[The role of Src-kinase in the regulation of endocytosis of EGF-receptor complexes. Distribution of clathrin after stimulation of EGR endocytosis in various cell lines during inhibition of Src-kinase activity].
A distribution of EGF receptor and clathrin during EGF endocytosis in A431, HER14, WT and PURO cell lines was studied by indirect immunofluorescence. Though the initial distribution of EGF-receptors on A431 and HER14 cells was somewhat different, the late stages of endocytosis proceeded equally and were marked by formation of bright spots in the juxtanuclear region characteristic of the late endosomes. The Src-family kinase inhibitor CGP77675 had no influence on the dynamics of receptor endocytosis at the immunofluorescent level in both cell lines. Stimulation of EGF-receptor endocytosis in A431 cells did not also result in any redistribution of clathrin in the areas where the majority of EGF-receptors are localized, i.e. in the lateral plasma membrane both in the control cells and under CGP77675 treatment. Clathrin in A431, WT and PURO cells demonstrated even a punctuated pattern throughout the cytoplasm with some accumulation in the juxtanuclear region. This distribution depended neither on the absence or presence of Src activity nor on EGF addition. The data obtained indicate that 1) EGF-receptors do not serve as the initiation sites during clathrin coated pit assembly; 2) Src-kinase activation does not result in significant clathrin redistribution in the plasma membrane, and its influence on EGF endocytosis can be considered as a secondary effect.
Melikova
M S
MS
Institute of Cytology RAS, St. Petersburg.
Zheleznova
N N
NN
Nikol'skiĭ
N N
NN
Kornilova
E S
ES
D000818:Animals; D002460:Cell Line; D002966:Clathrin / Q000378:metabolism*; D004705:Endocytosis / Q000187:drug effects*; D004815:Epidermal Growth Factor / Q000378:metabolism*; D066246:ErbB Receptors / Q000378:metabolism*; D019085:Fluorescent Antibody Technique, Direct; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D011743:Pyrimidines / Q000494:pharmacology; D011758:Pyrroles / Q000494:pharmacology; D019061:src-Family Kinases / Q000037:antagonists & inhibitors* / Q000235:genetics
D002966:Clathrin; D011743:Pyrimidines; D011758:Pyrroles; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D019061:src-Family Kinases; C119957:CGP 77675