Đang chuẩn bị nút TẢI XUỐNG, xin hãy chờ
Tải xuống
We used two inhibitors of the signaling enzyme phosphatidylinositol 3-kin-ase (PtdIns3K), wortmannin and LY294002, to evaluate the potential involvement of PtdIns3K in the activation of the MAP kinases (MAPK), Erk1 and Erk2. In dose–response studies carried out on six different cell lines and a primary cell culture, we analyzed the ability of the inhibitors to block phosphorylation of protein kinase B⁄akt (PKB⁄akt) at Ser473 as a measure of PtdIns3K activity, or the phosphorylation of Erk1⁄2 at activa-ting Thr⁄Tyr sites as a measure of the extent of activation of MAPK⁄Erk kinase (MEK⁄Erk). . | iFEBS Journal Acute activation of Erk1 Erk2 and protein kinase B akt proceed by independent pathways in multiple cell types Doris Chiu Kewei Ma Alexander Scott and Vincent Duronio Department of Medicine University of British Columbia and Vancouver CoastalHealth Research Institute Jack BellResearch Centre Vancouver Canada Keywords cross-talk cytokine inhibitors kinase phosphorylation Correspondence V. Duronio Jack BellResearch Centre Rm. 255 2660 Oak St Vancouver British Columbia V6H 3Z6 Canada Fax 1 604 875 4497 Tel 1 604 875 4707 E-mail vduronio@interchange.ubc.ca Received 17 June 2005 accepted 7 July 2005 doi 10.1111 j.1742-4658.2005.04850.x We used two inhibitors of the signaling enzyme phosphatidylinositol 3-kin-ase PtdIns3K wortmannin and LY294002 to evaluate the potential involvement of PtdIns3K in the activation of the MAP kinases MAPK Erk1 and Erk2. In dose-response studies carried out on six different cell lines and a primary cell culture we analyzed the ability of the inhibitors to block phosphorylation of protein kinase B akt PKB akt at Ser473 as a measure of PtdIns3K activity or the phosphorylation of Erk1 2 at activating Thr Tyr sites as a measure of the extent of activation of MAP Erk kinase MEK Erk . In three different hemopoietic cell lines stimulated with cytokines and in HEK293 cells stimulated with serum either wortmannin or LY294002 but never both could partially block phosphorylation of Erks. The same observations were made in a B-cell line and in primary fibroblasts. In only one cell type the A20 B cells was there a closer correlation between the PtdIns3K inhibition by both inhibitors and their corresponding effects on Erk phosphorylation. However this stands out as an exception that gives clues to the mechanism by which cross-talk might occur. In all other cells acute activation of the pathway leading to Erk phosphorylation could proceed independently of PtdIns3K activation. In a biological assay comparing these two pathways the ability of .
