Prolactin receptor triggering. Evidence for rapid tyrosine kinase activation. J Biol Chem 1992 Nov 25;267(33):24076-81
Date
11/25/1992Pubmed ID
1385436Scopus ID
2-s2.0-0027057982 (requires institutional sign-in at Scopus site) 120 CitationsAbstract
The mechanism of action of prolactin (PRL) has remained obscure despite the unveiling of the primary structure of PRL receptors. The present study demonstrates rapid PRL receptor-mediated tyrosine phosphorylation of at least three cellular proteins, designated p120, p97, and p40, in a rat T-lymphoma (Nb2-11C) as revealed by antiphosphotyrosine immunoblotting. One of the phosphotyrosyl proteins, p120, co-purified with activated PRL receptor complexes obtained using either anti-ligand or anti-receptor antibodies. Furthermore, in vitro incubation of affinity-purified PRL receptor complexes from PRL-stimulated cells with ATP in the presence of a tyrosine phosphatase inhibitor, resulted in a 10-15-fold increase in the phosphotyrosine content of p120, as revealed by antiphosphotyrosine immunoblotting. Parallel experiments utilizing [gamma-32P]ATP confirmed a rapid and time-dependent incorporation of phosphate into p120 in the same affinity-purified PRL receptor complexes. These data provide strong evidence for the involvement of a tyrosine kinase in PRL signal transduction and suggest the presence of a tyrosine kinase within the activated PRL receptor complex.
Author List
Rui H, Djeu JY, Evans GA, Kelly PA, Farrar WLMESH terms used to index this publication - Major topics in bold
Adenosine TriphosphateAnimals
Autoradiography
Cell Line
Electrophoresis, Polyacrylamide Gel
Enzyme Activation
Humans
Immunoblotting
Kinetics
Membrane Proteins
Molecular Weight
Phosphoproteins
Phosphorus Radioisotopes
Phosphotyrosine
Prolactin
Protein-Tyrosine Kinases
Receptors, Prolactin
Tyrosine
