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HSP27 expression regulates CCK-induced changes of the actin cytoskeleton in CHO-CCK-A cells
Departments of 1 Physiology, 3 Internal Medicine, and 2 Anatomy and Cell Biology, University of Michigan, Ann Arbor, Michigan 48109-0622 We investigated how heat shock protein 27 (HSP27) and its phosphorylation are involved in the action of cholecystokinin (CCK) on the actin cytoskeleton by genet...
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| Published in: | American Journal of Physiology: Cell Physiology 1999-12, Vol.277 (6), p.C1032-C1043 |
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| Main Authors: | , , , , |
| Format: | Article |
| Language: | English |
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| Online Access: | Get full text |
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| Summary: | Departments of 1 Physiology,
3 Internal Medicine, and
2 Anatomy and Cell Biology, University of
Michigan, Ann Arbor, Michigan 48109-0622
We investigated how heat shock protein 27 (HSP27)
and its phosphorylation are involved in the action of cholecystokinin
(CCK) on the actin cytoskeleton by genetic manipulation of Chinese
hamster ovary (CHO) cells stably transfected with the CCK-A receptor. In these cells, as in rat acini, CCK activated p38 mitogen-activated protein (MAP) kinase and increased the phosphorylation of HSP27. This
effect could be blocked with the p38 MAP kinase inhibitor SB-203580.
Examination by confocal microscopy of cells stained with rhodamine
phalloidin showed that CCK dose-dependently induced changes of the
actin cytoskeleton, including cell shape changes, which were coincident
with actin cytoskeleton fragmentation and formation of actin filament
patches in the cells. To further evaluate the role of HSP27, CHO-CCK-A
cells were transfected with expression vectors for either wild-type
(wt) or mutant (3A, 3G, and 3D) human HSP27. Overexpression of wt-HSP27
and 3D-HSP27 inhibited the effects on the actin cytoskeleton seen after
high-dose CCK stimulation. In contrast, overexpression of
nonphosphorylatable mutants, 3A- and 3G-HSP27, or inhibition of
phosphorylation of HSP27 by preincubation of wt-HSP27 transfected cells
with SB-203580 did not protect the actin cytoskeleton. These results
suggest that phosphorylation of HSP27 is required to stabilize the
actin cytoskeleton and to protect the cells from the effects of high
concentrations of CCK.
heat shock protein; cholecystokinin; p38 mitogen-activated protein
kinase; microfilaments |
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| ISSN: | 0363-6143 1522-1563 |
| DOI: | 10.1152/ajpcell.1999.277.6.c1032 |