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Phosphatidylinositol 3‐kinase/Akt plays a role in sphingosine 1‐phosphate‐stimulated HSP27 induction in osteoblasts
Author(s) -
Takai Shinji,
Tokuda Haruhiko,
MatsushimaNishiwaki Rie,
Hanai Yoshiteru,
Kato Kanefusa,
Kozawa Osamu
Publication year - 2006
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.20846
Subject(s) - protein kinase b , sphingosine , phosphorylation , wortmannin , phosphatidylinositol , microbiology and biotechnology , ly294002 , pi3k/akt/mtor pathway , kinase , sphingosine kinase 1 , chemistry , hsp27 , biology , biochemistry , sphingosine 1 phosphate , signal transduction , heat shock protein , hsp70 , receptor , gene
We previously reported that p38 mitogen‐activated protein (MAP) kinase plays a part in sphingosine 1‐phosphate‐stimulated heat shock protein 27 (HSP27) induction in osteoblast‐like MC3T3‐E1 cells. In the present study, we investigated whether phosphatidylinositol 3‐kinase (PI3K)/protein kinase B (Akt) is involved in the induction of HSP27 in these cells. Sphingosine 1‐phosphate time dependently induced the phosphorylation of Akt. Akt inhibitor, 1L‐6‐hydroxymethyl‐ chiro ‐inositol 2‐( R )‐2‐ O ‐methyl‐3‐ O ‐octadecylcarbonate, reduced the HSP27 induction stimulated by sphingosine 1‐phosphate. The sphingosine 1‐phosphate‐induced phosphorylation of GSK‐3β was suppressed by Akt inhibitor. The sphingosine 1‐phosphate‐induced HSP27 levels were attenuated by LY294002 or wortmannin, PI3K inhibitors. Furthermore, LY294002 or Akt inhibitor did not affect the sphingosine 1‐phosphate‐induced phosphorylation of p38 MAP kinase and SB203580, a p38 MAP kinase inhibitor, had little effect on the phosphorylation of Akt. These results suggest that PI3K/Akt plays a part in the sphingosine 1‐phosphate‐stimulated induction of HSP27, maybe independently of p38 MAP kinase, in osteoblasts. J. Cell. Biochem. 98: 1249–1256, 2006. © 2006 Wiley‐Liss, Inc.