Jeffrey Segall's Lab

Kempiak et al. 2003 Journal of Cell Biology

Journal of Cell Biology 2003 Sep 1;162(5):781-7

Local signaling by the EGF receptor.

Kempiak SJ, Yip SC, Backer JM, Segall JE.

Department of Anatomy and Structural Biology, Albert Einstein College of Medicine 

Abstract

Differing spatial scales of signaling cascades are critical for cell orientation during chemotactic responses. We used biotin EGF bound to streptavidin-coupled magnetic beads to locally stimulate cells overexpressing the EGF receptor. We have found that EGF-induced actin polymerization remains localized even under conditions of receptor overexpression. Conversely, EGF-induced ERK activation spreads throughout the cell body after EGF bead stimulation. The localized actin polymerization is independent of PI3-kinase and rho protein activity and requires Arp2/3 complex and cofilin function. Thus, we find differing spatial scales of signaling from the EGF receptor, supporting models of chemotaxis that integrate short- and long-range signaling. 

 

Figure 1A movie. Phase-contrast movie of MTLn3:EGFR cells exposed to EGF beads at frame 12, one frame per 15 seconds. Beads are added when the image jerks, and
then are visible as dark spots. Note that some beads induce localized increases in phase density (actin polymerization) while others induce a protrusion with the bead at the tip. 

Figure 1B movie. Three-dimensional projection series from a confocal z-series of a cell showing localized actin polymerization (red) around an EGF bead (green). In this case there was limited rotrusion induced by the bead.

 

Figure 1C movie. Three-dimensional projection series from a confocal z-series of a cell showing an actin protrusion induced by an EGF bead (green). In this case the bead induced extensive protrusion.