1. Differential Tyrosyl-Phosphorylation of Multiple Mitogen-activated Protein Kinase Isoforms in Response to Prolactin in Nb2 Lymphoma Cells
- Author
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Ignacio G. Camarillo, Bruce E. Linebaugh, and James A. Rillema
- Subjects
Gene isoform ,Cell type ,Time Factors ,Lymphoma ,Receptors, Prolactin ,Biology ,environment and public health ,General Biochemistry, Genetics and Molecular Biology ,Enzyme activator ,Tumor Cells, Cultured ,Animals ,Phosphorylation ,Extracellular Signal-Regulated MAP Kinases ,Phosphotyrosine ,Mitogen-Activated Protein Kinase 6 ,Mitogen-Activated Protein Kinase 1 ,Mitogen-Activated Protein Kinase 3 ,Kinase ,Protein-Tyrosine Kinases ,Molecular biology ,Prolactin ,Rats ,Isoenzymes ,enzymes and coenzymes (carbohydrates) ,Cell culture ,Mitogen-activated protein kinase ,Calcium-Calmodulin-Dependent Protein Kinases ,biology.protein ,Mitogen-Activated Protein Kinases ,hormones, hormone substitutes, and hormone antagonists ,Signal Transduction - Abstract
Prolactin (PRL) stimulates mitogenesis and differentiative processes in a variety of cell types. Not all of the molecules involved in PRL signaling, which follows an initial PRL-receptor interaction, have been identified. In the present studies, PRL is shown to stimulate the differential tyrosyl phosphorylation of three isoforms (ERK-1, 2, and 4) of mitogen-activated protein kinases (MAP kinase) in a rat pre-T lymphoma cell line (Nb2). Evidence also suggests that PRL stimulates the tyrosyl phosphorylation of ERK-3, a MAP kinase isoform recently identified. When G1-arrested Nb2 cells are treated with 50 ng/ml oPRL, ERK-1 through 3 become tyrosyl phosphorylated within minutes (an indication of enzyme activation) and then become dephosphorylated within 30 min. Conversely, ERK-4 is rapidly tyrosyl phosphorylated by 5 min, and remains in this state for at least 1 hr.
- Published
- 1997
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