Journal
CELLULAR SIGNALLING
Volume 20, Issue 7, Pages 1359-1367Publisher
ELSEVIER SCIENCE INC
DOI: 10.1016/j.cellsig.2008.03.007
Keywords
c-src; EGF receptor; endocytosis; macropinocytosis; tyrosine kinase
Categories
Funding
- NIGMS NIH HHS [R01 GM057966, GM57966, R01 GM057966-08] Funding Source: Medline
Ask authors/readers for more resources
c-Src is a non-receptor tyrosine kinase that associates with both the plasma membrane and endosomal compartments. In many human cancers, especially breast cancer, c-Src and the EGF receptor (EGFR) are overexpressed. Dual overexpression of c-Src and EGFR correlates with a Src-dependent increase in activation of EGFR, and synergism between these two tyrosine kinases increases the mitogenic activity of EGFR. Despite extensive studies of the functional interaction between c-Src and EGFR, little is known about the interactions in the trafficking pathways for the two proteins and how that influences signaling. Given the synergism between c-Src and EGFR, and the finding that EGFR is internalized and can signal from endosomes, we hypothesized that c-Src and EGFR traffic together through the endocytic pathway. Here we use a regulatable c-SrcGFP fusion protein that is a bona fide market for c-Src to show that c-Src undergoes constitutive macropinocytosis from the plasma membrane into endocytic compartments. The movement of c-Src was dependent on its tyrosine kinase activity. Stimulation of cells with EGF revealed that c-Src traffics into the cell with activated EGFR and that c-Src expression and kinase activity prolongs EGFR activation. Surprisingly, even in the absence of EGF addition, c-Src expression induced activation of EGFR and of EGFR-mediated downstream signaling targets ERK and Shc. These data suggest that the synergy between c-Src and EGFR also occurs as these two kinases traffic together, and that their co-localization promotes EGFR-mediated signaling. (c) 2008 Elsevier Inc. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available