Activation of phosphatidylinositol 3-kinase by prolactin in Nb2 cells.
In the present studies, using anti-phosphotyrosine (PY20) and PI3-kinase (p85) antibodies, we have shown that PRL causes activation of phosphatidyl inositol 3-kinase (PI3-kinase) in vitro in a dose- and time-dependent manner in Nb2 cells. PRL activated PI3-kinase was completely inhibited by LY294002 (1 microgram/ml). Stimulation of the cells with PRL also increased tyrosine phosphorylation of the 85-kDa regulatory subunit. Moreover, in vitro kinase assay followed by SDS-PAGE protein separation demonstrated the phosphorylation of several other proteins besides the p85. However, no direct association between p85 and JAK2 tyrosine kinase was observed. These results indicate, for the first time, the involvement of PI3-kinase in PRL-stimulated Nb2 cell growth.
al-Sakkaf
K A
KA
Department of Human Metabolism and Clinical Biochemistry, University of Sheffield Medical School, United Kingdom.
Dobson
P R
PR
Brown
B L
BL
D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002867:Chromones / Q000494:pharmacology; D004789:Enzyme Activation; D009025:Morpholines / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011233:Precipitin Tests; D011388:Prolactin / Q000494:pharmacology*
D002867:Chromones; D009025:Morpholines; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D011388:Prolactin; D019869:Phosphatidylinositol 3-Kinases; D017853:Phosphotransferases (Alcohol Group Acceptor)