TY - JOUR
T1 - Actin polymerization localizes to the activated epidermal growth factor receptor in the plasma membrane, independent of the cytosolic free calcium transient
AU - Rijken, P. J.
AU - Post, S. M.
AU - Hage, W. J.
AU - Van Bergen En Henegouwen, P. M.P.
AU - Verkleij, A. J.
AU - Boonstra, J.
PY - 1995/5
Y1 - 1995/5
N2 - Epidermal growth factor (EGF) induces rapid actin filament assembly in the membrane skeleton of A431 cells, leading to a ∼30% rise in cellular filamentous actin levels. EGF-induced actin polymerization depends upon EGF receptor (EGFR) tyrosine kinase activity, since the selective tyrosine kinase inhibitor AG213 abolishes EGF-induced actin polymerization. In accordance, confocal laser scanning microscopy shows that newly assembled actin filaments localize selectively to the tyrosine-phosphorylated EGFR in the plasma membrane, since actin polymerization is not observed at the internalized tyrosine-phosphorylated EGFR. Actin binding proteins (ABP's) are generally believed to regulate actin filament assembly. Ca2+ is known as one of the important regulatory factors for the activity of ABP's in vitro [15]. Therefore, we investigated the importance of the EGF-induced transient rise in [Ca2+](i) for the regulation of actin polymerization in vivo. Continuous high [Ca2+](i) in the millimolar range induces a prominent rise in cellular filamentous actin levels to ~50% over control cells. However, actin polymerization is unimpaired under conditions which effectively block the EGF-induced [Ca2+](i) transient. These data demonstrate that EGF-induced actin polymerization localizes to the activated EGFR in the membrane skeleton, independent of the cytosolic free calcium transient.
AB - Epidermal growth factor (EGF) induces rapid actin filament assembly in the membrane skeleton of A431 cells, leading to a ∼30% rise in cellular filamentous actin levels. EGF-induced actin polymerization depends upon EGF receptor (EGFR) tyrosine kinase activity, since the selective tyrosine kinase inhibitor AG213 abolishes EGF-induced actin polymerization. In accordance, confocal laser scanning microscopy shows that newly assembled actin filaments localize selectively to the tyrosine-phosphorylated EGFR in the plasma membrane, since actin polymerization is not observed at the internalized tyrosine-phosphorylated EGFR. Actin binding proteins (ABP's) are generally believed to regulate actin filament assembly. Ca2+ is known as one of the important regulatory factors for the activity of ABP's in vitro [15]. Therefore, we investigated the importance of the EGF-induced transient rise in [Ca2+](i) for the regulation of actin polymerization in vivo. Continuous high [Ca2+](i) in the millimolar range induces a prominent rise in cellular filamentous actin levels to ~50% over control cells. However, actin polymerization is unimpaired under conditions which effectively block the EGF-induced [Ca2+](i) transient. These data demonstrate that EGF-induced actin polymerization localizes to the activated EGFR in the membrane skeleton, independent of the cytosolic free calcium transient.
UR - http://www.scopus.com/inward/record.url?scp=0029054135&partnerID=8YFLogxK
U2 - 10.1006/excr.1995.1150
DO - 10.1006/excr.1995.1150
M3 - Article
AN - SCOPUS:0029054135
SN - 0014-4827
VL - 218
SP - 223
EP - 232
JO - Experimental Cell Research
JF - Experimental Cell Research
IS - 1
ER -