Signalling pathways regulating the dephosphorylation of Ser729 in the hydrophobic domain of protein kinase Cepsilon upon cell passage.
J Biol Chem
; 276(13): 10437-42, 2001 Mar 30.
Article
in En
| MEDLINE
| ID: mdl-11121415
ABSTRACT
We have recently demonstrated that in quiescent fibroblasts protein kinase C (PKC) epsilon(95) is phosphorylated at Ser(729), Ser(703), and Thr(566) and that upon passage of quiescent cells phosphorylation at Ser(729) is lost, giving rise to PKCepsilon(87). Ser(729) may be rephosphorylated later, suggesting cycling between PKCepsilon(87) and PKCepsilon(95). Here we show that the dephosphorylation at Ser(729) is insensitive to okadaic acid, calyculin, ascomycin C, and cyclosporin A, suggesting that dephosphorylation at this site is not mediated through protein phosphatases 1, 2A or 2B. We demonstrate that this dephosphorylation at Ser(729) requires serum and cell readhesion and is sensitive to rapamycin, PD98059, chelerythrine, and Ro-31-8220. These results suggest that the phosphorylation status of Ser(729) in the hydrophobic domain at Ser(729) is regulated independently of the phosphorylation status of other sites in PKCepsilon, by a mTOR-sensitive phosphatase. The mitogen-activated protein kinase pathway and PKC are also implicated in regulating the dephosphorylation at Ser(729).
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Protein Kinase C
/
Signal Transduction
/
Tacrolimus
/
Isoenzymes
Language:
En
Journal:
J Biol Chem
Year:
2001
Document type:
Article
Affiliation country:
Reino Unido