Differential Translocation of Protein Kinase C ϵ during HeLa Cell Adhesion to a Gelatin Substratum

doi:10.1074/jbc.271.22.13008

Differential Translocation of Protein Kinase C ϵ during HeLa Cell Adhesion to a Gelatin Substratum*

From the ^‡ Department of Biology, Kyungpook National University, Taegu 702-701, Korea, the
Laboratory of Medical Genetics, Institute for Medical Science, Ajou University, Suwon 441-749, Korea, and the
^¶ Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003

^∥ To whom correspondence should be addressed:
Dept. of Biochemistry and Molecular Biology, University of Massachusetts, GRC Tower B, Amherst, MA 01003.
Tel.: 413-545-2048; Fax: 413-545-3291.

Abstract

The spreading of HeLa cells, following attachment to a collagen or gelatin substratum, requires the activation of protein kinase C (PKC). Membrane-bound PKC was previously shown to be activated during cell attachment and in response to the activation of a series of lipid second messengers turned on by the ligation of β1-integrin collagen receptors. HeLa cells express the α, γ, ϵ, ζ, λ, and ι isozymes of PKC as determined by Western blotting with specific antibodies. Only PKCϵ redistributed from the cytosol to the membrane during cell adhesion. Most of the PKCϵ in cells that were in suspension was in the cytosolic fraction. During cell attachment to a gelatin matrix, all of the PKCϵ moved out of the cytosol, with most going to the membrane fraction. After the cells became fully spread, PKCϵ began to reappear in the cytosol. Translocation of PKCϵ was not observed during the adhesion of cells to culture dishes where cells nonspecifically attach but do not spread. The conventional PKCα and -γ isozymes were translocated from the cytosol to the membrane only when phorbol ester was present at a concentration that increases the rate and extent of cell spreading. Under normal conditions, i.e. in the absence of phorbol ester, PKCϵ appears to be the PKC isozyme responsible for the regulation of HeLa cell adhesion to the extracellular matrix.

Footnotes

↵* This work was supported by Grant GM-29127 from the National Institutes of General Medical Sciences (to B. S. J.) and by grants from Korea Science and Engineering Foundation and the Ministry of Education (to J. S. C.). The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵¹ The abbreviations used are:

ECM

extracellular matrix

PKC

protein kinase C

PMA

phorbol 12-myristate 13-acetate.
↵² J-S. Chun, M-J. Ha, and B. S. Jacobson, manuscript in preparation.
- Received March 12, 1996.