the
cytoplasm. Inhibition of protein kinase C (PKC) activity blocked
these effects of TPA. After 8 hours of TPA exposure, actin filaments
reassembled and vinculin again localized to the cell periphery.
Calpain inhibition attenuated the decrease of PKC[alpha] protein and
PKC activity from the membrane fraction, and prevented the
redistribution of cytoskeletal elements. Talin immunostaining was
widespread throughout control cells, but localized to the periphery 8
hours after treatment with TPA or with inhibitors of PKC and calpain.
Both vinculin and talin concentrations increased with prolonged TPA
treatment. PKCz and calpain II were not appreciably affected by TPA
exposure. Translocation of PKC[alpha] to the membrane followed by its
calpain-induced downmodulation is apparently required for the
reversible pattern of cytoskeletal changes caused by TPA.
Received 2 August 1995; accepted in final form 18 October 1995.
APS Manuscript Number L243-5.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 6 November 95