[The phosphorylation and tyrosine kinase activity of an internalized complex of epidermal growth factor and its receptor].
A study was made of the functional state of the epidermal growth factor (EGF)--receptor complexes in A-431 cells. Conditions of surface bound EGF extraction were selected which allow to consider the intracellular EGF--receptor complexes only. A procedure of high efficient and specific immunoprecipitation of tyrosyl-phosphorylated EGF receptors was developed. It is shown that the dissociation of EGF--receptor complexes leads to receptor dephosphorylation due to a rapid and reversible inactivation of EGF receptor tyrosine kinase. The internalized receptor is found to be tyrosyl-phosphorylated and to retain tyrosine kinase for at least an hour after the internalization. The dynamics of dissociation, degradation and dephosphorylation of EGF--receptor complexes has been estimated. The rates of these processes prove to be almost negligible for the first 2.5 hours after internalization.
Reshetnikova
G F
GF
Nesterov
A M
AM
Nikol'skiĭ
N N
NN
D000255:Adenosine Triphosphate / Q000378:metabolism; D000911:Antibodies, Monoclonal; D002460:Cell Line; D002846:Chromatography, Affinity; D004586:Electrophoresis; D004815:Epidermal Growth Factor / Q000032:analysis / Q000378:metabolism*; D066246:ErbB Receptors / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007457:Iodine Radioisotopes; D010761:Phosphorus Radioisotopes; D010766:Phosphorylation; D011233:Precipitin Tests; D011505:Protein-Tyrosine Kinases / Q000032:analysis / Q000378:metabolism*; D013997:Time Factors; D014407:Tumor Cells, Cultured / Q000201:enzymology
D000911:Antibodies, Monoclonal; D007457:Iodine Radioisotopes; D010761:Phosphorus Radioisotopes; D004815:Epidermal Growth Factor; D000255:Adenosine Triphosphate; D066246:ErbB Receptors; D011505:Protein-Tyrosine Kinases
Fosforilirovanie i tirozinkinaznaia aktivnost' internalizovannogo kompleksa épidermal'nogo faktora rosta i ego retseptora.