Many proteins are anchored to the cell membrane by glycosylphosphatidylinositol (GPI). One of the functions proposed for the GPI anchor is as a possible mediator in signal transduction through its hydrolysis. GPI-specific phospholipase D (GPI-PLD) is a secretory protein that is suggested to be involved in the release of GPI-anchored protein from the membrane. In the present study we examined how GPI-PLD is involved in signal transduction. When introduced exogenously and overexpressed in cells, GPI-PLD cleaved the GPI anchors in the early secretory pathway, possibly in the endoplasmic reticulum, resulting in an increased production of diacylglycerol. Experiments in vitro and in vivo showed that the association of protein kinase Cα (PKCα) with membranes was increased markedly by expression of GPI-PLD in cells. Furthermore, sucrose-density-gradient centrifugation and immunofluorescence microscopy demonstrated that PKCα was translocated to the endoplasmic reticulum membrane in cells expressing GPI-PLD, in contrast with its association with the plasma membrane in cells treated with PMA. We also confirmed that the phosphorylation of c-Fos as well as PKCα itself was greatly enhanced by the expression of GPI-PLD. Taken together, these results suggest that GPI-PLD is involved in intracellular cleavage of the GPI anchor, which is a new potential source of diacylglycerol production to activate PKCα.
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September 1999
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Research Article|
August 24 1999
Intracellular cleavage of glycosylphosphatidylinositol by phospholipase D induces activation of protein kinase Cα
Hiroshi TSUJIOKA;
Hiroshi TSUJIOKA
*Department of Biochemistry, Fukuoka University, School of Medicine, Jonan-ku, Fukuoka 814-0180, Japan
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Noboru TAKAMI;
Noboru TAKAMI
†Radioisotope Laboratory, Fukuoka University, School of Medicine, Jonan-ku, Fukuoka 814-0180, Japan
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Yoshio MISUMI;
Yoshio MISUMI
*Department of Biochemistry, Fukuoka University, School of Medicine, Jonan-ku, Fukuoka 814-0180, Japan
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Yukio IKEHARA
Yukio IKEHARA
1
*Department of Biochemistry, Fukuoka University, School of Medicine, Jonan-ku, Fukuoka 814-0180, Japan
1To whom correspondence should be addressed (mm031321@msat.fukuoka-u.ac.jp).
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Publisher: Portland Press Ltd
Received:
December 09 1998
Revision Received:
June 01 1999
Accepted:
June 25 1999
Online ISSN: 1470-8728
Print ISSN: 0264-6021
The Biochemical Society, London © 1999
1999
Biochem J (1999) 342 (2): 449–455.
Article history
Received:
December 09 1998
Revision Received:
June 01 1999
Accepted:
June 25 1999
Citation
Hiroshi TSUJIOKA, Noboru TAKAMI, Yoshio MISUMI, Yukio IKEHARA; Intracellular cleavage of glycosylphosphatidylinositol by phospholipase D induces activation of protein kinase Cα. Biochem J 1 September 1999; 342 (2): 449–455. doi: https://doi.org/10.1042/bj3420449
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