Prolactin-induced phosphorylation and nuclear translocation of MAP kinase in Nb2 lymphoma cells.
The coupling of prolactin (PRL) receptor ligation to activation of mitogen-activated protein (MAP) kinase was sought in rat Nb2 lymphoma cells, a pre-T lymphocyte line dependent upon lactogens for proliferation. Addition of PRL (20 ng/ml) to Nb2 cells, growth arrested in the early G1 phase of cell cycle, stimulated rapid tyrosyl phosphorylation of MAP kinase (min). Phosphorylated MAP kinase subsequently translocated to the nucleus, with kinetics essentially identical to those demonstrated for nuclear accumulation of PRL. The rapidity of MAP kinase activation suggests an intermediary role for this enzyme in PRL receptor signalling. Moreover, nuclear translocation of MAP kinase provides an interactive mechanism by which PRL, together with its nuclear receptor, may regulate transcription requisite for mitogenesis.
Department of Pharmacology and Toxicology, University of North Dakota School of Medicine, Grand Forks 58202-9037.
A R
AR
Buckley
Y P
YP
Rao
D J
DJ
Buckley
P W
PW
Gout
D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000302:isolation & purification / Q000378:metabolism*; D002460:Cell Line; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism*; D004789:Enzyme Activation; D007700:Kinetics; D008223:Lymphoma; D010766:Phosphorylation; D011388:Prolactin / Q000378:metabolism / Q000494:pharmacology*; D011499:Protein Processing, Post-Translational / Q000187:drug effects*; D051381:Rats; D011981:Receptors, Prolactin / Q000378:metabolism; D013997:Time Factors; D014407:Tumor Cells, Cultured
D011981:Receptors, Prolactin; D011388:Prolactin; D017871:Calcium-Calmodulin-Dependent Protein Kinases